[InstSimplify] Add self-fdiv identities for -ffinite-math-only.

When NaNs and Infs are ignored we can fold
 X /  X -> 1.0
-X /  X -> -1.0
 X / -X -> -1.0

llvm-svn: 239701

1 files changed, 77 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstSimplify/fast-math.ll b/llvm/test/Transforms/InstSimplify/fast-math.ll
index e7fb14d7e78..0336301c354 100644
--- a/llvm/test/Transforms/InstSimplify/fast-math.ll
+++ b/llvm/test/Transforms/InstSimplify/fast-math.ll
@@ -114,3 +114,80 @@ define double @fdiv_zero_by_x(double %X) {
   ret double %r
 ; CHECK: ret double 0
 }
+
+define float @fdiv_self(float %f)  {
+  %div = fdiv nnan ninf float %f, %f
+  ret float %div
+; CHECK-LABEL: fdiv_self
+; CHECK: ret float 1.000000e+00
+}
+
+define float @fdiv_self_invalid1(float %f)  {
+  %div = fdiv ninf float %f, %f
+  ret float %div
+; CHECK-LABEL: fdiv_self_invalid1
+; CHECK: %div = fdiv ninf float %f, %f
+; CHECK-NEXT: ret float %div
+}
+
+define float @fdiv_self_invalid2(float %f)  {
+  %div = fdiv nnan float %f, %f
+  ret float %div
+; CHECK-LABEL: fdiv_self_invalid2
+; CHECK: %div = fdiv nnan float %f, %f
+; CHECK-NEXT: ret float %div
+}
+
+define float @fdiv_self_invalid3(float %f)  {
+  %div = fdiv float %f, %f
+  ret float %div
+; CHECK-LABEL: fdiv_self_invalid3
+; CHECK: %div = fdiv float %f, %f
+; CHECK-NEXT: ret float %div
+}
+
+define float @fdiv_neg(float %f) {
+  %neg = fsub fast float -0.000000e+00, %f
+  %div = fdiv nnan ninf float %neg, %f
+  ret float %div
+; CHECK-LABEL: fdiv_neg
+; CHECK: ret float -1.000000e+00
+}
+
+define float @fdiv_neg_invalid1(float %f) {
+  %neg = fsub fast float -0.000000e+00, %f
+  %div = fdiv ninf float %neg, %f
+  ret float %div
+; CHECK-LABEL: fdiv_neg_invalid1
+; CHECK: %neg = fsub fast float -0.000000e+00, %f
+; CHECK-NEXT: %div = fdiv ninf float %neg, %f
+; CHECK-NEXT: ret float %div
+}
+
+define float @fdiv_neg_invalid2(float %f) {
+  %neg = fsub fast float -0.000000e+00, %f
+  %div = fdiv nnan float %neg, %f
+  ret float %div
+; CHECK-LABEL: fdiv_neg_invalid2
+; CHECK: %neg = fsub fast float -0.000000e+00, %f
+; CHECK-NEXT: %div = fdiv nnan float %neg, %f
+; CHECK-NEXT: ret float %div
+}
+
+define float @fdiv_neg_invalid3(float %f) {
+  %neg = fsub fast float -0.000000e+00, %f
+  %div = fdiv float %neg, %f
+  ret float %div
+; CHECK-LABEL: fdiv_neg_invalid3
+; CHECK: %neg = fsub fast float -0.000000e+00, %f
+; CHECK-NEXT: %div = fdiv float %neg, %f
+; CHECK-NEXT: ret float %div
+}
+
+define float @fdiv_neg_swapped(float %f) {
+  %neg = fsub float 0.000000e+00, %f
+  %div = fdiv nnan ninf float %f, %neg
+  ret float %div
+; CHECK-LABEL: fdiv_neg_swapped
+; CHECK: ret float -1.000000e+00
+}