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Reduce the number of attributes attached to each function 

This takes advantage of the implicit default behavior to reduce the number of
attributes, which in turns reduces compilation time. I've observed -3% in
instruction count when compiling sqlite3 amalgamation with -O0

Differential Revision: https://reviews.llvm.org/D96400
This commit is contained in:
serge-sans-paille 2021-02-10 09:42:50 +01:00
parent 397336dcab
commit 3c8bf29f14
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GPG Key ID: 7B24DA8C9551659F
4 changed files with 35 additions and 36 deletions
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29
clang/lib/CodeGen/CGCall.cpp
View File

@ -1773,8 +1773,8 @@ void CodeGenModule::getDefaultFunctionAttributes(StringRef Name,
}
FuncAttrs.addAttribute("frame-pointer", FpKind);
FuncAttrs.addAttribute("less-precise-fpmad",
llvm::toStringRef(CodeGenOpts.LessPreciseFPMAD));
if (CodeGenOpts.LessPreciseFPMAD)
FuncAttrs.addAttribute("less-precise-fpmad", "true");
if (CodeGenOpts.NullPointerIsValid)
FuncAttrs.addAttribute(llvm::Attribute::NullPointerIsValid);
@ -1788,9 +1788,8 @@ void CodeGenModule::getDefaultFunctionAttributes(StringRef Name,
CodeGenOpts.FP32DenormalMode.str());
}
FuncAttrs.addAttribute("no-trapping-math",
llvm::toStringRef(LangOpts.getFPExceptionMode() ==
LangOptions::FPE_Ignore));
if (LangOpts.getFPExceptionMode() == LangOptions::FPE_Ignore)
FuncAttrs.addAttribute("no-trapping-math", "true");
// Strict (compliant) code is the default, so only add this attribute to
// indicate that we are trying to workaround a problem case.
@ -1799,18 +1798,18 @@ void CodeGenModule::getDefaultFunctionAttributes(StringRef Name,
// TODO: Are these all needed?
// unsafe/inf/nan/nsz are handled by instruction-level FastMathFlags.
FuncAttrs.addAttribute("no-infs-fp-math",
llvm::toStringRef(LangOpts.NoHonorInfs));
FuncAttrs.addAttribute("no-nans-fp-math",
llvm::toStringRef(LangOpts.NoHonorNaNs));
FuncAttrs.addAttribute("unsafe-fp-math",
llvm::toStringRef(LangOpts.UnsafeFPMath));
FuncAttrs.addAttribute("use-soft-float",
llvm::toStringRef(CodeGenOpts.SoftFloat));
if (LangOpts.NoHonorInfs)
FuncAttrs.addAttribute("no-infs-fp-math", "true");
if (LangOpts.NoHonorNaNs)
FuncAttrs.addAttribute("no-nans-fp-math", "true");
if (LangOpts.UnsafeFPMath)
FuncAttrs.addAttribute("unsafe-fp-math", "true");
if (CodeGenOpts.SoftFloat)
FuncAttrs.addAttribute("use-soft-float", "true");
FuncAttrs.addAttribute("stack-protector-buffer-size",
llvm::utostr(CodeGenOpts.SSPBufferSize));
FuncAttrs.addAttribute("no-signed-zeros-fp-math",
llvm::toStringRef(LangOpts.NoSignedZero));
if (LangOpts.NoSignedZero)
FuncAttrs.addAttribute("no-signed-zeros-fp-math", "true");
// TODO: Reciprocal estimate codegen options should apply to instructions?
const std::vector<std::string> &Recips = CodeGenOpts.Reciprocals;

4
clang/test/CodeGen/attr-target-x87-softfp.c
View File

@ -8,9 +8,9 @@ int __attribute__((target("no-x87"))) bar(int a) { return 4; }
// CHECK: bar{{.*}} #1
// CHECK: #0 = {{.*}}"target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87"
// HARD: "use-soft-float"="false"
// HARD-NOT: "use-soft-float"
// SOFT: "use-soft-float"="true"
// CHECK: #1 = {{.*}}"target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,-x87"
// HARD: "use-soft-float"="false"
// HARD-NOT: "use-soft-float"
// SOFT: "use-soft-float"="true"

2
clang/test/CodeGenOpenCL/no-signed-zeros.cl
View File

@ -6,5 +6,5 @@ float signedzeros(float a) {
}
// CHECK: attributes
// NORMAL: "no-signed-zeros-fp-math"="false"
// NORMAL-NOT: "no-signed-zeros-fp-math"
// NO-SIGNED-ZEROS: "no-signed-zeros-fp-math"="true"

36
clang/test/CodeGenOpenCL/relaxed-fpmath.cl
View File

@ -29,11 +29,11 @@ float spscalardiv(float a, float b) {
}
// CHECK: attributes
// NORMAL: "less-precise-fpmad"="false"
// NORMAL: "no-infs-fp-math"="false"
// NORMAL: "no-nans-fp-math"="false"
// NORMAL: "no-signed-zeros-fp-math"="false"
// NORMAL: "unsafe-fp-math"="false"
// NORMAL-NOT: "less-precise-fpmad"
// NORMAL-NOT: "no-infs-fp-math"
// NORMAL-NOT: "no-nans-fp-math"
// NORMAL-NOT: "no-signed-zeros-fp-math"
// NORMAL-NOT: "unsafe-fp-math"
// FAST: "less-precise-fpmad"="true"
// FAST: "no-infs-fp-math"="true"
@ -41,29 +41,29 @@ float spscalardiv(float a, float b) {
// FAST: "no-signed-zeros-fp-math"="true"
// FAST: "unsafe-fp-math"="true"
// FINITE: "less-precise-fpmad"="false"
// FINITE-NOT: "less-precise-fpmad"
// FINITE: "no-infs-fp-math"="true"
// FINITE: "no-nans-fp-math"="true"
// FINITE: "no-signed-zeros-fp-math"="false"
// FINITE: "unsafe-fp-math"="false"
// FINITE-NOT: "no-signed-zeros-fp-math"
// FINITE-NOT: "unsafe-fp-math"
// UNSAFE: "less-precise-fpmad"="true"
// UNSAFE: "no-infs-fp-math"="false"
// UNSAFE: "no-nans-fp-math"="false"
// UNSAFE-NOT: "no-infs-fp-math"
// UNSAFE-NOT: "no-nans-fp-math"
// UNSAFE: "no-signed-zeros-fp-math"="true"
// UNSAFE: "unsafe-fp-math"="true"
// MAD: "less-precise-fpmad"="true"
// MAD: "no-infs-fp-math"="false"
// MAD: "no-nans-fp-math"="false"
// MAD: "no-signed-zeros-fp-math"="false"
// MAD: "unsafe-fp-math"="false"
// MAD-NOT: "no-infs-fp-math"
// MAD-NOT: "no-nans-fp-math"
// MAD-NOT: "no-signed-zeros-fp-math"
// MAD-NOT: "unsafe-fp-math"
// NOSIGNED: "less-precise-fpmad"="false"
// NOSIGNED: "no-infs-fp-math"="false"
// NOSIGNED: "no-nans-fp-math"="false"
// NOSIGNED-NOT: "less-precise-fpmad"
// NOSIGNED-NOT: "no-infs-fp-math"
// NOSIGNED-NOT: "no-nans-fp-math"
// NOSIGNED: "no-signed-zeros-fp-math"="true"
// NOSIGNED: "unsafe-fp-math"="false"
// NOSIGNED-NOT: "unsafe-fp-math"
#else
// Undefine this to avoid putting it in the PCH.