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[InstCombine] propagate FMF for fcmp+fabs folds 

By morphing the instruction rather than deleting and creating a new one,
we retain fast-math-flags and potentially other metadata (profile info?).

llvm-svn: 346331
This commit is contained in:
Sanjay Patel 2018-11-07 16:15:01 +00:00
parent c544838f87
commit 57a08b3343
2 changed files with 25 additions and 19 deletions
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20
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
View File

@ -5291,6 +5291,12 @@ static Instruction *foldFabsWithFcmpZero(FCmpInst &I) {
!match(I.getOperand(1), m_PosZeroFP()))
return nullptr;
auto replacePredAndOp0 = [](FCmpInst *I, FCmpInst::Predicate P, Value *X) {
I->setPredicate(P);
I->setOperand(0, X);
return I;
};
switch (I.getPredicate()) {
case FCmpInst::FCMP_UGE:
case FCmpInst::FCMP_OLT:
@ -5300,29 +5306,29 @@ static Instruction *foldFabsWithFcmpZero(FCmpInst &I) {
case FCmpInst::FCMP_OGT:
// fabs(X) > 0.0 --> X != 0.0
return new FCmpInst(FCmpInst::FCMP_ONE, X, I.getOperand(1));
return replacePredAndOp0(&I, FCmpInst::FCMP_ONE, X);
case FCmpInst::FCMP_UGT:
// fabs(X) u> 0.0 --> X u!= 0.0
return new FCmpInst(FCmpInst::FCMP_UNE, X, I.getOperand(1));
return replacePredAndOp0(&I, FCmpInst::FCMP_UNE, X);
case FCmpInst::FCMP_OLE:
// fabs(X) <= 0.0 --> X == 0.0
return new FCmpInst(FCmpInst::FCMP_OEQ, X, I.getOperand(1));
return replacePredAndOp0(&I, FCmpInst::FCMP_OEQ, X);
case FCmpInst::FCMP_ULE:
// fabs(X) u<= 0.0 --> X u== 0.0
return new FCmpInst(FCmpInst::FCMP_UEQ, X, I.getOperand(1));
return replacePredAndOp0(&I, FCmpInst::FCMP_UEQ, X);
case FCmpInst::FCMP_OGE:
// fabs(X) >= 0.0 --> !isnan(X)
assert(!I.hasNoNaNs() && "fcmp should have simplified");
return new FCmpInst(FCmpInst::FCMP_ORD, X, I.getOperand(1));
return replacePredAndOp0(&I, FCmpInst::FCMP_ORD, X);
case FCmpInst::FCMP_ULT:
// fabs(X) u< 0.0 --> isnan(X)
assert(!I.hasNoNaNs() && "fcmp should have simplified");
return new FCmpInst(FCmpInst::FCMP_UNO, X, I.getOperand(1));
return replacePredAndOp0(&I, FCmpInst::FCMP_UNO, X);
case FCmpInst::FCMP_OEQ:
case FCmpInst::FCMP_UEQ:
@ -5335,7 +5341,7 @@ static Instruction *foldFabsWithFcmpZero(FCmpInst &I) {
// fabs(X) != 0.0 --> X != 0.0
// isnan(fabs(X)) --> isnan(X)
// !isnan(fabs(X) --> !isnan(X)
return new FCmpInst(I.getPredicate(), X, I.getOperand(1));
return replacePredAndOp0(&I, I.getPredicate(), X);
default:
return nullptr;

