From b9d1ccd40a29a833e5b6589124aa408b2d62386d Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Sun, 10 Apr 2022 11:26:59 +0200
Subject: [PATCH 01/22] Progress towards ARM64 support

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/aeos/config/configure.ml  | 2 --
 src/owl/config/configure.ml   | 6 ------
 src/owl/core/owl_core_utils.c | 9 ++++++++-
 src/owl/core/owl_macros.h     | 4 +++-
 4 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index 95931ea96..e253a87de 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -34,8 +34,6 @@ let get_default_cflags =
   | Not_found ->
     [ "-g"
     ; "-O3"
-    ; "-Ofast"
-    ; "-march=native"
     ; "-funroll-loops"
     ; "-ffast-math"
     ; "-DSFMT_MEXP=19937"
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 77e4af0bc..2650ecb96 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -87,17 +87,11 @@ let default_cflags =
     [ (* Basic optimisation *)
       "-g"
     ; "-O3"
-    ; "-Ofast"
-    ; (* FIXME: experimental switches *)
-      (* "-mavx2"; "-mfma"; "-ffp-contract=fast"; *)
       (* Experimental switches, -ffast-math may break IEEE754 semantics*)
-      "-march=native"
-    ; "-mfpmath=sse"
     ; "-funroll-loops"
     ; "-ffast-math"
     ; (* Configure Mersenne Twister RNG *)
       "-DSFMT_MEXP=19937"
-    ; "-msse2"
     ; "-fno-strict-aliasing"
     ]
 
diff --git a/src/owl/core/owl_core_utils.c b/src/owl/core/owl_core_utils.c
index 1a5a09e9f..ea36bf306 100644
--- a/src/owl/core/owl_core_utils.c
+++ b/src/owl/core/owl_core_utils.c
@@ -207,7 +207,13 @@ void c_slicing_offset (struct caml_ba_array *X, int64_t *slice, int64_t *offset)
  * Code heavily inspired by Eigen (http://eigen.tuxfamily.org/).
  */
 
-
+#if defined(__arm__) || defined(__aarch64__)
+void query_cache_sizes(int* l1p, int* l2p, int* l3p) {
+  *l1p = 16 * 1024;
+  *l2p = 512 * 1024;
+  *l3p = 512 * 1024;
+}
+#elif
 OWL_INLINE void query_cache_sizes_intel(int* l1p, int* l2p, int* l3p) {
   int cpuinfo[4];
   int l1 = 0, l2 = 0, l3 = 0;
@@ -295,3 +301,4 @@ void query_cache_sizes(int* l1p, int* l2p, int* l3p) {
     *l3p = 512 * 1024;
   }
 }
+#endif
diff --git a/src/owl/core/owl_macros.h b/src/owl/core/owl_macros.h
index 7a17e56db..195dcf62b 100644
--- a/src/owl/core/owl_macros.h
+++ b/src/owl/core/owl_macros.h
@@ -86,6 +86,8 @@ typedef struct { double r, i; } complex_double;
   #define OWL_ARCH_x86_64 0
 #endif
 
+#if defined(__arm__) || defined(__aarch64__)
+#elif
 #if defined(__PIC__) && OWL_ARCH_i386
   #define CPUID(cpuinfo,func,id) \
     __asm__ __volatile__ ("xchgl %%ebx, %k1; cpuid; xchgl %%ebx,%k1": "=a" (cpuinfo[0]), "=&r" (cpuinfo[1]), "=c" (cpuinfo[2]), "=d" (cpuinfo[3]) : "a" (func), "c" (id));
@@ -96,7 +98,7 @@ typedef struct { double r, i; } complex_double;
   #define CPUID(cpuinfo,func,id) \
     __asm__ __volatile__ ("cpuid": "=a" (cpuinfo[0]), "=b" (cpuinfo[1]), "=c" (cpuinfo[2]), "=d" (cpuinfo[3]) : "0" (func), "2" (id) );
 #endif
-
+#endif
 
 //  Other
 

From 8044bb5601b78322488a89036b77fba4d9f62e90 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Mon, 11 Apr 2022 14:33:05 +0200
Subject: [PATCH 02/22] Re-introduce Ofast flag

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 INSTALL.md                   | 8 ++++----
 src/aeos/config/configure.ml | 1 +
 src/owl/config/configure.ml  | 1 +
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/INSTALL.md b/INSTALL.md
index 614ab1a57..68f5d5b38 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -15,18 +15,18 @@ before compilation:
 - `OWL_CFLAGS` allows to change the default flags passed to the C targets,
   it defaults to
   ```
-  OWL_CFLAGS="-g -O3 -Ofast -march=native -mfpmath=sse -funroll-loops -ffast-math -DSFMT_MEXP=19937 -msse2 -fno-strict-aliasing -Wno-tautological-constant-out-of-range-compare"`
+  OWL_CFLAGS="-g -O3 -Ofast -funroll-loops -ffast-math -DSFMT_MEXP=19937 -msse2 -fno-strict-aliasing"`
   ```
 
 - `OWL_AEOS_CFLAGS` allows to change the default flags passed to the C targets
   when compiling AEOS. It defaults to
   ```
-  OWL_AEOS_CFLAGS="-g -O3 -Ofast -march=native -funroll-loops -ffast-math -DSFMT_MEXP=19937 -fno-strict-aliasing"
+  OWL_AEOS_CFLAGS="-g -O3 -Ofast -funroll-loops -ffast-math -DSFMT_MEXP=19937 -fno-strict-aliasing"
   ```
 
 - `OWL_DISABLE_LAPACKE_LINKING_FLAG=1` disables the `-llapacke` flag in the
-  linking options. This is useful when you have lapacke installed on
-  non-standard location.
+  linking options. This may be useful when you have certain unusual lapacke
+  setups, do not use it unless you know what you are doing.
 
 If you are not using `opam`, you should run `make clean` before recompiling
 the library after having changed any of those environment variables.
diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index e253a87de..7d9f734a5 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -34,6 +34,7 @@ let get_default_cflags =
   | Not_found ->
     [ "-g"
     ; "-O3"
+    ; "-Ofast"
     ; "-funroll-loops"
     ; "-ffast-math"
     ; "-DSFMT_MEXP=19937"
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 2650ecb96..f6e3ac3f6 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -87,6 +87,7 @@ let default_cflags =
     [ (* Basic optimisation *)
       "-g"
     ; "-O3"
+    ; "-Ofast"
       (* Experimental switches, -ffast-math may break IEEE754 semantics*)
     ; "-funroll-loops"
     ; "-ffast-math"

From b5db63299b4dee7078008a48bef784c3a3ed4555 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Mon, 11 Apr 2022 10:05:51 +0200
Subject: [PATCH 03/22] unit_signal: fix test

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 test/unit_signal.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/unit_signal.ml b/test/unit_signal.ml
index 9eea83008..046b12f2d 100644
--- a/test/unit_signal.ml
+++ b/test/unit_signal.ml
@@ -75,7 +75,7 @@ module To_test = struct
     M.set freqz_ref [| 3 |] { Complex.re = -0.0536; im = 0.0464 };
     let f =
       freqz ~n:4 ~whole:false (freqz_num |> M.to_array) (freqz_den |> M.to_array)
-      |> fun (a, b) -> b
+      |> snd
     in
     let max_err =
       (Owl_dense_ndarray.Z.map2 (fun x a -> Complex.sub x a) f freqz_ref

From ac2e0d7221e73a3649d8663cfeaf9144bcd7f0dd Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Mon, 11 Apr 2022 17:14:29 +0200
Subject: [PATCH 04/22] Update architecture detection

