https://github.com/MDevereau created
https://github.com/llvm/llvm-project/pull/137624
…eatures
The "target-features" function attribute is not currently considered when
adding vscale_range to a function. When +sve is pushed onto functions with
"#pragma attribute push(+sve)", the function potentially misses out on
optimizations that rely on vscale_range being present.
>From 9bed3ae2f1bb98fc6f53a17cca98da4b1562e1a7 Mon Sep 17 00:00:00 2001
From: Matthew Devereau <matthew.dever...@arm.com>
Date: Wed, 23 Apr 2025 12:27:02 +0000
Subject: [PATCH] [Clang][AArch64] Add pessimistic vscale_range when sve is in
target-features
The "target-features" function attribute is not currently considered when
adding vscale_range to a function. When +sve is pushed onto functions with
"#pragma attribute push(+sve)", the function potentially misses out on
optimizations that rely on vscale_range being present.
---
clang/include/clang/Basic/TargetInfo.h | 5 +++--
clang/lib/Basic/Targets/AArch64.cpp | 11 ++++++++++-
clang/lib/Basic/Targets/AArch64.h | 8 ++++++--
clang/lib/Basic/Targets/RISCV.cpp | 3 ++-
clang/lib/Basic/Targets/RISCV.h | 8 ++++++--
clang/lib/CodeGen/CodeGenFunction.cpp | 2 +-
.../test/CodeGen/AArch64/cpu-supports-target.c | 2 +-
clang/test/CodeGen/AArch64/targetattr.c | 18 +++++++++---------
8 files changed, 38 insertions(+), 19 deletions(-)
diff --git a/clang/include/clang/Basic/TargetInfo.h
b/clang/include/clang/Basic/TargetInfo.h
index 8c3dcda25bc8d..ba24f2aebcf5b 100644
--- a/clang/include/clang/Basic/TargetInfo.h
+++ b/clang/include/clang/Basic/TargetInfo.h
@@ -48,6 +48,7 @@
namespace llvm {
struct fltSemantics;
+class Function;
}
namespace clang {
@@ -1037,8 +1038,8 @@ class TargetInfo : public TransferrableTargetInfo,
/// Returns target-specific min and max values VScale_Range.
virtual std::optional<std::pair<unsigned, unsigned>>
- getVScaleRange(const LangOptions &LangOpts,
- bool IsArmStreamingFunction) const {
+ getVScaleRange(const LangOptions &LangOpts, bool IsArmStreamingFunction,
+ llvm::Function *F = nullptr) const {
return std::nullopt;
}
/// The __builtin_clz* and __builtin_ctz* built-in
diff --git a/clang/lib/Basic/Targets/AArch64.cpp
b/clang/lib/Basic/Targets/AArch64.cpp
index 3633bab6e0df9..045df30e6c77a 100644
--- a/clang/lib/Basic/Targets/AArch64.cpp
+++ b/clang/lib/Basic/Targets/AArch64.cpp
@@ -19,6 +19,7 @@
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSwitch.h"
+#include "llvm/IR/Function.h"
#include "llvm/TargetParser/AArch64TargetParser.h"
#include "llvm/TargetParser/ARMTargetParserCommon.h"
#include <optional>
@@ -794,7 +795,8 @@ AArch64TargetInfo::getTargetBuiltins() const {
std::optional<std::pair<unsigned, unsigned>>
AArch64TargetInfo::getVScaleRange(const LangOptions &LangOpts,
- bool IsArmStreamingFunction) const {
+ bool IsArmStreamingFunction,
+ llvm::Function *F) const {
if (LangOpts.VScaleMin || LangOpts.VScaleMax)
return std::pair<unsigned, unsigned>(
LangOpts.VScaleMin ? LangOpts.VScaleMin : 1, LangOpts.VScaleMax);
@@ -802,6 +804,13 @@ AArch64TargetInfo::getVScaleRange(const LangOptions
&LangOpts,
if (hasFeature("sve") || (IsArmStreamingFunction && hasFeature("sme")))
return std::pair<unsigned, unsigned>(1, 16);
+ if (F && F->hasFnAttribute("target-features")) {
+ StringRef Str = F->getFnAttribute("target-features").getValueAsString();
+ for (const auto &s : llvm::split(Str, ",")) {
+ if (s == "+sve")
