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3ece478445
This accounts for the missing IR fold noted in D50195. We don't need any fast-math to enable the negation transform. FP negation can always be folded into an fmul/fdiv constant to eliminate the fneg. I've limited this to one-use to ensure that we are eliminating an instruction rather than replacing fneg by a potentially expensive fdiv or fmul. Differential Revision: https://reviews.llvm.org/D50417 llvm-svn: 339248
159 lines
5.2 KiB
LLVM
159 lines
5.2 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -instcombine -S | FileCheck %s
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declare void @use(float)
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; -(X * C) --> X * (-C)
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define float @fmul_fneg(float %x) {
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; CHECK-LABEL: @fmul_fneg(
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; CHECK-NEXT: [[R:%.*]] = fmul float [[X:%.*]], -4.200000e+01
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; CHECK-NEXT: ret float [[R]]
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;
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%m = fmul float %x, 42.0
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%r = fsub float -0.0, %m
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ret float %r
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}
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; Fast math is not required, but it should be propagated.
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define float @fmul_fneg_fmf(float %x) {
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; CHECK-LABEL: @fmul_fneg_fmf(
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; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -4.200000e+01
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; CHECK-NEXT: ret float [[R]]
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;
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%m = fmul float %x, 42.0
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%r = fsub reassoc nsz float -0.0, %m
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ret float %r
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}
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; Extra use prevents the fold. We don't want to replace the fneg with an fmul.
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define float @fmul_fneg_extra_use(float %x) {
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; CHECK-LABEL: @fmul_fneg_extra_use(
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; CHECK-NEXT: [[M:%.*]] = fmul float [[X:%.*]], 4.200000e+01
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; CHECK-NEXT: [[R:%.*]] = fsub float -0.000000e+00, [[M]]
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; CHECK-NEXT: call void @use(float [[M]])
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; CHECK-NEXT: ret float [[R]]
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;
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%m = fmul float %x, 42.0
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%r = fsub float -0.0, %m
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call void @use(float %m)
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ret float %r
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}
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; Try a vector. Use special constants (NaN, INF, undef) because they don't change anything.
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define <4 x double> @fmul_fneg_vec(<4 x double> %x) {
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; CHECK-LABEL: @fmul_fneg_vec(
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; CHECK-NEXT: [[R:%.*]] = fmul <4 x double> [[X:%.*]], <double -4.200000e+01, double 0x7F80000000000000, double 0xFFF0000000000000, double 0x7FF8000000000000>
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; CHECK-NEXT: ret <4 x double> [[R]]
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;
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%m = fmul <4 x double> %x, <double 42.0, double 0x7FF80000000000000, double 0x7FF0000000000000, double undef>
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%r = fsub <4 x double> <double -0.0, double -0.0, double -0.0, double -0.0>, %m
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ret <4 x double> %r
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}
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; -(X / C) --> X / (-C)
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define float @fdiv_op1_constant_fneg(float %x) {
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; CHECK-LABEL: @fdiv_op1_constant_fneg(
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; CHECK-NEXT: [[R:%.*]] = fdiv float [[X:%.*]], 4.200000e+01
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; CHECK-NEXT: ret float [[R]]
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;
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%d = fdiv float %x, -42.0
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%r = fsub float -0.0, %d
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ret float %r
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}
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; Fast math is not required, but it should be propagated.
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define float @fdiv_op1_constant_fneg_fmf(float %x) {
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; CHECK-LABEL: @fdiv_op1_constant_fneg_fmf(
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; CHECK-NEXT: [[R:%.*]] = fdiv nnan float [[X:%.*]], 4.200000e+01
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; CHECK-NEXT: ret float [[R]]
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;
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%d = fdiv float %x, -42.0
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%r = fsub nnan float -0.0, %d
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ret float %r
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}
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; Extra use prevents the fold. We don't want to replace the fneg with an fdiv.