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/aeos/config/configure.ml | 35 ++++++++++++++++++++++--------
 src/owl/config/configure.ml  | 42 ++++++++++++++++++++++++++----------
 2 files changed, 57 insertions(+), 20 deletions(-)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index 7d9f734a5..0294b0aed 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -24,7 +24,7 @@ let get_os_type c =
   | None   -> ""
 
 
-let get_default_cflags =
+let get_default_cflags c =
   try
     Sys.getenv "OWL_AEOS_CFLAGS"
     |> String.trim
@@ -32,14 +32,31 @@ let get_default_cflags =
     |> List.filter (fun s -> String.trim s <> "")
   with
   | Not_found ->
-    [ "-g"
-    ; "-O3"
-    ; "-Ofast"
-    ; "-funroll-loops"
-    ; "-ffast-math"
-    ; "-DSFMT_MEXP=19937"
-    ; "-fno-strict-aliasing"
-    ]
+    let arch =
+      let defines =
+        C.C_define.import
+          c
+          ~includes:[]
+          [ "__x86_64__", Switch
+          ; "__i386__", Switch
+          ; "__aarch64__", Switch
+          ; "__arm__", Switch
+          ]
+      in
+      let open C in
+      match List.map snd defines with
+      | Switch true :: _ -> `x86_64
+      | _ :: Switch true :: _ -> `x86
+      | _ :: _ :: Switch true :: _ -> `arm64
+      | _ :: _ :: _ :: Switch true :: _ -> `arm
+      | _ -> `unknown
+    in
+    [ "-g"; "-O3"; "-Ofast" ]
+    @ (match arch with
+      | `x86_64 -> [ "-march=native"; "-msse2" ]
+      | `arm64  -> [ "-mcpu=apple-m1" ]
+      | _       -> [])
+    @ [ "-funroll-loops"; "-ffast-math"; "-DSFMT_MEXP=19937"; "-fno-strict-aliasing" ]
 
 
 let get_openmp_cflags c =
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index f6e3ac3f6..a93d7b4d3 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -84,17 +84,37 @@ let default_cflags =
     |> List.filter (fun s -> String.trim s <> "")
   with
   | Not_found ->
-    [ (* Basic optimisation *)
-      "-g"
-    ; "-O3"
-    ; "-Ofast"
-      (* Experimental switches, -ffast-math may break IEEE754 semantics*)
-    ; "-funroll-loops"
-    ; "-ffast-math"
-    ; (* Configure Mersenne Twister RNG *)
-      "-DSFMT_MEXP=19937"
-    ; "-fno-strict-aliasing"
-    ]
+    let arch =
+      let defines =
+        C.C_define.import
+          c
+          ~includes:[]
+          [ "__x86_64__", Switch
+          ; "__i386__", Switch
+          ; "__aarch64__", Switch
+          ; "__arm__", Switch
+          ]
+      in
+      let open C in
+      match List.map snd defines with
+      | Switch true :: _ -> `x86_64
+      | _ :: Switch true :: _ -> `x86
+      | _ :: _ :: Switch true :: _ -> `arm64
+      | _ :: _ :: _ :: Switch true :: _ -> `arm
+      | _ -> `unknown
+    in
+    [ (* Basic optimisation *) "-g"; "-O3"; "-Ofast" ]
+    @ (match arch with
+      | `x86_64 -> [ "-march=native"; "-msse2" ]
+      | `arm64  -> [ "-mcpu=apple-m1" ]
+      | _       -> [])
+    @ [ (* Experimental switches, -ffast-math may break IEEE754 semantics*)
+        "-funroll-loops"
+      ; "-ffast-math"
+      ; (* Configure Mersenne Twister RNG *)
+        "-DSFMT_MEXP=19937"
+      ; "-fno-strict-aliasing"
+      ]
 
 
 let default_libs = [ "-lm" ]

From 7a3c434a926fea40f930aab906eb658f18d9c9ca Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Mon, 11 Apr 2022 17:14:40 +0200
Subject: [PATCH 05/22] ocamlformat

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 test/unit_signal.ml | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/test/unit_signal.ml b/test/unit_signal.ml
index 046b12f2d..bf5bec030 100644
--- a/test/unit_signal.ml
+++ b/test/unit_signal.ml
@@ -74,8 +74,7 @@ module To_test = struct
     M.set freqz_ref [| 2 |] { Complex.re = -0.5; im = -0.5 };
     M.set freqz_ref [| 3 |] { Complex.re = -0.0536; im = 0.0464 };
     let f =
-      freqz ~n:4 ~whole:false (freqz_num |> M.to_array) (freqz_den |> M.to_array)
-      |> snd
+      freqz ~n:4 ~whole:false (freqz_num |> M.to_array) (freqz_den |> M.to_array) |> snd
     in
     let max_err =
       (Owl_dense_ndarray.Z.map2 (fun x a -> Complex.sub x a) f freqz_ref

From efc51a15450eca2ef6a712f994cafab6d193d930 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Mon, 11 Apr 2022 17:17:59 +0200
Subject: [PATCH 06/22] fixup! Update architecture detection

---
 src/aeos/config/configure.ml | 2 +-
 src/owl/config/configure.ml  | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index 0294b0aed..160c3aa11 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -92,7 +92,7 @@ let () =
       (* configure link options *)
       let libs = [] @ get_default_libs () @ get_openmp_libs c in
       (* configure compile options *)
-      let cflags = [] @ get_default_cflags @ get_openmp_cflags c in
+      let cflags = [] @ get_default_cflags c @ get_openmp_cflags c in
       (* assemble default config *)
       let conf : C.Pkg_config.package_conf = { cflags; libs } in
       C.Flags.write_sexp "aeos_c_flags.sexp" conf.cflags;
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index a93d7b4d3..3a79a16c0 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -76,7 +76,7 @@ let get_ocaml_devmode_flags _c =
   if not enable_devmode then [] else [ "-w"; "-32-27-6-37-3" ]
 
 
-let default_cflags =
+let default_cflags c =
   try
     Sys.getenv "OWL_CFLAGS"
     |> String.trim
@@ -268,7 +268,7 @@ some details on how your openblas has been installed and the output of
         []
         @ openblas_conf.cflags
         @ cblas_conf.cflags
-        @ default_cflags
+        @ default_cflags c
         @ get_devmode_cflags c
         @ get_expmode_cflags c
         @ openmp_config.cflags

From 48a8b0e257c87be43f7f2c727f26a1087e19c5e1 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Tue, 12 Apr 2022 18:15:54 +0200
Subject: [PATCH 07/22] Improve architecture and os detection

