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Make have_fma consistent between interpreter and compiled (#52206)
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Currently the interpreter always returns false. Which isn't very good.
Make it follow whatever the JIT will do.
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gbaraldi authored Nov 21, 2023
1 parent 0402c78 commit a6c656e
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Showing 9 changed files with 49 additions and 5 deletions.
1 change: 1 addition & 0 deletions src/jl_exported_funcs.inc
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Expand Up @@ -200,6 +200,7 @@
XX(jl_get_binding_wr) \
XX(jl_get_cpu_name) \
XX(jl_get_cpu_features) \
XX(jl_cpu_has_fma) \
XX(jl_get_current_task) \
XX(jl_get_default_sysimg_path) \
XX(jl_get_excstack) \
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4 changes: 2 additions & 2 deletions src/llvm-cpufeatures.cpp
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Expand Up @@ -59,15 +59,15 @@ static bool have_fma(Function &intr, Function &caller, const Triple &TT) JL_NOTS
StringRef FS =
FSAttr.isValid() ? FSAttr.getValueAsString() : jl_ExecutionEngine->getTargetFeatureString();

SmallVector<StringRef, 6> Features;
SmallVector<StringRef, 128> Features;
FS.split(Features, ',');
for (StringRef Feature : Features)
if (TT.isARM()) {
if (Feature == "+vfp4")
return typ == "f32" || typ == "f64";
else if (Feature == "+vfp4sp")
return typ == "f32";
} else {
} else if (TT.isX86()) {
if (Feature == "+fma" || Feature == "+fma4")
return typ == "f32" || typ == "f64";
}
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2 changes: 2 additions & 0 deletions src/processor.h
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Expand Up @@ -226,6 +226,8 @@ JL_DLLEXPORT jl_value_t *jl_get_cpu_name(void);
// Return the features of the host CPU as a julia string.
JL_DLLEXPORT jl_value_t *jl_get_cpu_features(void);
// Dump the name and feature set of the host CPU
JL_DLLEXPORT jl_value_t *jl_cpu_has_fma(int bits);
// Check if the CPU has native FMA instructions;
// For debugging only
JL_DLLEXPORT void jl_dump_host_cpu(void);
JL_DLLEXPORT jl_value_t* jl_check_pkgimage_clones(char* data);
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16 changes: 16 additions & 0 deletions src/processor_arm.cpp
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Expand Up @@ -1808,6 +1808,22 @@ JL_DLLEXPORT jl_value_t *jl_get_cpu_features(void)
return jl_cstr_to_string(jl_get_cpu_features_llvm().c_str());
}

JL_DLLEXPORT jl_value_t *jl_cpu_has_fma(int bits)
{
#ifdef _CPU_AARCH64_
return jl_true;
#else
TargetData<feature_sz> target = jit_targets.front();
FeatureList<feature_sz> features = target.en.features;
if (bits == 32 && test_nbit(features, Feature::vfp4sp))
return jl_true;
else if ((bits == 64 || bits == 32) && test_nbit(features, Feature::vfp4))
return jl_true;
else
return jl_false;
#endif
}

jl_image_t jl_init_processor_sysimg(void *hdl)
{
if (!jit_targets.empty())
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5 changes: 5 additions & 0 deletions src/processor_fallback.cpp
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Expand Up @@ -172,6 +172,11 @@ JL_DLLEXPORT jl_value_t *jl_get_cpu_features(void)
return jl_cstr_to_string(jl_get_cpu_features_llvm().c_str());
}

JL_DLLEXPORT jl_value_t *jl_cpu_has_fma(int bits)
{
return jl_false; // Match behaviour of have_fma in src/llvm-cpufeatures.cpp (assume false)
}

JL_DLLEXPORT void jl_dump_host_cpu(void)
{
jl_safe_printf("CPU: %s\n", host_cpu_name().c_str());
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11 changes: 11 additions & 0 deletions src/processor_x86.cpp
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Expand Up @@ -4,6 +4,7 @@

// CPUID

#include "julia.h"
extern "C" JL_DLLEXPORT void jl_cpuid(int32_t CPUInfo[4], int32_t InfoType)
{
asm volatile (
Expand Down Expand Up @@ -1062,6 +1063,16 @@ JL_DLLEXPORT jl_value_t *jl_get_cpu_features(void)
return jl_cstr_to_string(jl_get_cpu_features_llvm().c_str());
}

JL_DLLEXPORT jl_value_t *jl_cpu_has_fma(int bits)
{
TargetData<feature_sz> target = jit_targets.front();
FeatureList<feature_sz> features = target.en.features;
if ((bits == 32 || bits == 64) && (test_nbit(features, Feature::fma) || test_nbit(features, Feature::fma4)))
return jl_true;
else
return jl_false;
}

jl_image_t jl_init_processor_sysimg(void *hdl)
{
if (!jit_targets.empty())
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11 changes: 8 additions & 3 deletions src/runtime_intrinsics.c
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Expand Up @@ -1671,10 +1671,15 @@ un_fintrinsic(trunc_float,trunc_llvm)
un_fintrinsic(rint_float,rint_llvm)
un_fintrinsic(sqrt_float,sqrt_llvm)
un_fintrinsic(sqrt_float,sqrt_llvm_fast)
jl_value_t *jl_cpu_has_fma(int bits);

JL_DLLEXPORT jl_value_t *jl_have_fma(jl_value_t *typ)
{
JL_TYPECHK(have_fma, datatype, typ);
// TODO: run-time feature check?
return jl_false;
JL_TYPECHK(have_fma, datatype, typ); // TODO what about float16/bfloat16?
if (typ == (jl_value_t*)jl_float32_type)
return jl_cpu_has_fma(32);
else if (typ == (jl_value_t*)jl_float64_type)
return jl_cpu_has_fma(64);
else
return jl_false;
}
2 changes: 2 additions & 0 deletions test/llvmpasses/cpu-features.ll
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Expand Up @@ -3,6 +3,8 @@
; RUN: opt -enable-new-pm=1 --opaque-pointers=0 --load-pass-plugin=libjulia-codegen%shlibext -passes='CPUFeatures,simplifycfg' -S %s | FileCheck %s

; RUN: opt -enable-new-pm=1 --opaque-pointers=1 --load-pass-plugin=libjulia-codegen%shlibext -passes='CPUFeatures,simplifycfg' -S %s | FileCheck %s
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:10:11:12:13"
target triple = "x86_64-linux-gnu"

declare i1 @julia.cpu.have_fma.f64()
declare double @with_fma(double %0, double %1, double %2)
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2 changes: 2 additions & 0 deletions test/sysinfo.jl
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Expand Up @@ -12,6 +12,8 @@ Base.Sys.loadavg()

@test length(ccall(:jl_get_cpu_name, String, ())) != 0
@test length(ccall(:jl_get_cpu_features, String, ())) >= 0
foo_fma() = Core.Intrinsics.have_fma(Int64)
@test ccall(:jl_cpu_has_fma, Bool, (Cint,), 64) == foo_fma()

if Sys.isunix()
mktempdir() do tempdir
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