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[InstCombine] propagate fast-math-flags when folding fcmp+fneg, part 2 

llvm-svn: 346238
This commit is contained in:
Sanjay Patel 2018-11-06 15:58:57 +00:00
parent b3fbba6d15
commit 2fd5b0ebfb
2 changed files with 5 additions and 4 deletions
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5
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
View File

@ -5467,9 +5467,10 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
Value *X, *Y;
if (match(Op0, m_FNeg(m_Value(X)))) {
if (match(Op1, m_FNeg(m_Value(Y)))) {
// FIXME: Drops FMF.
// fcmp pred (fneg X), (fneg Y) -> fcmp swap(pred) X, Y
return new FCmpInst(I.getSwappedPredicate(), X, Y);
Instruction *NewFCmp = new FCmpInst(I.getSwappedPredicate(), X, Y);
NewFCmp->copyFastMathFlags(&I);
return NewFCmp;
}
Constant *C;

4
llvm/test/Transforms/InstCombine/fcmp.ll
View File

@ -104,7 +104,7 @@ define <2 x i1> @fcmp_fneg_fmf_vec(<2 x float> %x) {
define i1 @fneg_fneg_swap_pred(float %x, float %y) {
; CHECK-LABEL: @fneg_fneg_swap_pred(
; CHECK-NEXT: [[CMP:%.*]] = fcmp ogt float [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[CMP:%.*]] = fcmp nnan ogt float [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: ret i1 [[CMP]]
;
%neg1 = fsub float -0.0, %x
@ -115,7 +115,7 @@ define i1 @fneg_fneg_swap_pred(float %x, float %y) {
define <2 x i1> @fneg_fneg_swap_pred_vec(<2 x float> %x, <2 x float> %y) {
; CHECK-LABEL: @fneg_fneg_swap_pred_vec(
; CHECK-NEXT: [[CMP:%.*]] = fcmp ogt <2 x float> [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[CMP:%.*]] = fcmp ninf ogt <2 x float> [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%neg1 = fsub <2 x float> <float -0.0, float -0.0>, %x