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/aeos/config/configure.ml | 57 ++++++++++++++++++++++++++++++------
 src/owl/config/configure.ml  | 49 ++++++++++++++++++++++++++++---
 2 files changed, 93 insertions(+), 13 deletions(-)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index 160c3aa11..4b15c973e 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -5,6 +5,27 @@
 
 module C = Configurator.V1
 
+let detect_system_header =
+  {|
+  #if __APPLE__
+    #include <TargetConditionals.h>
+    #if TARGET_OS_IPHONE
+      #define PLATFORM_NAME "ios"
+    #else
+      #define PLATFORM_NAME "mac"
+    #endif
+  #elif __linux__
+    #if __ANDROID__
+      #define PLATFORM_NAME "android"
+    #else
+      #define PLATFORM_NAME "linux"
+    #endif
+  #elif WIN32
+    #define PLATFORM_NAME "windows"
+  #endif
+|}
+
+
 let bgetenv v =
   let v' =
     try Sys.getenv v |> int_of_string with
@@ -32,6 +53,25 @@ let get_default_cflags c =
     |> List.filter (fun s -> String.trim s <> "")
   with
   | Not_found ->
+    let os =
+      let header =
+        let file = Filename.temp_file "discover" "os.h" in
+        let fd = open_out file in
+        output_string fd detect_system_header;
+        close_out fd;
+        file
+      in
+      let platform =
+        C.C_define.import c ~includes:[ header ] [ "PLATFORM_NAME", String ]
+      in
+      match List.map snd platform with
+      | [ String "android" ] -> `android
+      | [ String "ios" ]     -> `ios
+      | [ String "linux" ]   -> `linux
+      | [ String "mac" ]     -> `mac
+      | [ String "windows" ] -> `windows
+      | _                    -> `unknown
+    in
     let arch =
       let defines =
         C.C_define.import
@@ -52,10 +92,11 @@ let get_default_cflags c =
       | _ -> `unknown
     in
     [ "-g"; "-O3"; "-Ofast" ]
-    @ (match arch with
-      | `x86_64 -> [ "-march=native"; "-msse2" ]
-      | `arm64  -> [ "-mcpu=apple-m1" ]
-      | _       -> [])
+    @ (match arch, os with
+      | `arm64, `mac -> [ "-mcpu=apple-m1" ]
+      | `arm64, _    -> [ "-march=native" ]
+      | `x86_64, _   -> [ "-march=native"; "-msse2" ]
+      | _            -> [])
     @ [ "-funroll-loops"; "-ffast-math"; "-DSFMT_MEXP=19937"; "-fno-strict-aliasing" ]
 
 
@@ -65,11 +106,9 @@ let get_openmp_cflags c =
   then []
   else (
     match get_os_type c with
-    | "linux"     -> [ "-fopenmp" ]
-    | "linux_elf" -> [ "-fopenmp" ]
-    | "macosx"    -> [ "-Xpreprocessor"; "-fopenmp" ]
-    | "mingw64"   -> [ "-fopenmp" ]
-    | _           -> [])
+    | "mingw64" | "linux" | "linux_elf" -> [ "-fopenmp" ]
+    | "macosx" -> [ "-Xpreprocessor"; "-fopenmp" ]
+    | _ -> [])
 
 
 let get_default_libs () = [ "-lm" ]
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 3a79a16c0..678dd668e 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -5,6 +5,27 @@
 
 module C = Configurator.V1
 
+let detect_system_header =
+  {|
+  #if __APPLE__
+    #include <TargetConditionals.h>
+    #if TARGET_OS_IPHONE
+      #define PLATFORM_NAME "ios"
+    #else
+      #define PLATFORM_NAME "mac"
+    #endif
+  #elif __linux__
+    #if __ANDROID__
+      #define PLATFORM_NAME "android"
+    #else
+      #define PLATFORM_NAME "linux"
+    #endif
+  #elif WIN32
+    #define PLATFORM_NAME "windows"
+  #endif
+|}
+
+
 let bgetenv v =
   let v' =
     try Sys.getenv v |> int_of_string with
@@ -84,6 +105,25 @@ let default_cflags c =
     |> List.filter (fun s -> String.trim s <> "")
   with
   | Not_found ->
+    let os =
+      let header =
+        let file = Filename.temp_file "discover" "os.h" in
+        let fd = open_out file in
+        output_string fd detect_system_header;
+        close_out fd;
+        file
+      in
+      let platform =
+        C.C_define.import c ~includes:[ header ] [ "PLATFORM_NAME", String ]
+      in
+      match List.map snd platform with
+      | [ String "android" ] -> `android
+      | [ String "ios" ]     -> `ios
+      | [ String "linux" ]   -> `linux
+      | [ String "mac" ]     -> `mac
+      | [ String "windows" ] -> `windows
+      | _                    -> `unknown
+    in
     let arch =
       let defines =
         C.C_define.import
@@ -104,10 +144,11 @@ let default_cflags c =
       | _ -> `unknown
     in
     [ (* Basic optimisation *) "-g"; "-O3"; "-Ofast" ]
-    @ (match arch with
-      | `x86_64 -> [ "-march=native"; "-msse2" ]
-      | `arm64  -> [ "-mcpu=apple-m1" ]
-      | _       -> [])
+    @ (match arch, os with
+      | `arm64, `mac -> [ "-mcpu=apple-m1" ]
+      | `arm64, _    -> [ "-march=native" ]
+      | `x86_64, _   -> [ "-march=native"; "-msse2" ]
+      | _            -> [])
     @ [ (* Experimental switches, -ffast-math may break IEEE754 semantics*)
         "-funroll-loops"
       ; "-ffast-math"

From ab17a401abf90560df4e5ee9fb840e4125f8e1ae Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Tue, 12 Apr 2022 18:19:03 +0200
Subject: [PATCH 08/22] config: cleanup unused open

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/aeos/config/configure.ml | 1 -
 src/owl/config/configure.ml  | 1 -
 2 files changed, 2 deletions(-)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index 4b15c973e..2d5bf398c 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -83,7 +83,6 @@ let get_default_cflags c =
           ; "__arm__", Switch
           ]
       in
-      let open C in
       match List.map snd defines with
       | Switch true :: _ -> `x86_64
       | _ :: Switch true :: _ -> `x86
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 678dd668e..775a39988 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -135,7 +135,6 @@ let default_cflags c =
           ; "__arm__", Switch
           ]
       in
-      let open C in
       match List.map snd defines with
       | Switch true :: _ -> `x86_64
       | _ :: Switch true :: _ -> `x86

From 7f4cc770f8dda14912d044fc1fee8e4439c3a9e4 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Tue, 12 Apr 2022 18:23:31 +0200
Subject: [PATCH 09/22] reintroduce -mfpmath=sse on x86_64

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/owl/config/configure.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 775a39988..5a672e8d0 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -146,7 +146,7 @@ let default_cflags c =
     @ (match arch, os with
       | `arm64, `mac -> [ "-mcpu=apple-m1" ]
       | `arm64, _    -> [ "-march=native" ]
-      | `x86_64, _   -> [ "-march=native"; "-msse2" ]
+      | `x86_64, _   -> [ "-march=native"; "-mfpmath=sse"; "-msse2" ]
       | _            -> [])
     @ [ (* Experimental switches, -ffast-math may break IEEE754 semantics*)
         "-funroll-loops"

From 69c7e386af7d22cb9e83033cac315e62c4c27d88 Mon Sep 17 00:00:00 2001
From: Marcello Seri <mseri@users.noreply.github.com>
Date: Thu, 14 Apr 2022 15:32:37 +0200
Subject: [PATCH 10/22] owl_macros.h: remove empty if

---
 src/owl/core/owl_macros.h | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/src/owl/core/owl_macros.h b/src/owl/core/owl_macros.h
index 195dcf62b..e3b6f2325 100644
--- a/src/owl/core/owl_macros.h
+++ b/src/owl/core/owl_macros.h
@@ -86,18 +86,17 @@ typedef struct { double r, i; } complex_double;
   #define OWL_ARCH_x86_64 0
 #endif
 
