[InstCombine] add tests for fneg of fmul/fdiv with constant; NFC

llvm-svn: 339195

1 files changed, 128 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/fneg.ll b/llvm/test/Transforms/InstCombine/fneg.ll
new file mode 100644
index 00000000000..bd8ed121127
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/fneg.ll
@@ -0,0 +1,128 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+declare void @use(float)
+
+; -(X * C) --> X * (-C)
+
+define float @fmul_fneg(float %x) {
+; CHECK-LABEL: @fmul_fneg(
+; CHECK-NEXT:    [[M:%.*]] = fmul float [[X:%.*]], 4.200000e+01
+; CHECK-NEXT:    [[R:%.*]] = fsub float -0.000000e+00, [[M]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %m = fmul float %x, 42.0
+  %r = fsub float -0.0, %m
+  ret float %r
+}
+
+; Extra use is ok.
+
+define float @fmul_fneg_extra_use(float %x) {
+; CHECK-LABEL: @fmul_fneg_extra_use(
+; CHECK-NEXT:    [[M:%.*]] = fmul float [[X:%.*]], 4.200000e+01
+; CHECK-NEXT:    [[R:%.*]] = fsub float -0.000000e+00, [[M]]
+; CHECK-NEXT:    call void @use(float [[M]])
+; CHECK-NEXT:    ret float [[R]]
+;
+  %m = fmul float %x, 42.0
+  %r = fsub float -0.0, %m
+  call void @use(float %m)
+  ret float %r
+}
+
+; Try a vector. Use special constants (NaN, INF, undef) because they don't change anything.
+
+define <4 x double> @fmul_fneg_vec(<4 x double> %x) {
+; CHECK-LABEL: @fmul_fneg_vec(
+; CHECK-NEXT:    [[M:%.*]] = fmul <4 x double> [[X:%.*]], <double 4.200000e+01, double 0xFF80000000000000, double 0x7FF0000000000000, double undef>
+; CHECK-NEXT:    [[R:%.*]] = fsub <4 x double> <double -0.000000e+00, double -0.000000e+00, double -0.000000e+00, double -0.000000e+00>, [[M]]
+; CHECK-NEXT:    ret <4 x double> [[R]]
+;
+  %m = fmul <4 x double> %x, <double 42.0, double 0x7FF80000000000000, double 0x7FF0000000000000, double undef>
+  %r = fsub <4 x double> <double -0.0, double -0.0, double -0.0, double -0.0>, %m
+  ret <4 x double> %r
+}
+
+; -(X / C) --> X / (-C)
+
+define float @fdiv_op1_constant_fneg(float %x) {
+; CHECK-LABEL: @fdiv_op1_constant_fneg(
+; CHECK-NEXT:    [[D:%.*]] = fdiv float [[X:%.*]], -4.200000e+01
+; CHECK-NEXT:    [[R:%.*]] = fsub float -0.000000e+00, [[D]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %d = fdiv float %x, -42.0
+  %r = fsub float -0.0, %d
+  ret float %r
+}
+
+; Extra use is ok.
+
+define float @fdiv_op1_constant_fneg_extra_use(float %x) {
+; CHECK-LABEL: @fdiv_op1_constant_fneg_extra_use(
+; CHECK-NEXT:    [[D:%.*]] = fdiv float [[X:%.*]], 4.200000e+01
+; CHECK-NEXT:    [[R:%.*]] = fsub float -0.000000e+00, [[D]]
+; CHECK-NEXT:    call void @use(float [[D]])
+; CHECK-NEXT:    ret float [[R]]
+;
+  %d = fdiv float %x, 42.0
+  %r = fsub float -0.0, %d
+  call void @use(float %d)
+  ret float %r
+}
+
+; Try a vector. Use special constants (NaN, INF, undef) because they don't change anything.
+
+define <4 x double> @fdiv_op1_constant_fneg_vec(<4 x double> %x) {
+; CHECK-LABEL: @fdiv_op1_constant_fneg_vec(
+; CHECK-NEXT:    [[D:%.*]] = fdiv <4 x double> [[X:%.*]], <double -4.200000e+01, double 0.000000e+00, double 0xFFF0000000000000, double undef>
+; CHECK-NEXT:    [[R:%.*]] = fsub <4 x double> <double -0.000000e+00, double -0.000000e+00, double -0.000000e+00, double -0.000000e+00>, [[D]]
+; CHECK-NEXT:    ret <4 x double> [[R]]
+;
+  %d = fdiv <4 x double> %x, <double -42.0, double 0xFFF800000ABCD0000, double 0xFFF0000000000000, double undef>
+  %r = fsub <4 x double> <double -0.0, double -0.0, double -0.0, double -0.0>, %d
+  ret <4 x double> %r
+}
+
+; -(C / X) --> (-C) / X
+
+define float @fdiv_op0_constant_fneg(float %x) {
+; CHECK-LABEL: @fdiv_op0_constant_fneg(
+; CHECK-NEXT:    [[D:%.*]] = fdiv float 4.200000e+01, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub float -0.000000e+00, [[D]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %d = fdiv float 42.0, %x
+  %r = fsub float -0.0, %d
+  ret float %r
+}
+
+; Extra use is ok.
+
+define float @fdiv_op0_constant_fneg_extra_use(float %x) {
+; CHECK-LABEL: @fdiv_op0_constant_fneg_extra_use(
+; CHECK-NEXT:    [[D:%.*]] = fdiv float -4.200000e+01, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub float -0.000000e+00, [[D]]
+; CHECK-NEXT:    call void @use(float [[D]])
+; CHECK-NEXT:    ret float [[R]]
+;
+  %d = fdiv float -42.0, %x
+  %r = fsub float -0.0, %d
+  call void @use(float %d)
+  ret float %r
+}
+
+; Try a vector. Use special constants (NaN, INF, undef) because they don't change anything.
+
+define <4 x double> @fdiv_op0_constant_fneg_vec(<4 x double> %x) {
+; CHECK-LABEL: @fdiv_op0_constant_fneg_vec(
+; CHECK-NEXT:    [[D:%.*]] = fdiv <4 x double> <double -4.200000e+01, double 0xFF80000000000000, double 0xFFF0000000000000, double undef>, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub <4 x double> <double -0.000000e+00, double -0.000000e+00, double -0.000000e+00, double -0.000000e+00>, [[D]]
+; CHECK-NEXT:    ret <4 x double> [[R]]
+;
+  %d = fdiv <4 x double> <double -42.0, double 0x7FF80000000000000, double 0xFFF0000000000000, double undef>, %x
+  %r = fsub <4 x double> <double -0.0, double -0.0, double -0.0, double -0.0>, %d
+  ret <4 x double> %r
+}
+