+ return std::pair<unsigned, unsigned>(1, 16);
+ }
+ }
return std::nullopt;
}
diff --git a/clang/lib/Basic/Targets/AArch64.h
b/clang/lib/Basic/Targets/AArch64.h
index 2fab88cfca901..eb9fc24e51638 100644
--- a/clang/lib/Basic/Targets/AArch64.h
+++ b/clang/lib/Basic/Targets/AArch64.h
@@ -18,6 +18,10 @@
#include "llvm/TargetParser/AArch64TargetParser.h"
#include <optional>
+namespace llvm {
+class Function;
+}
+
namespace clang {
namespace targets {
@@ -187,8 +191,8 @@ class LLVM_LIBRARY_VISIBILITY AArch64TargetInfo : public
TargetInfo {
llvm::SmallVector<Builtin::InfosShard> getTargetBuiltins() const override;
std::optional<std::pair<unsigned, unsigned>>
- getVScaleRange(const LangOptions &LangOpts,
- bool IsArmStreamingFunction) const override;
+ getVScaleRange(const LangOptions &LangOpts, bool IsArmStreamingFunction,
+ llvm::Function *F = nullptr) const override;
bool doesFeatureAffectCodeGen(StringRef Name) const override;
bool validateCpuSupports(StringRef FeatureStr) const override;
bool hasFeature(StringRef Feature) const override;
diff --git a/clang/lib/Basic/Targets/RISCV.cpp
b/clang/lib/Basic/Targets/RISCV.cpp
index 390ef0f3ac884..95211cc7c5554 100644
--- a/clang/lib/Basic/Targets/RISCV.cpp
+++ b/clang/lib/Basic/Targets/RISCV.cpp
@@ -332,7 +332,8 @@ bool RISCVTargetInfo::initFeatureMap(
std::optional<std::pair<unsigned, unsigned>>
RISCVTargetInfo::getVScaleRange(const LangOptions &LangOpts,
- bool IsArmStreamingFunction) const {
+ bool IsArmStreamingFunction,
+ llvm::Function *F) const {
// RISCV::RVVBitsPerBlock is 64.
unsigned VScaleMin = ISAInfo->getMinVLen() / llvm::RISCV::RVVBitsPerBlock;
diff --git a/clang/lib/Basic/Targets/RISCV.h b/clang/lib/Basic/Targets/RISCV.h
index c26aa19080162..b072ccfe28ac4 100644
--- a/clang/lib/Basic/Targets/RISCV.h
+++ b/clang/lib/Basic/Targets/RISCV.h
@@ -20,6 +20,10 @@
#include "llvm/TargetParser/Triple.h"
#include <optional>
+namespace llvm {
+class Function;
+}
+
namespace clang {
namespace targets {
@@ -99,8 +103,8 @@ class RISCVTargetInfo : public TargetInfo {
const std::vector<std::string> &FeaturesVec) const override;
std::optional<std::pair<unsigned, unsigned>>
- getVScaleRange(const LangOptions &LangOpts,
- bool IsArmStreamingFunction) const override;
+ getVScaleRange(const LangOptions &LangOpts, bool IsArmStreamingFunction,
+ llvm::Function *F = nullptr) const override;
bool hasFeature(StringRef Feature) const override;
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp
b/clang/lib/CodeGen/CodeGenFunction.cpp
index 4d29ceace646f..e9b1231e79289 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1117,7 +1117,7 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
QualType RetTy,
// Add vscale_range attribute if appropriate.
std::optional<std::pair<unsigned, unsigned>> VScaleRange =
getContext().getTargetInfo().getVScaleRange(
- getLangOpts(), FD ? IsArmStreamingFunction(FD, true) : false);
+ getLangOpts(), FD ? IsArmStreamingFunction(FD, true) : false, CurFn);
if (VScaleRange) {
CurFn->addFnAttr(llvm::Attribute::getWithVScaleRangeArgs(
getLLVMContext(), VScaleRange->first, VScaleRange->second));
diff --git a/clang/test/CodeGen/AArch64/cpu-supports-target.c
b/clang/test/CodeGen/AArch64/cpu-supports-target.c
index a39ffd4e4a74d..9b551a0714e74 100644
--- a/clang/test/CodeGen/AArch64/cpu-supports-target.c
+++ b/clang/test/CodeGen/AArch64/cpu-supports-target.c
@@ -220,7 +220,7 @@ int test_versions() {
//.