-#if defined(__arm__) || defined(__aarch64__)
-#elif
-#if defined(__PIC__) && OWL_ARCH_i386
-  #define CPUID(cpuinfo,func,id) \
-    __asm__ __volatile__ ("xchgl %%ebx, %k1; cpuid; xchgl %%ebx,%k1": "=a" (cpuinfo[0]), "=&r" (cpuinfo[1]), "=c" (cpuinfo[2]), "=d" (cpuinfo[3]) : "a" (func), "c" (id));
-#elif defined(__PIC__) && OWL_ARCH_x86_64
-  #define CPUID(cpuinfo,func,id) \
-    __asm__ __volatile__ ("xchg{q}\t{%%}rbx, %q1; cpuid; xchg{q}\t{%%}rbx, %q1": "=a" (cpuinfo[0]), "=&r" (cpuinfo[1]), "=c" (cpuinfo[2]), "=d" (cpuinfo[3]) : "0" (func), "2" (id));
-#else
-  #define CPUID(cpuinfo,func,id) \
-    __asm__ __volatile__ ("cpuid": "=a" (cpuinfo[0]), "=b" (cpuinfo[1]), "=c" (cpuinfo[2]), "=d" (cpuinfo[3]) : "0" (func), "2" (id) );
-#endif
+#if !defined(__arm__) && !defined(__aarch64__)
+  #if defined(__PIC__) && OWL_ARCH_i386
+    #define CPUID(cpuinfo,func,id) \
+      __asm__ __volatile__ ("xchgl %%ebx, %k1; cpuid; xchgl %%ebx,%k1": "=a" (cpuinfo[0]), "=&r" (cpuinfo[1]), "=c" (cpuinfo[2]), "=d" (cpuinfo[3]) : "a" (func), "c" (id));
+  #elif defined(__PIC__) && OWL_ARCH_x86_64
+    #define CPUID(cpuinfo,func,id) \
+      __asm__ __volatile__ ("xchg{q}\t{%%}rbx, %q1; cpuid; xchg{q}\t{%%}rbx, %q1": "=a" (cpuinfo[0]), "=&r" (cpuinfo[1]), "=c" (cpuinfo[2]), "=d" (cpuinfo[3]) : "0" (func), "2" (id));
+  #else
+    #define CPUID(cpuinfo,func,id) \
+      __asm__ __volatile__ ("cpuid": "=a" (cpuinfo[0]), "=b" (cpuinfo[1]), "=c" (cpuinfo[2]), "=d" (cpuinfo[3]) : "0" (func), "2" (id) );
+  #endif
 #endif
 
 //  Other

From 0b64902f23fad8349a07b2cd2e6cf17b64c67c77 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Thu, 14 Apr 2022 22:47:18 +0200
Subject: [PATCH 11/22] owl/configure: remove devmode cflags

They break the compilation with some c compilers. See https://github.com/owlbarn/owl/pull/609

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/owl/config/configure.ml | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 5a672e8d0..ce123a8ef 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -164,13 +164,6 @@ let get_expmode_cflags _c =
   if not enable_expmode then [] else [ "-flto" ]
 
 
-let get_devmode_cflags _c =
-  let enable_devmode = bgetenv "OWL_ENABLE_DEVMODE" in
-  if not enable_devmode
-  then [ "-Wno-logical-op-parentheses" ]
-  else [ "-Wall"; "-pedantic"; "-Wextra"; "-Wunused" ]
-
-
 let default_gcc_path =
   let p0 = "/usr/local/lib/gcc/7" in
   if Sys.file_exists p0 then [ "-L" ^ p0 ] else []
@@ -305,11 +298,10 @@ some details on how your openblas has been installed and the output of
       in
       (* configure compile options *)
       let cflags =
-        []
+        [ "-Wall"; "-pedantic"; "-Wextra"; "-Wunused" ]
         @ openblas_conf.cflags
         @ cblas_conf.cflags
         @ default_cflags c
-        @ get_devmode_cflags c
         @ get_expmode_cflags c
         @ openmp_config.cflags
       in

From 729cf0037e22caf2cca6b25a1ffdec20ae0e3112 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Thu, 28 Apr 2022 22:10:30 +0200
Subject: [PATCH 12/22] owl_core_utils: Fix empty elif

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/owl/core/owl_core_utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/owl/core/owl_core_utils.c b/src/owl/core/owl_core_utils.c
index ea36bf306..6b2f5b67a 100644
--- a/src/owl/core/owl_core_utils.c
+++ b/src/owl/core/owl_core_utils.c
@@ -213,7 +213,7 @@ void query_cache_sizes(int* l1p, int* l2p, int* l3p) {
   *l2p = 512 * 1024;
   *l3p = 512 * 1024;
 }
-#elif
+#else
 OWL_INLINE void query_cache_sizes_intel(int* l1p, int* l2p, int* l3p) {
   int cpuinfo[4];
   int l1 = 0, l2 = 0, l3 = 0;

From 2537f1b6701cc27880c48398953ef4419efe5448 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Fri, 29 Apr 2022 08:24:57 +0200
Subject: [PATCH 13/22] Cleanup arch detection code

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/aeos/config/configure.ml | 42 ++++++++++++++++++++++++------------
 src/owl/config/configure.ml  | 42 ++++++++++++++++++++++++------------
 2 files changed, 56 insertions(+), 28 deletions(-)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index 2d5bf398c..e3218a71b 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -25,6 +25,20 @@ let detect_system_header =
   #endif
 |}
 
+let detect_system_arch =
+  {|
+  #if __x86_64__
+    #define PLATFORM_ARCH "x86_64"
+  #elif __i386__
+    #define PLATFORM_ARCH "x86"
+  #elif __aarch64__
+    #define PLATFORM_ARCH "arm64"
+  #elif __arm__
+    #define PLATFORM_ARCH "arm"
+  #else
+    #define PLATFORM_ARCH "unknown"
+  #endif
+|}
 
 let bgetenv v =
   let v' =
@@ -73,21 +87,21 @@ let get_default_cflags c =
       | _                    -> `unknown
     in
     let arch =
-      let defines =
-        C.C_define.import
-          c
-          ~includes:[]
-          [ "__x86_64__", Switch
-          ; "__i386__", Switch
-          ; "__aarch64__", Switch
-          ; "__arm__", Switch
-          ]
+      let header =
+        let file = Filename.temp_file "discover" "arch.h" in
+        let fd = open_out file in
+        output_string fd detect_system_arch;
+        close_out fd;
+        file
+      in
+      let arch =
+        C.C_define.import c ~includes:[ header ] [ "PLATFORM_ARCH", String ]
       in
-      match List.map snd defines with
-      | Switch true :: _ -> `x86_64
-      | _ :: Switch true :: _ -> `x86
-      | _ :: _ :: Switch true :: _ -> `arm64
-      | _ :: _ :: _ :: Switch true :: _ -> `arm
+      match List.map snd arch with
+      | [ String "x86_64" ] -> `x86_64
+      | [ String "x86" ] -> `x86
+      | [ String "arm64" ] -> `arm64
+      | [ String "arm" ] -> `arm
       | _ -> `unknown
     in
     [ "-g"; "-O3"; "-Ofast" ]
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index ce123a8ef..cb13dda40 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -25,6 +25,20 @@ let detect_system_header =
   #endif
 |}
 
+let detect_system_arch =
+  {|
+  #if __x86_64__
+    #define PLATFORM_ARCH "x86_64"
+  #elif __i386__
+    #define PLATFORM_ARCH "x86"
+  #elif __aarch64__
+    #define PLATFORM_ARCH "arm64"
+  #elif __arm__
+    #define PLATFORM_ARCH "arm"
+  #else
+    #define PLATFORM_ARCH "unknown"
+  #endif
+|}
 
 let bgetenv v =
   let v' =
@@ -125,21 +139,21 @@ let default_cflags c =
       | _                    -> `unknown
     in
     let arch =
-      let defines =
-        C.C_define.import
-          c
-          ~includes:[]
-          [ "__x86_64__", Switch
-          ; "__i386__", Switch
-          ; "__aarch64__", Switch
-          ; "__arm__", Switch
-          ]
+      let header =
+        let file = Filename.temp_file "discover" "arch.h" in
+        let fd = open_out file in
+        output_string fd detect_system_arch;
+        close_out fd;
+        file
+      in
+      let arch =
+        C.C_define.import c ~includes:[ header ] [ "PLATFORM_ARCH", String ]
       in
-      match List.map snd defines with
-      | Switch true :: _ -> `x86_64
-      | _ :: Switch true :: _ -> `x86
-      | _ :: _ :: Switch true :: _ -> `arm64
-      | _ :: _ :: _ :: Switch true :: _ -> `arm
+      match List.map snd arch with
+      | [ String "x86_64" ] -> `x86_64
+      | [ String "x86" ] -> `x86
+      | [ String "arm64" ] -> `arm64
+      | [ String "arm" ] -> `arm
       | _ -> `unknown
     in
     [ (* Basic optimisation *) "-g"; "-O3"; "-Ofast" ]

From c9a67a415b10c4198c7863f2d3e280852cbbfe82 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Wed, 11 May 2022 14:52:35 +0200
Subject: [PATCH 14/22] configure: update to support new lapacke packages

Debian now ships lapacke separately, requiring new set of flags for the linking to work.
This uses pkg-config to improve the detection of these flags.

