maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[FPEnv][InstSimplify] Teach CannotBeNegativeZero() about constrained intrinsics. 

Currently some optimizations are disabled because llvm::CannotBeNegativeZero()
does not know how to deal with the constrained intrinsics. This patch fixes
that by extending the existing implementation.

Differential Revision: https://reviews.llvm.org/D121483
This commit is contained in:
Kevin P. Neal 2022-03-18 10:22:15 -04:00
parent c59c2b6bd1
commit bd050a34fe
3 changed files with 19 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
llvm/lib/Analysis/ValueTracking.cpp
View File

@ -3397,9 +3397,6 @@ Intrinsic::ID llvm::getIntrinsicForCallSite(const CallBase &CB,
/// NOTE: Do not check 'nsz' here because that fast-math-flag does not guarantee
/// that a value is not -0.0. It only guarantees that -0.0 may be treated
/// the same as +0.0 in floating-point ops.
///
/// NOTE: this function will need to be revisited when we support non-default
/// rounding modes!
bool llvm::CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI,
unsigned Depth) {
if (auto *CFP = dyn_cast<ConstantFP>(V))
@ -3429,9 +3426,21 @@ bool llvm::CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI,
case Intrinsic::sqrt:
case Intrinsic::canonicalize:
return CannotBeNegativeZero(Call->getArgOperand(0), TLI, Depth + 1);
case Intrinsic::experimental_constrained_sqrt: {
// NOTE: This rounding mode restriction may be too strict.
const auto *CI = cast<ConstrainedFPIntrinsic>(Call);
if (CI->getRoundingMode() == RoundingMode::NearestTiesToEven)
return CannotBeNegativeZero(Call->getArgOperand(0), TLI, Depth + 1);
else
return false;
}
// fabs(x) != -0.0
case Intrinsic::fabs:
return true;
// sitofp and uitofp turn into +0.0 for zero.
case Intrinsic::experimental_constrained_sitofp:
case Intrinsic::experimental_constrained_uitofp:
return true;
}
}

4
llvm/test/Transforms/InstSimplify/strictfp-fsub.ll
View File

@ -216,12 +216,10 @@ define float @fold_fsub_fabs_nnan_x_n0_ebstrict(float %a) #0 {
ret float %sub
}
; TODO: This can't fire currently due to missing constrained support:
define float @fold_fsub_sitofp_x_n0_defaultenv(i32 %a) #0 {
; CHECK-LABEL: @fold_fsub_sitofp_x_n0_defaultenv(
; CHECK-NEXT: [[FPA:%.*]] = call float @llvm.experimental.constrained.sitofp.f32.i32(i32 [[A:%.*]], metadata !"round.tonearest", metadata !"fpexcept.ignore") #[[ATTR0]]
; CHECK-NEXT: [[SUB:%.*]] = call float @llvm.experimental.constrained.fsub.f32(float [[FPA]], float -0.000000e+00, metadata !"round.tonearest", metadata !"fpexcept.ignore") #[[ATTR0]]
; CHECK-NEXT: ret float [[SUB]]
; CHECK-NEXT: ret float [[FPA]]
;
%fpa = call float @llvm.experimental.constrained.sitofp.f32.i32(i32 %a, metadata !"round.tonearest", metadata !"fpexcept.ignore") #0
%sub = call float @llvm.experimental.constrained.fsub.f32(float %fpa, float -0.0, metadata !"round.tonearest", metadata !"fpexcept.ignore") #0

