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[InstSimplify] use any-zero matcher for fcmp folds 

The m_APFloat matcher does not work with anything but strict
splat vector constants, so we could miss these folds and then
trigger an assertion in instcombine:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=13201

llvm-svn: 354406
This commit is contained in:
Sanjay Patel 2019-02-20 00:09:50 +00:00
parent 3ae6726234
commit 058bb83513
2 changed files with 29 additions and 34 deletions
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47
llvm/lib/Analysis/InstructionSimplify.cpp
View File

@ -3648,6 +3648,31 @@ static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
}
// Handle fcmp with constant RHS.
if (match(RHS, m_AnyZeroFP())) {
switch (Pred) {
case FCmpInst::FCMP_OGE:
if (FMF.noNaNs() && CannotBeOrderedLessThanZero(LHS, Q.TLI))
return getTrue(RetTy);
break;
case FCmpInst::FCMP_UGE:
if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
return getTrue(RetTy);
break;
case FCmpInst::FCMP_ULT:
if (FMF.noNaNs() && CannotBeOrderedLessThanZero(LHS, Q.TLI))
return getFalse(RetTy);
break;
case FCmpInst::FCMP_OLT:
if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
return getFalse(RetTy);
break;
default:
break;
}
}
// TODO: Use match with a specific FP value, so these work with vectors with
// undef lanes.
const APFloat *C;
if (match(RHS, m_APFloat(C))) {
// Check whether the constant is an infinity.
@ -3675,28 +3700,6 @@ static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
break;
}
}
}
if (C->isZero()) {
switch (Pred) {
case FCmpInst::FCMP_OGE:
if (FMF.noNaNs() && CannotBeOrderedLessThanZero(LHS, Q.TLI))
return getTrue(RetTy);
break;
case FCmpInst::FCMP_UGE:
if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
return getTrue(RetTy);
break;
case FCmpInst::FCMP_ULT:
if (FMF.noNaNs() && CannotBeOrderedLessThanZero(LHS, Q.TLI))
return getFalse(RetTy);
break;
case FCmpInst::FCMP_OLT:
if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
return getFalse(RetTy);
break;
default:
break;
}
} else if (C->isNegative()) {
assert(!C->isNaN() && "Unexpected NaN constant!");
// TODO: We can catch more cases by using a range check rather than

16
llvm/test/Transforms/InstSimplify/floating-point-compare.ll
View File

@ -399,9 +399,7 @@ define <2 x i1> @fabs_is_not_negative_poszero(<2 x float> %V) {
define <2 x i1> @fabs_is_not_negative_anyzero(<2 x float> %V) {
; CHECK-LABEL: @fabs_is_not_negative_anyzero(
; CHECK-NEXT: [[ABS:%.*]] = call <2 x float> @llvm.fabs.v2f32(<2 x float> [[V:%.*]])
; CHECK-NEXT: [[CMP:%.*]] = fcmp olt <2 x float> [[ABS]], <float 0.000000e+00, float -0.000000e+00>
; CHECK-NEXT: ret <2 x i1> [[CMP]]
; CHECK-NEXT: ret <2 x i1> zeroinitializer
;
%abs = call <2 x float> @llvm.fabs.v2f32(<2 x float> %V)
%cmp = fcmp olt <2 x float> %abs, <float 0.0, float -0.0>
@ -410,9 +408,7 @@ define <2 x i1> @fabs_is_not_negative_anyzero(<2 x float> %V) {
define <3 x i1> @fabs_is_not_negative_negzero_undef(<3 x float> %V) {
; CHECK-LABEL: @fabs_is_not_negative_negzero_undef(
; CHECK-NEXT: [[ABS:%.*]] = call <3 x float> @llvm.fabs.v3f32(<3 x float> [[V:%.*]])
; CHECK-NEXT: [[CMP:%.*]] = fcmp olt <3 x float> [[ABS]], <float -0.000000e+00, float -0.000000e+00, float undef>
; CHECK-NEXT: ret <3 x i1> [[CMP]]
; CHECK-NEXT: ret <3 x i1> zeroinitializer
;
%abs = call <3 x float> @llvm.fabs.v3f32(<3 x float> %V)
%cmp = fcmp olt <3 x float> %abs, <float -0.0, float -0.0, float undef>
@ -421,9 +417,7 @@ define <3 x i1> @fabs_is_not_negative_negzero_undef(<3 x float> %V) {
define <3 x i1> @fabs_is_not_negative_poszero_undef(<3 x float> %V) {
; CHECK-LABEL: @fabs_is_not_negative_poszero_undef(
; CHECK-NEXT: [[ABS:%.*]] = call <3 x float> @llvm.fabs.v3f32(<3 x float> [[V:%.*]])
; CHECK-NEXT: [[CMP:%.*]] = fcmp olt <3 x float> [[ABS]], <float 0.000000e+00, float 0.000000e+00, float undef>
; CHECK-NEXT: ret <3 x i1> [[CMP]]
; CHECK-NEXT: ret <3 x i1> zeroinitializer
;
%abs = call <3 x float> @llvm.fabs.v3f32(<3 x float> %V)
%cmp = fcmp olt <3 x float> %abs, <float 0.0, float 0.0, float undef>
@ -432,9 +426,7 @@ define <3 x i1> @fabs_is_not_negative_poszero_undef(<3 x float> %V) {
define <3 x i1> @fabs_is_not_negative_anyzero_undef(<3 x float> %V) {
; CHECK-LABEL: @fabs_is_not_negative_anyzero_undef(
; CHECK-NEXT: [[ABS:%.*]] = call <3 x float> @llvm.fabs.v3f32(<3 x float> [[V:%.*]])
; CHECK-NEXT: [[CMP:%.*]] = fcmp olt <3 x float> [[ABS]], <float 0.000000e+00, float -0.000000e+00, float undef>
; CHECK-NEXT: ret <3 x i1> [[CMP]]
; CHECK-NEXT: ret <3 x i1> zeroinitializer
;
%abs = call <3 x float> @llvm.fabs.v3f32(<3 x float> %V)
%cmp = fcmp olt <3 x float> %abs, <float 0.0, float -0.0, float undef>