Furthermore this commit adds a workaround to solve the issue with libgcc11_s not found,
which will not be addressed upstream in homebrew for the time being.

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/owl/config/configure.ml | 141 ++++++++++++++++++++----------------
 1 file changed, 77 insertions(+), 64 deletions(-)

diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index cb13dda40..dceba1de2 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -111,64 +111,68 @@ let get_ocaml_devmode_flags _c =
   if not enable_devmode then [] else [ "-w"; "-32-27-6-37-3" ]
 
 
-let default_cflags c =
-  try
-    Sys.getenv "OWL_CFLAGS"
-    |> String.trim
-    |> String.split_on_char ' '
-    |> List.filter (fun s -> String.trim s <> "")
-  with
-  | Not_found ->
-    let os =
-      let header =
-        let file = Filename.temp_file "discover" "os.h" in
-        let fd = open_out file in
-        output_string fd detect_system_header;
-        close_out fd;
-        file
-      in
-      let platform =
-        C.C_define.import c ~includes:[ header ] [ "PLATFORM_NAME", String ]
-      in
-      match List.map snd platform with
-      | [ String "android" ] -> `android
-      | [ String "ios" ]     -> `ios
-      | [ String "linux" ]   -> `linux
-      | [ String "mac" ]     -> `mac
-      | [ String "windows" ] -> `windows
-      | _                    -> `unknown
+let default_config c =
+  let os =
+    let header =
+      let file = Filename.temp_file "discover" "os.h" in
+      let fd = open_out file in
+      output_string fd detect_system_header;
+      close_out fd;
+      file
     in
-    let arch =
-      let header =
-        let file = Filename.temp_file "discover" "arch.h" in
-        let fd = open_out file in
-        output_string fd detect_system_arch;
-        close_out fd;
-        file
-      in
-      let arch =
-        C.C_define.import c ~includes:[ header ] [ "PLATFORM_ARCH", String ]
-      in
-      match List.map snd arch with
-      | [ String "x86_64" ] -> `x86_64
-      | [ String "x86" ] -> `x86
-      | [ String "arm64" ] -> `arm64
-      | [ String "arm" ] -> `arm
-      | _ -> `unknown
+    let platform = C.C_define.import c ~includes:[ header ] [ "PLATFORM_NAME", String ] in
+    match List.map snd platform with
+    | [ String "android" ] -> `android
+    | [ String "ios" ]     -> `ios
+    | [ String "linux" ]   -> `linux
+    | [ String "mac" ]     -> `mac
+    | [ String "windows" ] -> `windows
+    | _                    -> `unknown
+  in
+  let arch =
+    let header =
+      let file = Filename.temp_file "discover" "arch.h" in
+      let fd = open_out file in
+      output_string fd detect_system_arch;
+      close_out fd;
+      file
     in
-    [ (* Basic optimisation *) "-g"; "-O3"; "-Ofast" ]
-    @ (match arch, os with
-      | `arm64, `mac -> [ "-mcpu=apple-m1" ]
-      | `arm64, _    -> [ "-march=native" ]
-      | `x86_64, _   -> [ "-march=native"; "-mfpmath=sse"; "-msse2" ]
-      | _            -> [])
-    @ [ (* Experimental switches, -ffast-math may break IEEE754 semantics*)
-        "-funroll-loops"
-      ; "-ffast-math"
-      ; (* Configure Mersenne Twister RNG *)
-        "-DSFMT_MEXP=19937"
-      ; "-fno-strict-aliasing"
-      ]
+    let arch = C.C_define.import c ~includes:[ header ] [ "PLATFORM_ARCH", String ] in
+    match List.map snd arch with
+    | [ String "x86_64" ] -> `x86_64
+    | [ String "x86" ] -> `x86
+    | [ String "arm64" ] -> `arm64
+    | [ String "arm" ] -> `arm
+    | _ -> `unknown
+  in
+  let cflags =
+    try
+      Sys.getenv "OWL_CFLAGS"
+      |> String.trim
+      |> String.split_on_char ' '
+      |> List.filter (fun s -> String.trim s <> "")
+    with
+    | Not_found ->
+      [ (* Basic optimisation *) "-g"; "-O3"; "-Ofast" ]
+      @ (match arch, os with
+        | `arm64, `mac -> [ "-mcpu=apple-m1" ]
+        | `arm64, _    -> [ "-march=native" ]
+        | `x86_64, _   -> [ "-march=native"; "-mfpmath=sse"; "-msse2" ]
+        | _            -> [])
+      @ [ (* Experimental switches, -ffast-math may break IEEE754 semantics*)
+          "-funroll-loops"
+        ; "-ffast-math"
+        ; (* Configure Mersenne Twister RNG *)
+          "-DSFMT_MEXP=19937"
+        ; "-fno-strict-aliasing"
+        ]
+  in
+  (* homebrew M1 issue workaround, works only if users use the default homebrew path *)
+  let libs =
+    let p0 = "/opt/homebrew/opt/gcc/lib/gcc/11/" in
+    if os = `mac && arch = `arm64 && Sys.file_exists p0 then [ "-L" ^ p0 ] else []
+  in
+  C.Pkg_config.{ cflags; libs }
 
 
 let default_libs = [ "-lm" ]
@@ -246,11 +250,12 @@ the output of `src/owl/config/configure.exe --verbose`.
 
