From 699240567446ba9d794b7e4883831ae13aadac59 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 19 Sep 2023 19:20:22 +0000
Subject: [PATCH 1/2] Tolerate non-ptr indirect scalars in codegen.

---
 compiler/rustc_codegen_ssa/src/mir/operand.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_codegen_ssa/src/mir/operand.rs b/compiler/rustc_codegen_ssa/src/mir/operand.rs
index 9205acc527e53..63de6a7207284 100644
--- a/compiler/rustc_codegen_ssa/src/mir/operand.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/operand.rs
@@ -156,7 +156,7 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
             Abi::Scalar(s @ abi::Scalar::Initialized { .. }) => {
                 let size = s.size(bx);
                 assert_eq!(size, layout.size, "abi::Scalar size does not match layout size");
-                let val = read_scalar(Size::ZERO, size, s, bx.type_ptr());
+                let val = read_scalar(Size::ZERO, size, s, bx.backend_type(layout));
                 OperandRef { val: OperandValue::Immediate(val), layout }
             }
             Abi::ScalarPair(

From ac0683b78310bba9c3c601cfd81bbda4a10be322 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Sat, 23 Sep 2023 09:35:44 +0000
Subject: [PATCH 2/2] Use correct offset when codegening mir::Const::Indirect.

---
 compiler/rustc_codegen_ssa/src/mir/operand.rs | 23 +++++++++----------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/compiler/rustc_codegen_ssa/src/mir/operand.rs b/compiler/rustc_codegen_ssa/src/mir/operand.rs
index 63de6a7207284..0ab2b7ecd9c80 100644
--- a/compiler/rustc_codegen_ssa/src/mir/operand.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/operand.rs
@@ -135,15 +135,14 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
         assert_eq!(alloc_align, layout.align.abi);
 
         let read_scalar = |start, size, s: abi::Scalar, ty| {
-            let val = alloc
-                .0
-                .read_scalar(
-                    bx,
-                    alloc_range(start, size),
-                    /*read_provenance*/ matches!(s.primitive(), abi::Pointer(_)),
-                )
-                .unwrap();
-            bx.scalar_to_backend(val, s, ty)
+            match alloc.0.read_scalar(
+                bx,
+                alloc_range(start, size),
+                /*read_provenance*/ matches!(s.primitive(), abi::Pointer(_)),
+            ) {
+                Ok(val) => bx.scalar_to_backend(val, s, ty),
+                Err(_) => bx.const_poison(ty),
+            }
         };
 
         // It may seem like all types with `Scalar` or `ScalarPair` ABI are fair game at this point.
@@ -156,7 +155,7 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
             Abi::Scalar(s @ abi::Scalar::Initialized { .. }) => {
                 let size = s.size(bx);
                 assert_eq!(size, layout.size, "abi::Scalar size does not match layout size");
-                let val = read_scalar(Size::ZERO, size, s, bx.backend_type(layout));
+                let val = read_scalar(offset, size, s, bx.backend_type(layout));
                 OperandRef { val: OperandValue::Immediate(val), layout }
             }
             Abi::ScalarPair(
@@ -164,10 +163,10 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
                 b @ abi::Scalar::Initialized { .. },
             ) => {
                 let (a_size, b_size) = (a.size(bx), b.size(bx));
-                let b_offset = a_size.align_to(b.align(bx).abi);
+                let b_offset = (offset + a_size).align_to(b.align(bx).abi);
                 assert!(b_offset.bytes() > 0);
                 let a_val = read_scalar(
-                    Size::ZERO,
+                    offset,
                     a_size,
                     a,
                     bx.scalar_pair_element_backend_type(layout, 0, true),