// CHECK: attributes #[[ATTR0]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8" }
// CHECK: attributes #[[ATTR1]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+fp-armv8,+neon" }
-// CHECK: attributes #[[ATTR2]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+fp-armv8,+fullfp16,+sve" }
+// CHECK: attributes #[[ATTR2]] = { noinline nounwind optnone
vscale_range(1,16) "no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+fp-armv8,+fullfp16,+sve" }
//.
// CHECK: [[META0:![0-9]+]] = !{i32 1, !"wchar_size", i32 4}
// CHECK: [[META1:![0-9]+]] = !{!"{{.*}}clang version {{.*}}"}
diff --git a/clang/test/CodeGen/AArch64/targetattr.c
b/clang/test/CodeGen/AArch64/targetattr.c
index cfe115bf97ed3..7052f2917cf71 100644
--- a/clang/test/CodeGen/AArch64/targetattr.c
+++ b/clang/test/CodeGen/AArch64/targetattr.c
@@ -201,21 +201,21 @@ void applem4() {}
//.
// CHECK: attributes #[[ATTR0]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+crc,+fp-armv8,+lse,+neon,+ras,+rdm,+v8.1a,+v8.2a,+v8a" }
-// CHECK: attributes #[[ATTR1]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+crc,+fp-armv8,+fullfp16,+lse,+neon,+ras,+rdm,+sve,+v8.1a,+v8.2a,+v8a"
}
-// CHECK: attributes #[[ATTR2]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+crc,+fp-armv8,+fullfp16,+lse,+neon,+ras,+rdm,+sve,+sve2,+v8.1a,+v8.2a,+v8a"
}
-// CHECK: attributes #[[ATTR3]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+bf16,+bti,+ccidx,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+predres,+ras,+rcpc,+rdm,+sb,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a"
}
-// CHECK: attributes #[[ATTR4]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="cortex-a710"
"target-features"="+bf16,+bti,+ccidx,+complxnum,+crc,+dit,+dotprod,+ete,+flagm,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+mte,+neon,+pauth,+perfmon,+predres,+ras,+rcpc,+rdm,+sb,+ssbs,+sve,+sve-bitperm,+sve2,+trbe,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8a,+v9a"
}
+// CHECK: attributes #[[ATTR1]] = { noinline nounwind optnone
vscale_range(1,16) "no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+crc,+fp-armv8,+fullfp16,+lse,+neon,+ras,+rdm,+sve,+v8.1a,+v8.2a,+v8a"
}
+// CHECK: attributes #[[ATTR2]] = { noinline nounwind optnone
vscale_range(1,16) "no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+crc,+fp-armv8,+fullfp16,+lse,+neon,+ras,+rdm,+sve,+sve2,+v8.1a,+v8.2a,+v8a"
}
+// CHECK: attributes #[[ATTR3]] = { noinline nounwind optnone
vscale_range(1,16) "no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+bf16,+bti,+ccidx,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+predres,+ras,+rcpc,+rdm,+sb,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a"
}
+// CHECK: attributes #[[ATTR4]] = { noinline nounwind optnone
vscale_range(1,16) "no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="cortex-a710"
"target-features"="+bf16,+bti,+ccidx,+complxnum,+crc,+dit,+dotprod,+ete,+flagm,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+mte,+neon,+pauth,+perfmon,+predres,+ras,+rcpc,+rdm,+sb,+ssbs,+sve,+sve-bitperm,+sve2,+trbe,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8a,+v9a"
}
// CHECK: attributes #[[ATTR5]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"tune-cpu"="cortex-a710" }
// CHECK: attributes #[[ATTR6]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="generic" "target-features"="+ete,+fp-armv8,+neon,+trbe,+v8a" }
// CHECK: attributes #[[ATTR7]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"tune-cpu"="generic" }
// CHECK: attributes #[[ATTR8]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="neoverse-n1"
"target-features"="+aes,+crc,+dotprod,+fp-armv8,+fullfp16,+lse,+neon,+perfmon,+ras,+rcpc,+rdm,+sha2,+spe,+ssbs,+v8.1a,+v8.2a,+v8a"
"tune-cpu"="cortex-a710" }
-// CHECK: attributes #[[ATTR9]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+fp-armv8,+fullfp16,+sve" "tune-cpu"="cortex-a710" }