 let () =
   C.main ~name:"owl" (fun c ->
+      let default_config = default_config c in
+      let default_pkg_config = { C.Pkg_config.cflags = []; libs = [] } in
       let cblas_conf =
-        let default = { C.Pkg_config.cflags = []; libs = [] } in
         let open Base.Option.Monad_infix in
         Base.Option.value
-          ~default
+          ~default:default_pkg_config
           (C.Pkg_config.get c >>= C.Pkg_config.query ~package:"cblas")
       in
       let openblas_conf =
@@ -264,7 +269,7 @@ let () =
               c
               test_linking
               ~c_flags:openblas_conf.cflags
-              ~link_flags:openblas_conf.libs
+              ~link_flags:(default_config.libs @ openblas_conf.libs)
       then (
         Printf.printf
           {|
@@ -283,7 +288,7 @@ some details on how your openblas has been installed and the output of
           Base.(Sexp.to_string @@ sexp_of_list sexp_of_string openblas_conf.cflags)
           Base.(Sexp.to_string @@ sexp_of_list sexp_of_string openblas_conf.libs);
         failwith "Unable to link against openblas.");
-      let lapacke_lib =
+      let lapacke_conf =
         let disable_linking_flag = bgetenv "OWL_DISABLE_LAPACKE_LINKING_FLAG" in
         let needs_lapacke_flag =
           if disable_linking_flag
@@ -293,16 +298,23 @@ some details on how your openblas has been installed and the output of
               c
               test_lapacke_working_code
               ~c_flags:openblas_conf.cflags
-              ~link_flags:(openblas_conf.libs @ [ "-lm" ])
+              ~link_flags:(default_config.libs @ openblas_conf.libs @ [ "-lm" ])
             |> not
         in
-        if needs_lapacke_flag then [ "-llapacke" ] else []
+        if needs_lapacke_flag
+        then
+          let open Base.Option.Monad_infix in
+          Base.Option.value
+            ~default:C.Pkg_config.{ cflags = []; libs = [ "-llapacke" ] }
+            (C.Pkg_config.get c >>= C.Pkg_config.query ~package:"llapacke")
+        else default_pkg_config
       in
       let openmp_config = get_openmp_config c in
       (* configure link options *)
       let libs =
         []
-        @ lapacke_lib
+        @ default_config.libs
+        @ lapacke_conf.libs
         @ openblas_conf.libs
         @ cblas_conf.libs
         @ default_libs
@@ -313,9 +325,10 @@ some details on how your openblas has been installed and the output of
       (* configure compile options *)
       let cflags =
         [ "-Wall"; "-pedantic"; "-Wextra"; "-Wunused" ]
+        @ lapacke_conf.cflags
         @ openblas_conf.cflags
         @ cblas_conf.cflags
-        @ default_cflags c
+        @ default_config.cflags
         @ get_expmode_cflags c
         @ openmp_config.cflags
       in

From 7924c344947048c45065e9753af31ac649b997aa Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Wed, 11 May 2022 14:58:50 +0200
Subject: [PATCH 15/22] ocamlformat the code

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/aeos/config/configure.ml | 14 +++++++-------
 src/owl/config/configure.ml  | 10 ++++++----
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index e3218a71b..1d467b136 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -25,6 +25,7 @@ let detect_system_header =
   #endif
 |}
 
+
 let detect_system_arch =
   {|
   #if __x86_64__
@@ -40,6 +41,7 @@ let detect_system_arch =
   #endif
 |}
 
+
 let bgetenv v =
   let v' =
     try Sys.getenv v |> int_of_string with
@@ -94,15 +96,13 @@ let get_default_cflags c =
         close_out fd;
         file
       in
-      let arch =
-        C.C_define.import c ~includes:[ header ] [ "PLATFORM_ARCH", String ]
-      in
+      let arch = C.C_define.import c ~includes:[ header ] [ "PLATFORM_ARCH", String ] in
       match List.map snd arch with
       | [ String "x86_64" ] -> `x86_64
-      | [ String "x86" ] -> `x86
-      | [ String "arm64" ] -> `arm64
-      | [ String "arm" ] -> `arm
-      | _ -> `unknown
+      | [ String "x86" ]    -> `x86
+      | [ String "arm64" ]  -> `arm64
+      | [ String "arm" ]    -> `arm
+      | _                   -> `unknown
     in
     [ "-g"; "-O3"; "-Ofast" ]
     @ (match arch, os with
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index dceba1de2..2475d9f85 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -25,6 +25,7 @@ let detect_system_header =
   #endif
 |}
 
+
 let detect_system_arch =
   {|
   #if __x86_64__
@@ -40,6 +41,7 @@ let detect_system_arch =
   #endif
 |}
 
+
 let bgetenv v =
   let v' =
     try Sys.getenv v |> int_of_string with
@@ -140,10 +142,10 @@ let default_config c =
     let arch = C.C_define.import c ~includes:[ header ] [ "PLATFORM_ARCH", String ] in
     match List.map snd arch with
     | [ String "x86_64" ] -> `x86_64
-    | [ String "x86" ] -> `x86
-    | [ String "arm64" ] -> `arm64
-    | [ String "arm" ] -> `arm
-    | _ -> `unknown
+    | [ String "x86" ]    -> `x86
+    | [ String "arm64" ]  -> `arm64
+    | [ String "arm" ]    -> `arm
+    | _                   -> `unknown
   in
   let cflags =
     try

From f9b875aa892a0b5e87cfac85437399355add23eb Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Sat, 14 May 2022 10:52:37 +0200
Subject: [PATCH 16/22] Workaround configurator problem with windows

And remove march=native from arm, since it breaks on a number of arm systems

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/aeos/config/configure.ml | 21 ++++-----------------
 src/owl/config/configure.ml  | 22 +++-------------------
 2 files changed, 7 insertions(+), 36 deletions(-)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index 1d467b136..36a62d455 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -5,7 +5,7 @@
 
 module C = Configurator.V1
 
-let detect_system_header =
+let detect_system_os =
   {|
   #if __APPLE__
     #include <TargetConditionals.h>
@@ -70,15 +70,8 @@ let get_default_cflags c =
   with
   | Not_found ->
     let os =
-      let header =
-        let file = Filename.temp_file "discover" "os.h" in
-        let fd = open_out file in
-        output_string fd detect_system_header;
-        close_out fd;
-        file
-      in
       let platform =
-        C.C_define.import c ~includes:[ header ] [ "PLATFORM_NAME", String ]
+        C.C_define.import c ~includes:[ ] ~prelude:detect_system_os [ "PLATFORM_NAME", String ]
       in
       match List.map snd platform with
       | [ String "android" ] -> `android
@@ -89,14 +82,9 @@ let get_default_cflags c =
       | _                    -> `unknown
     in
     let arch =
-      let header =
-        let file = Filename.temp_file "discover" "arch.h" in
-        let fd = open_out file in
-        output_string fd detect_system_arch;
-        close_out fd;
-        file
+      let arch =
+        C.C_define.import c ~includes:[ ] ~prelude:detect_system_arch [ "PLATFORM_ARCH", String ]
       in
-      let arch = C.C_define.import c ~includes:[ header ] [ "PLATFORM_ARCH", String ] in
       match List.map snd arch with
       | [ String "x86_64" ] -> `x86_64
       | [ String "x86" ]    -> `x86
@@ -107,7 +95,6 @@ let get_default_cflags c =
     [ "-g"; "-O3"; "-Ofast" ]
     @ (match arch, os with
       | `arm64, `mac -> [ "-mcpu=apple-m1" ]
-      | `arm64, _    -> [ "-march=native" ]
       | `x86_64, _   -> [ "-march=native"; "-msse2" ]
       | _            -> [])
     @ [ "-funroll-loops"; "-ffast-math"; "-DSFMT_MEXP=19937"; "-fno-strict-aliasing" ]
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 2475d9f85..9726c0bf5 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -5,7 +5,7 @@
 
 module C = Configurator.V1
 
-let detect_system_header =
+let detect_system_os =
   {|
   #if __APPLE__
     #include <TargetConditionals.h>
@@ -115,14 +115,7 @@ let get_ocaml_devmode_flags _c =
 