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define float @fdiv_op1_constant_fneg_extra_use(float %x) {
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; CHECK-LABEL: @fdiv_op1_constant_fneg_extra_use(
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; CHECK-NEXT: [[D:%.*]] = fdiv float [[X:%.*]], 4.200000e+01
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; CHECK-NEXT: [[R:%.*]] = fsub float -0.000000e+00, [[D]]
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; CHECK-NEXT: call void @use(float [[D]])
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; CHECK-NEXT: ret float [[R]]
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;
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%d = fdiv float %x, 42.0
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%r = fsub float -0.0, %d
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call void @use(float %d)
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ret float %r
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}
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; Try a vector. Use special constants (NaN, INF, undef) because they don't change anything.
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define <4 x double> @fdiv_op1_constant_fneg_vec(<4 x double> %x) {
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; CHECK-LABEL: @fdiv_op1_constant_fneg_vec(
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; CHECK-NEXT: [[R:%.*]] = fdiv <4 x double> [[X:%.*]], <double 4.200000e+01, double 0x7FF800000ABCD000, double 0x7FF0000000000000, double 0x7FF8000000000000>
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; CHECK-NEXT: ret <4 x double> [[R]]
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;
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%d = fdiv <4 x double> %x, <double -42.0, double 0xFFF800000ABCD000, double 0xFFF0000000000000, double undef>
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%r = fsub <4 x double> <double -0.0, double -0.0, double -0.0, double -0.0>, %d
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ret <4 x double> %r
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}
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; -(C / X) --> (-C) / X
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define float @fdiv_op0_constant_fneg(float %x) {
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; CHECK-LABEL: @fdiv_op0_constant_fneg(
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; CHECK-NEXT: [[R:%.*]] = fdiv float -4.200000e+01, [[X:%.*]]
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; CHECK-NEXT: ret float [[R]]
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;
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%d = fdiv float 42.0, %x
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%r = fsub float -0.0, %d
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ret float %r
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}
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; Fast math is not required, but it should be propagated.
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define float @fdiv_op0_constant_fneg_fmf(float %x) {
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; CHECK-LABEL: @fdiv_op0_constant_fneg_fmf(
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; CHECK-NEXT: [[R:%.*]] = fdiv fast float -4.200000e+01, [[X:%.*]]
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; CHECK-NEXT: ret float [[R]]
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;
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%d = fdiv float 42.0, %x
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%r = fsub fast float -0.0, %d
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ret float %r
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}
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; Extra use prevents the fold. We don't want to replace the fneg with an fdiv.
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define float @fdiv_op0_constant_fneg_extra_use(float %x) {
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; CHECK-LABEL: @fdiv_op0_constant_fneg_extra_use(
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; CHECK-NEXT: [[D:%.*]] = fdiv float -4.200000e+01, [[X:%.*]]
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; CHECK-NEXT: [[R:%.*]] = fsub float -0.000000e+00, [[D]]
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; CHECK-NEXT: call void @use(float [[D]])
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; CHECK-NEXT: ret float [[R]]
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;
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%d = fdiv float -42.0, %x
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%r = fsub float -0.0, %d
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call void @use(float %d)
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ret float %r
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}
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; Try a vector. Use special constants (NaN, INF, undef) because they don't change anything.
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define <4 x double> @fdiv_op0_constant_fneg_vec(<4 x double> %x) {
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; CHECK-LABEL: @fdiv_op0_constant_fneg_vec(
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; CHECK-NEXT: [[R:%.*]] = fdiv <4 x double> <double 4.200000e+01, double 0x7F80000000000000, double 0x7FF0000000000000, double 0x7FF8000000000000>, [[X:%.*]]
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; CHECK-NEXT: ret <4 x double> [[R]]
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;
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%d = fdiv <4 x double> <double -42.0, double 0x7FF80000000000000, double 0xFFF0000000000000, double undef>, %x
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%r = fsub <4 x double> <double -0.0, double -0.0, double -0.0, double -0.0>, %d
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ret <4 x double> %r
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}
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