16
llvm/test/Transforms/InstSimplify/strictfp-sqrt-nonneg.ll
View File

@ -9,8 +9,7 @@ define float @nonneg_u_defaultenv(i32 %a) #0 {
; CHECK-LABEL: @nonneg_u_defaultenv(
; CHECK-NEXT: [[FPA:%.*]] = call float @llvm.experimental.constrained.uitofp.f32.i32(i32 [[A:%.*]], metadata !"round.tonearest", metadata !"fpexcept.ignore") #[[ATTR0:[0-9]+]]
; CHECK-NEXT: [[SQRA:%.*]] = call float @llvm.experimental.constrained.sqrt.f32(float [[FPA]], metadata !"round.tonearest", metadata !"fpexcept.ignore") #[[ATTR0]]
; CHECK-NEXT: [[SUB:%.*]] = call float @llvm.experimental.constrained.fsub.f32(float [[SQRA]], float -0.000000e+00, metadata !"round.tonearest", metadata !"fpexcept.ignore") #[[ATTR0]]
; CHECK-NEXT: ret float [[SUB]]
; CHECK-NEXT: ret float [[SQRA]]
;
%fpa = call float @llvm.experimental.constrained.uitofp.f32.i32(i32 %a, metadata !"round.tonearest", metadata !"fpexcept.ignore") #0
%sqra = call float @llvm.experimental.constrained.sqrt.f32(float %fpa, metadata !"round.tonearest", metadata !"fpexcept.ignore") #0
@ -22,8 +21,7 @@ define float @nonneg_s_defaultenv(i32 %a) #0 {
; CHECK-LABEL: @nonneg_s_defaultenv(
; CHECK-NEXT: [[FPA:%.*]] = call float @llvm.experimental.constrained.sitofp.f32.i32(i32 [[A:%.*]], metadata !"round.tonearest", metadata !"fpexcept.ignore") #[[ATTR0]]
; CHECK-NEXT: [[SQRA:%.*]] = call float @llvm.experimental.constrained.sqrt.f32(float [[FPA]], metadata !"round.tonearest", metadata !"fpexcept.ignore") #[[ATTR0]]
; CHECK-NEXT: [[SUB:%.*]] = call float @llvm.experimental.constrained.fsub.f32(float [[SQRA]], float -0.000000e+00, metadata !"round.tonearest", metadata !"fpexcept.ignore") #[[ATTR0]]
; CHECK-NEXT: ret float [[SUB]]
; CHECK-NEXT: ret float [[SQRA]]
;
%fpa = call float @llvm.experimental.constrained.sitofp.f32.i32(i32 %a, metadata !"round.tonearest", metadata !"fpexcept.ignore") #0
%sqra = call float @llvm.experimental.constrained.sqrt.f32(float %fpa, metadata !"round.tonearest", metadata !"fpexcept.ignore") #0
@ -35,8 +33,7 @@ define float @nonneg_u_maytrap(i32 %a) #0 {
; CHECK-LABEL: @nonneg_u_maytrap(
; CHECK-NEXT: [[FPA:%.*]] = call float @llvm.experimental.constrained.uitofp.f32.i32(i32 [[A:%.*]], metadata !"round.tonearest", metadata !"fpexcept.maytrap") #[[ATTR0]]
; CHECK-NEXT: [[SQRA:%.*]] = call float @llvm.experimental.constrained.sqrt.f32(float [[FPA]], metadata !"round.tonearest", metadata !"fpexcept.maytrap") #[[ATTR0]]
; CHECK-NEXT: [[SUB:%.*]] = call nnan float @llvm.experimental.constrained.fsub.f32(float [[SQRA]], float -0.000000e+00, metadata !"round.tonearest", metadata !"fpexcept.maytrap") #[[ATTR0]]
; CHECK-NEXT: ret float [[SUB]]
; CHECK-NEXT: ret float [[SQRA]]
;
%fpa = call float @llvm.experimental.constrained.uitofp.f32.i32(i32 %a, metadata !"round.tonearest", metadata !"fpexcept.maytrap") #0