 let default_config c =
   let os =
-    let header =
-      let file = Filename.temp_file "discover" "os.h" in
-      let fd = open_out file in
-      output_string fd detect_system_header;
-      close_out fd;
-      file
-    in
-    let platform = C.C_define.import c ~includes:[ header ] [ "PLATFORM_NAME", String ] in
+    let platform = C.C_define.import c ~includes:[ ] ~prelude:detect_system_os [ "PLATFORM_NAME", String ] in
     match List.map snd platform with
     | [ String "android" ] -> `android
     | [ String "ios" ]     -> `ios
@@ -132,14 +125,7 @@ let default_config c =
     | _                    -> `unknown
   in
   let arch =
-    let header =
-      let file = Filename.temp_file "discover" "arch.h" in
-      let fd = open_out file in
-      output_string fd detect_system_arch;
-      close_out fd;
-      file
-    in
-    let arch = C.C_define.import c ~includes:[ header ] [ "PLATFORM_ARCH", String ] in
+    let arch = C.C_define.import c ~includes:[ ] ~prelude:detect_system_arch [ "PLATFORM_ARCH", String ] in
     match List.map snd arch with
     | [ String "x86_64" ] -> `x86_64
     | [ String "x86" ]    -> `x86
@@ -158,7 +144,6 @@ let default_config c =
       [ (* Basic optimisation *) "-g"; "-O3"; "-Ofast" ]
       @ (match arch, os with
         | `arm64, `mac -> [ "-mcpu=apple-m1" ]
-        | `arm64, _    -> [ "-march=native" ]
         | `x86_64, _   -> [ "-march=native"; "-mfpmath=sse"; "-msse2" ]
         | _            -> [])
       @ [ (* Experimental switches, -ffast-math may break IEEE754 semantics*)
@@ -176,7 +161,6 @@ let default_config c =
   in
   C.Pkg_config.{ cflags; libs }
 
-
 let default_libs = [ "-lm" ]
 
 let get_expmode_cflags _c =

From c575988392993a128e934c7c0c2cb2f73570b5e7 Mon Sep 17 00:00:00 2001
From: Marcello Seri <mseri@users.noreply.github.com>
Date: Thu, 2 Jun 2022 22:23:07 +0200
Subject: [PATCH 17/22] configurator: make more robust wrt not officially
 supported platforms (e.g. bsds)

---
 src/aeos/config/configure.ml | 2 ++
 src/owl/config/configure.ml  | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index 36a62d455..0fdd25f9e 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -22,6 +22,8 @@ let detect_system_os =
     #endif
   #elif WIN32
     #define PLATFORM_NAME "windows"
+  #else
+    #define PLATFORM_NAME "unknown"
   #endif
 |}
 
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 9726c0bf5..fc59efd15 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -22,6 +22,8 @@ let detect_system_os =
     #endif
   #elif WIN32
     #define PLATFORM_NAME "windows"
+  #else
+    #define PLATFORM_NAME "unknown"
   #endif
 |}
 

From 954f498432198cea2f61612350907992c55747dc Mon Sep 17 00:00:00 2001
From: Marcello Seri <mseri@users.noreply.github.com>
Date: Sat, 8 Oct 2022 16:05:44 +0200
Subject: [PATCH 18/22] Update src/owl/config/configure.ml

Co-authored-by: Thomas Gazagnaire <thomas@gazagnaire.org>
---
 src/owl/config/configure.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index fc59efd15..22a82a883 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -158,7 +158,7 @@ let default_config c =
   in
   (* homebrew M1 issue workaround, works only if users use the default homebrew path *)
   let libs =
-    let p0 = "/opt/homebrew/opt/gcc/lib/gcc/11/" in
+    let p0 = "/opt/homebrew/opt/gcc/lib/gcc/current/" in
     if os = `mac && arch = `arm64 && Sys.file_exists p0 then [ "-L" ^ p0 ] else []
   in
   C.Pkg_config.{ cflags; libs }

From 00e9d3331ee20e587b7d8e9883d0c5f27944fec7 Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Mon, 9 Jan 2023 10:26:08 +0100
Subject: [PATCH 19/22] configurator: drop unnecessary dependency on stdio

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 owl.opam                    |  1 -
 src/aeos/config/dune        |  2 +-
 src/owl/config/configure.ml | 23 ++++++++++-------------
 src/owl/config/dune         |  2 +-
 4 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/owl.opam b/owl.opam
index 2a44f3871..de6ba7652 100644
--- a/owl.opam
+++ b/owl.opam
@@ -32,6 +32,5 @@ depends: [
   "dune-configurator"
   "eigen" {>= "0.3.0"}
   "owl-base" {= version}
-  "stdio" {build}
   "npy"
 ]
diff --git a/src/aeos/config/dune b/src/aeos/config/dune
index a9a6574c7..cb623703a 100644
--- a/src/aeos/config/dune
+++ b/src/aeos/config/dune
@@ -1,3 +1,3 @@
 (executable
  (name configure)
- (libraries dune.configurator stdio))
+ (libraries dune.configurator))
diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 22a82a883..a4151c2a2 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -220,7 +220,7 @@ let get_openmp_config c =
         {|
 You have set OWL_ENABLE_OPENMP = 1 however I am unable to link
 against openmp: the current values for cflags and libs are respectively
-%s and %s.
+(%s) and (%s).
 
 You can disable openmp/aeos by unsetting OWL_ENABLE_OPEN or by setting
 it to 0.
@@ -230,25 +230,23 @@ or `dune clean` before rebuilding the project with a modified flag.
 If you think this is our mistake please open an issue reporting
 the output of `src/owl/config/configure.exe --verbose`.
 |}
-        Base.(string_of_sexp @@ sexp_of_list sexp_of_string cflags)
-        Base.(string_of_sexp @@ sexp_of_list sexp_of_string libs);
+        (String.concat " " cflags)
+        (String.concat " " libs);
       failwith "Unable to link against openmp");
     C.Pkg_config.{ cflags; libs })
 
 
 let () =
   C.main ~name:"owl" (fun c ->
+      let (>>=) = Option.bind in
       let default_config = default_config c in
       let default_pkg_config = { C.Pkg_config.cflags = []; libs = [] } in
       let cblas_conf =
-        let open Base.Option.Monad_infix in
-        Base.Option.value
-          ~default:default_pkg_config
+        Option.value ~default:default_pkg_config
           (C.Pkg_config.get c >>= C.Pkg_config.query ~package:"cblas")
       in
       let openblas_conf =
-        let open Base.Option.Monad_infix in
-        Base.Option.value
+        Option.value
           ~default:openblas_default
           (C.Pkg_config.get c >>= C.Pkg_config.query ~package:"openblas")
       in
@@ -262,7 +260,7 @@ let () =
         Printf.printf
           {|
 Unable to link against openblas: the current values for cflags and libs
-are respectively %s and %s.
+are respectively (%s) and (%s).
 
 Usually this is due to missing paths for pkg-config. Try to re-install
 or re-compile owl by prefixing the command with (or exporting)
@@ -273,8 +271,8 @@ If this does not work please open an issue in the owl repository, adding
 some details on how your openblas has been installed and the output of
 `src/owl/config/configure.exe --verbose`.
 |}
-          Base.(Sexp.to_string @@ sexp_of_list sexp_of_string openblas_conf.cflags)
-          Base.(Sexp.to_string @@ sexp_of_list sexp_of_string openblas_conf.libs);
+        (String.concat " " openblas_conf.cflags)
+        (String.concat " " openblas_conf.libs);
         failwith "Unable to link against openblas.");
       let lapacke_conf =
         let disable_linking_flag = bgetenv "OWL_DISABLE_LAPACKE_LINKING_FLAG" in
@@ -291,8 +289,7 @@ some details on how your openblas has been installed and the output of
         in
         if needs_lapacke_flag
         then
-          let open Base.Option.Monad_infix in
-          Base.Option.value
+          Option.value
             ~default:C.Pkg_config.{ cflags = []; libs = [ "-llapacke" ] }
             (C.Pkg_config.get c >>= C.Pkg_config.query ~package:"llapacke")
         else default_pkg_config
diff --git a/src/owl/config/dune b/src/owl/config/dune
index a9a6574c7..cb623703a 100644
--- a/src/owl/config/dune
+++ b/src/owl/config/dune
@@ -1,3 +1,3 @@
 (executable
  (name configure)
- (libraries dune.configurator stdio))
+ (libraries dune.configurator))

