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X86 doesn't have fneg, so check for xor. Differential Revision: http://reviews.llvm.org/D4812 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214992 91177308-0d34-0410-b5e6-96231b3b80d8
24 lines
847 B
LLVM
24 lines
847 B
LLVM
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mcpu=corei7 | FileCheck %s
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; FNEG is defined as subtraction from -0.0.
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; This test verifies that we use an xor with a constant to flip the sign bits; no subtraction needed.
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define <4 x float> @t1(<4 x float> %Q) {
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; CHECK-LABEL: t1:
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; CHECK: xorps {{.*}}LCPI0_0{{.*}}, %xmm0
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; CHECK-NEXT: retq
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%tmp = fsub <4 x float> < float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00 >, %Q
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ret <4 x float> %tmp
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}
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; This test verifies that we generate an FP subtraction because "0.0 - x" is not an fneg.
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define <4 x float> @t2(<4 x float> %Q) {
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; CHECK-LABEL: t2:
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; CHECK: xorps %[[X:xmm[0-9]+]], %[[X]]
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; CHECK-NEXT: subps %xmm0, %[[X]]
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; CHECK-NEXT: movaps %[[X]], %xmm0
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; CHECK-NEXT: retq
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%tmp = fsub <4 x float> zeroinitializer, %Q
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ret <4 x float> %tmp
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}
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