-// CHECK: attributes #[[ATTR10]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="neoverse-v1"
"target-features"="+aes,+bf16,+ccdp,+ccidx,+ccpp,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+rand,+ras,+rcpc,+rdm,+sha2,+sha3,+sm4,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8a"
}
+// CHECK: attributes #[[ATTR9]] = { noinline nounwind optnone
vscale_range(1,16) "no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+fp-armv8,+fullfp16,+sve" "tune-cpu"="cortex-a710" }
+// CHECK: attributes #[[ATTR10]] = { noinline nounwind optnone
vscale_range(1,16) "no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="neoverse-v1"
"target-features"="+aes,+bf16,+ccdp,+ccidx,+ccpp,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+rand,+ras,+rcpc,+rdm,+sha2,+sha3,+sm4,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8a"
}
// CHECK: attributes #[[ATTR11]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="neoverse-v1"
"target-features"="+aes,+bf16,+ccdp,+ccidx,+ccpp,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+rand,+ras,+rcpc,+rdm,+sha2,+sha3,+sm4,+spe,+ssbs,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8a,-sve"
}
-// CHECK: attributes #[[ATTR12]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+fp-armv8,+fullfp16,+sve" }
+// CHECK: attributes #[[ATTR12]] = { noinline nounwind optnone
vscale_range(1,16) "no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+fp-armv8,+fullfp16,+sve" }
// CHECK: attributes #[[ATTR13]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="+fp-armv8,+fullfp16" }
-// CHECK: attributes #[[ATTR14]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="neoverse-n1"
"target-features"="+aes,+bf16,+bti,+ccidx,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+predres,+ras,+rcpc,+rdm,+sb,+sha2,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a"
"tune-cpu"="cortex-a710" }
-// CHECK: attributes #[[ATTR15]] = { noinline nounwind optnone
"branch-target-enforcement" "guarded-control-stack" "no-trapping-math"="true"
"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
"stack-protector-buffer-size"="8" "target-cpu"="neoverse-n1"
"target-features"="+aes,+bf16,+bti,+ccidx,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+predres,+ras,+rcpc,+rdm,+sb,+sha2,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a"
"tune-cpu"="cortex-a710" }
+// CHECK: attributes #[[ATTR14]] = { noinline nounwind optnone
vscale_range(1,16) "no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="neoverse-n1"
"target-features"="+aes,+bf16,+bti,+ccidx,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+predres,+ras,+rcpc,+rdm,+sb,+sha2,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a"
"tune-cpu"="cortex-a710" }
+// CHECK: attributes #[[ATTR15]] = { noinline nounwind optnone
vscale_range(1,16) "branch-target-enforcement" "guarded-control-stack"
"no-trapping-math"="true" "sign-return-address"="non-leaf"
"sign-return-address-key"="a_key" "stack-protector-buffer-size"="8"
"target-cpu"="neoverse-n1"
"target-features"="+aes,+bf16,+bti,+ccidx,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+predres,+ras,+rcpc,+rdm,+sb,+sha2,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a"
"tune-cpu"="cortex-a710" }
// CHECK: attributes #[[ATTR16]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8" }
// CHECK: attributes #[[ATTR17]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-features"="-v9.3a" }
// CHECK: attributes #[[ATTR18]] = { noinline nounwind optnone
"no-trapping-math"="true" "stack-protector-buffer-size"="8"
"target-cpu"="apple-m4"
"target-features"="+aes,+bf16,+bti,+ccidx,+complxnum,+crc,+dit,+dotprod,+flagm,+fp-armv8,+fp16fml,+fpac,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+predres,+ras,+rcpc,+rdm,+sb,+sha2,+sha3,+sme,+sme-f64f64,+sme-i16i64,+sme2,+spe-eef,+ssbs,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8.7a,+v8a,+wfxt"
}
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