23 lines
792 B
LLVM
23 lines
792 B
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=fma -enable-unsafe-fp-math | FileCheck %s
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; If fast-math-flags are propagated correctly, the mul1 expression
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; should be recognized as a factor in the last fsub, so we should
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; see a mul and add, not a mul and fma:
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; a * b - (-a * b) ---> (a * b) + (a * b)
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define float @fmf_should_not_break_cse(float %a, float %b) {
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; CHECK-LABEL: fmf_should_not_break_cse:
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; CHECK: # %bb.0:
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; CHECK-NEXT: vmulss %xmm1, %xmm0, %xmm0
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; CHECK-NEXT: vaddss %xmm0, %xmm0, %xmm0
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; CHECK-NEXT: retq
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%mul1 = fmul fast float %a, %b
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%nega = fsub fast float 0.0, %a
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%mul2 = fmul fast float %nega, %b
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%abx2 = fsub fast float %mul1, %mul2
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ret float %abx2
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}
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