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InstCombine: fold fcmp (fneg x), (fneg y) -> fcmp x, y 

llvm-svn: 128627
This commit is contained in:
Benjamin Kramer 2011-03-31 10:12:22 +00:00
parent a8c5d0872d
commit d159d94644
2 changed files with 14 additions and 0 deletions
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5
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
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@ -2855,6 +2855,11 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
}
}
// fcmp (fneg x), (fneg y) -> fcmp x, y
Value *X, *Y;
if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_FNeg(m_Value(Y))))
return new FCmpInst(I.getPredicate(), X, Y);
// fcmp (fpext x), (fpext y) -> fcmp x, y
if (FPExtInst *LHSExt = dyn_cast<FPExtInst>(Op0))
if (FPExtInst *RHSExt = dyn_cast<FPExtInst>(Op1))

9
llvm/test/Transforms/InstCombine/fcmp.ll
View File

@ -40,3 +40,12 @@ define i1 @test5(float %a) nounwind {
; CHECK: @test5
; CHECK-NEXT: fcmp olt float %a, -1.0
}
define i1 @test6(float %x, float %y) nounwind {
%neg1 = fsub float -0.000000e+00, %x
%neg2 = fsub float -0.000000e+00, %y
%cmp = fcmp ogt float %neg1, %neg2
ret i1 %cmp
; CHECK: @test6
; CHECK-NEXT: fcmp ogt float %x, %y
}