24
llvm/test/Transforms/InstCombine/fcmp.ll
View File

@ -189,7 +189,7 @@ define i1 @fabs_olt(half %a) {
define <2 x i1> @fabs_ole(<2 x float> %a) {
; CHECK-LABEL: @fabs_ole(
; CHECK-NEXT: [[CMP:%.*]] = fcmp oeq <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: [[CMP:%.*]] = fcmp ninf oeq <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%call = call <2 x float> @llvm.fabs.v2f32(<2 x float> %a)
@ -199,7 +199,7 @@ define <2 x i1> @fabs_ole(<2 x float> %a) {
define <2 x i1> @fabs_ule(<2 x float> %a) {
; CHECK-LABEL: @fabs_ule(
; CHECK-NEXT: [[CMP:%.*]] = fcmp ueq <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: [[CMP:%.*]] = fcmp ninf arcp ueq <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%call = call <2 x float> @llvm.fabs.v2f32(<2 x float> %a)
@ -209,7 +209,7 @@ define <2 x i1> @fabs_ule(<2 x float> %a) {
define i1 @fabs_ogt(double %a) {
; CHECK-LABEL: @fabs_ogt(
; CHECK-NEXT: [[CMP:%.*]] = fcmp one double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: [[CMP:%.*]] = fcmp reassoc one double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: ret i1 [[CMP]]
;
%call = call double @llvm.fabs.f64(double %a)
@ -219,7 +219,7 @@ define i1 @fabs_ogt(double %a) {
define i1 @fabs_ugt(double %a) {
; CHECK-LABEL: @fabs_ugt(
; CHECK-NEXT: [[CMP:%.*]] = fcmp une double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: [[CMP:%.*]] = fcmp reassoc ninf une double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: ret i1 [[CMP]]
;
%call = call double @llvm.fabs.f64(double %a)
@ -229,7 +229,7 @@ define i1 @fabs_ugt(double %a) {
define i1 @fabs_oge(double %a) {
; CHECK-LABEL: @fabs_oge(
; CHECK-NEXT: [[CMP:%.*]] = fcmp ord double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: [[CMP:%.*]] = fcmp afn ord double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: ret i1 [[CMP]]
;
%call = call double @llvm.fabs.f64(double %a)
@ -239,7 +239,7 @@ define i1 @fabs_oge(double %a) {
define i1 @fabs_ult(double %a) {
; CHECK-LABEL: @fabs_ult(
; CHECK-NEXT: [[CMP:%.*]] = fcmp uno double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: [[CMP:%.*]] = fcmp reassoc arcp uno double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: ret i1 [[CMP]]
;
%call = call double @llvm.fabs.f64(double %a)
@ -258,7 +258,7 @@ define <2 x i1> @fabs_ult_nnan(<2 x float> %a) {
define i1 @fabs_une(half %a) {
; CHECK-LABEL: @fabs_une(
; CHECK-NEXT: [[CMP:%.*]] = fcmp une half [[A:%.*]], 0xH0000
; CHECK-NEXT: [[CMP:%.*]] = fcmp ninf une half [[A:%.*]], 0xH0000
; CHECK-NEXT: ret i1 [[CMP]]
;
%call = call half @llvm.fabs.f16(half %a)
@ -268,7 +268,7 @@ define i1 @fabs_une(half %a) {
define i1 @fabs_oeq(double %a) {
; CHECK-LABEL: @fabs_oeq(
; CHECK-NEXT: [[CMP:%.*]] = fcmp oeq double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: [[CMP:%.*]] = fcmp reassoc ninf oeq double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: ret i1 [[CMP]]
;
%call = call double @llvm.fabs.f64(double %a)
@ -278,7 +278,7 @@ define i1 @fabs_oeq(double %a) {
define i1 @fabs_one(double %a) {
; CHECK-LABEL: @fabs_one(
; CHECK-NEXT: [[CMP:%.*]] = fcmp one double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: [[CMP:%.*]] = fcmp fast one double [[A:%.*]], 0.000000e+00
; CHECK-NEXT: ret i1 [[CMP]]
;
%call = call double @llvm.fabs.f64(double %a)
@ -288,7 +288,7 @@ define i1 @fabs_one(double %a) {
define <2 x i1> @fabs_ueq(<2 x float> %a) {
; CHECK-LABEL: @fabs_ueq(
; CHECK-NEXT: [[CMP:%.*]] = fcmp ueq <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: [[CMP:%.*]] = fcmp arcp ueq <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%call = call <2 x float> @llvm.fabs.v2f32(<2 x float> %a)
@ -298,7 +298,7 @@ define <2 x i1> @fabs_ueq(<2 x float> %a) {
define <2 x i1> @fabs_ord(<2 x float> %a) {
; CHECK-LABEL: @fabs_ord(
; CHECK-NEXT: [[CMP:%.*]] = fcmp ord <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: [[CMP:%.*]] = fcmp arcp ord <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%call = call <2 x float> @llvm.fabs.v2f32(<2 x float> %a)
@ -308,7 +308,7 @@ define <2 x i1> @fabs_ord(<2 x float> %a) {
define <2 x i1> @fabs_uno(<2 x float> %a) {
; CHECK-LABEL: @fabs_uno(
; CHECK-NEXT: [[CMP:%.*]] = fcmp uno <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: [[CMP:%.*]] = fcmp arcp uno <2 x float> [[A:%.*]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%call = call <2 x float> @llvm.fabs.v2f32(<2 x float> %a)