%sqra = call float @llvm.experimental.constrained.sqrt.f32(float %fpa, metadata !"round.tonearest", metadata !"fpexcept.maytrap") #0
@ -48,8 +45,7 @@ define float @nonneg_s_maytrap(i32 %a) #0 {
; CHECK-LABEL: @nonneg_s_maytrap(
; CHECK-NEXT: [[FPA:%.*]] = call float @llvm.experimental.constrained.sitofp.f32.i32(i32 [[A:%.*]], metadata !"round.tonearest", metadata !"fpexcept.maytrap") #[[ATTR0]]
; CHECK-NEXT: [[SQRA:%.*]] = call float @llvm.experimental.constrained.sqrt.f32(float [[FPA]], metadata !"round.tonearest", metadata !"fpexcept.maytrap") #[[ATTR0]]
; CHECK-NEXT: [[SUB:%.*]] = call nnan float @llvm.experimental.constrained.fsub.f32(float [[SQRA]], float -0.000000e+00, metadata !"round.tonearest", metadata !"fpexcept.maytrap") #[[ATTR0]]
; CHECK-NEXT: ret float [[SUB]]
; CHECK-NEXT: ret float [[SQRA]]
;
%fpa = call float @llvm.experimental.constrained.sitofp.f32.i32(i32 %a, metadata !"round.tonearest", metadata !"fpexcept.maytrap") #0
%sqra = call float @llvm.experimental.constrained.sqrt.f32(float %fpa, metadata !"round.tonearest", metadata !"fpexcept.maytrap") #0
@ -63,7 +59,7 @@ define float @nonneg_u_ebstrict(i32 %a) #0 {
; CHECK-NEXT: [[FPA:%.*]] = call float @llvm.experimental.constrained.uitofp.f32.i32(i32 [[A:%.*]], metadata !"round.tonearest", metadata !"fpexcept.strict") #[[ATTR0]]
; CHECK-NEXT: [[SQRA:%.*]] = call float @llvm.experimental.constrained.sqrt.f32(float [[FPA]], metadata !"round.tonearest", metadata !"fpexcept.strict") #[[ATTR0]]
; CHECK-NEXT: [[SUB:%.*]] = call nnan float @llvm.experimental.constrained.fsub.f32(float [[SQRA]], float -0.000000e+00, metadata !"round.tonearest", metadata !"fpexcept.strict") #[[ATTR0]]
; CHECK-NEXT: ret float [[SUB]]
; CHECK-NEXT: ret float [[SQRA]]
;
%fpa = call float @llvm.experimental.constrained.uitofp.f32.i32(i32 %a, metadata !"round.tonearest", metadata !"fpexcept.strict") #0
%sqra = call float @llvm.experimental.constrained.sqrt.f32(float %fpa, metadata !"round.tonearest", metadata !"fpexcept.strict") #0
@ -77,7 +73,7 @@ define float @nonneg_s_ebstrict(i32 %a) #0 {
; CHECK-NEXT: [[FPA:%.*]] = call float @llvm.experimental.constrained.sitofp.f32.i32(i32 [[A:%.*]], metadata !"round.tonearest", metadata !"fpexcept.strict") #[[ATTR0]]
; CHECK-NEXT: [[SQRA:%.*]] = call float @llvm.experimental.constrained.sqrt.f32(float [[FPA]], metadata !"round.tonearest", metadata !"fpexcept.strict") #[[ATTR0]]
; CHECK-NEXT: [[SUB:%.*]] = call nnan float @llvm.experimental.constrained.fsub.f32(float [[SQRA]], float -0.000000e+00, metadata !"round.tonearest", metadata !"fpexcept.strict") #[[ATTR0]]
; CHECK-NEXT: ret float [[SUB]]
; CHECK-NEXT: ret float [[SQRA]]
;
%fpa = call float @llvm.experimental.constrained.sitofp.f32.i32(i32 %a, metadata !"round.tonearest", metadata !"fpexcept.strict") #0
%sqra = call float @llvm.experimental.constrained.sqrt.f32(float %fpa, metadata !"round.tonearest", metadata !"fpexcept.strict") #0