From fac592767cde07dc1421677006ec73202b7ad8fa Mon Sep 17 00:00:00 2001
From: Marcello Seri <marcello.seri@gmail.com>
Date: Fri, 27 Oct 2023 10:31:38 +0200
Subject: [PATCH 20/22] add @jcreinhold patch for nonstandard setups

See https://github.com/owlbarn/owl/pull/636

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>
---
 src/owl/config/configure.ml | 89 ++++++++++++++++++++++---------------
 1 file changed, 52 insertions(+), 37 deletions(-)

diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index 5ef8d4957..e908c2032 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -110,12 +110,20 @@ let get_os_type c =
 
 let get_ocaml_default_flags _c = []
 
+
 let get_ocaml_devmode_flags _c =
   let enable_devmode = bgetenv "OWL_ENABLE_DEVMODE" in
   if not enable_devmode then [] else [ "-w"; "-32-27-6-37-3" ]
 
 
-let default_config c =
+let clean_env_var env_var =
+  Sys.getenv env_var
+    |> String.trim
+    |> String.split_on_char ' '
+    |> List.filter (fun s -> String.trim s <> "")
+
+
+let get_default_config c =
   let os =
     let platform = C.C_define.import c ~includes:[ ] ~prelude:detect_system_os [ "PLATFORM_NAME", String ] in
     match List.map snd platform with
@@ -136,12 +144,7 @@ let default_config c =
     | _                   -> `unknown
   in
   let cflags =
-    try
-      Sys.getenv "OWL_CFLAGS"
-      |> String.trim
-      |> String.split_on_char ' '
-      |> List.filter (fun s -> String.trim s <> "")
-    with
+    try clean_env_var "OWL_CFLAGS" with
     | Not_found ->
       [ (* Basic optimisation *) "-g"; "-O3"; "-Ofast" ]
       @ (match arch, os with
@@ -163,7 +166,21 @@ let default_config c =
   in
   C.Pkg_config.{ cflags; libs }
 
-let default_libs = [ "-lm" ]
+
+let default_cppflags =
+  try clean_env_var "OWL_CPPFLAGS" with
+    | Not_found -> []
+
+
+let default_ldflags =
+  try clean_env_var "OWL_LDFLAGS" with
+    | Not_found -> []
+
+
+let default_ldlibs =
+  try clean_env_var "OWL_LDLIBS" with
+    | Not_found -> [ "-lm" ]
+
 
 let get_expmode_cflags _c =
   let enable_expmode = bgetenv "OWL_ENABLE_EXPMODE" in
@@ -239,7 +256,7 @@ the output of `src/owl/config/configure.exe --verbose`.
 let () =
   C.main ~name:"owl" (fun c ->
       let (>>=) = Option.bind in
-      let default_config = default_config c in
+      let default_config = get_default_config c in
       let default_pkg_config = { C.Pkg_config.cflags = []; libs = [] } in
       let cblas_conf =
         Option.value ~default:default_pkg_config
@@ -250,12 +267,30 @@ let () =
           ~default:openblas_default
           (C.Pkg_config.get c >>= C.Pkg_config.query ~package:"openblas")
       in
-      if not
-         @@ C.c_test
-              c
-              test_linking
-              ~c_flags:openblas_conf.cflags
-              ~link_flags:(default_config.libs @ openblas_conf.libs)
+      let openmp_config = get_openmp_config c in
+      (* configure link options *)
+      let libs =
+        []
+        @ default_ldflags
+        @ default_ldlibs
+        @ default_config.libs
+        @ openblas_conf.libs
+        @ cblas_conf.libs
+        @ default_gcc_path
+        @ get_accelerate_libs c
+        @ openmp_config.libs
+      in
+      (* configure compile options *)
+      let cflags =
+        []
+        @ default_config.cflags
+        @ default_cppflags
+        @ openblas_conf.cflags
+        @ cblas_conf.cflags
+        @ get_expmode_cflags c
+        @ openmp_config.cflags
+      in
+      if not @@ C.c_test c test_linking ~c_flags:cflags ~link_flags:libs
       then (
         Printf.printf
           {|
@@ -294,29 +329,9 @@ some details on how your openblas has been installed and the output of
             (C.Pkg_config.get c >>= C.Pkg_config.query ~package:"llapacke")
         else default_pkg_config
       in
-      let openmp_config = get_openmp_config c in
       (* configure link options *)
-      let libs =
-        []
-        @ default_config.libs
-        @ lapacke_conf.libs
-        @ openblas_conf.libs
-        @ cblas_conf.libs
-        @ default_libs
-        @ default_gcc_path
-        @ get_accelerate_libs c
-        @ openmp_config.libs
-      in
-      (* configure compile options *)
-      let cflags =
-        [ "-Wall"; "-pedantic"; "-Wextra"; "-Wunused" ]
-        @ lapacke_conf.cflags
-        @ openblas_conf.cflags
-        @ cblas_conf.cflags
-        @ default_config.cflags
-        @ get_expmode_cflags c
-        @ openmp_config.cflags
-      in
+      let libs = lapacke_conf.libs @ libs in
+      let cflags = lapacke_conf.cflags @ cflags in 
       (* configure ocaml options *)
       let ocaml_flags = [] @ get_ocaml_default_flags c @ get_ocaml_devmode_flags c in
       (* assemble default config *)

From 882021186c222a881c8b956715ab9d9c274c581b Mon Sep 17 00:00:00 2001
From: Marcello Seri <mseri@users.noreply.github.com>
Date: Tue, 31 Oct 2023 22:56:04 +0100
Subject: [PATCH 21/22] Update src/aeos/config/configure.ml

---
 src/aeos/config/configure.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/aeos/config/configure.ml b/src/aeos/config/configure.ml
index b028fcb4f..24549ef9f 100644
--- a/src/aeos/config/configure.ml
+++ b/src/aeos/config/configure.ml
@@ -96,7 +96,7 @@ let get_default_cflags c =
     in
     [ "-g"; "-O3"; "-Ofast" ]
     @ (match arch, os with
-      | `arm64, `mac -> [ "-mcpu=apple-m1" ]
+      | `arm64, `mac -> [ "-march=native" ]
       | `x86_64, _   -> [ "-march=native"; "-msse2" ]
       | _            -> [])
     @ [ "-funroll-loops"; "-ffast-math"; "-DSFMT_MEXP=19937"; "-fno-strict-aliasing" ]

From d3b5390531a05b2a74754f46625a7f4d1efdb9b7 Mon Sep 17 00:00:00 2001
From: Marcello Seri <mseri@users.noreply.github.com>
Date: Tue, 31 Oct 2023 22:56:26 +0100
Subject: [PATCH 22/22] Update src/owl/config/configure.ml

---
 src/owl/config/configure.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/owl/config/configure.ml b/src/owl/config/configure.ml
index e908c2032..18b12a70a 100644
--- a/src/owl/config/configure.ml
+++ b/src/owl/config/configure.ml
@@ -148,7 +148,7 @@ let get_default_config c =
     | Not_found ->
       [ (* Basic optimisation *) "-g"; "-O3"; "-Ofast" ]
       @ (match arch, os with
-        | `arm64, `mac -> [ "-mcpu=apple-m1" ]
+        | `arm64, `mac -> [ "-march=native" ]
         | `x86_64, _   -> [ "-march=native"; "-mfpmath=sse"; "-msse2" ]
         | _            -> [])
       @ [ (* Experimental switches, -ffast-math may break IEEE754 semantics*)