Fast-math test for SimplifyInstruction: fold multiply by 0

Applied the patch, rather than committing it.

llvm-svn: 168656

1 files changed, 35 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstSimplify/fast-math.ll b/llvm/test/Transforms/InstSimplify/fast-math.ll
new file mode 100644
index 00000000000..e4b3ea306a1
--- /dev/null
+++ b/llvm/test/Transforms/InstSimplify/fast-math.ll
@@ -0,0 +1,35 @@
+; RUN: opt < %s -instsimplify -S | FileCheck %s
+
+;; x * 0 ==> 0 when no-nans and no-signed-zero
+; CHECK: mul_zero_1
+define float @mul_zero_1(float %a) {
+  %b = fmul nsz nnan float %a, 0.0
+; CHECK: ret float 0.0
+  ret float %b
+}
+; CHECK: mul_zero_2
+define float @mul_zero_2(float %a) {
+  %b = fmul fast float 0.0, %a
+; CHECK: ret float 0.0
+  ret float %b
+}
+
+;; x * 0 =/=> 0 when there could be nans or -0
+; CHECK: no_mul_zero_1
+define float @no_mul_zero_1(float %a) {
+  %b = fmul nsz float %a, 0.0
+; CHECK: ret float %b
+  ret float %b
+}
+; CHECK: no_mul_zero_2
+define float @no_mul_zero_2(float %a) {
+  %b = fmul nnan float %a, 0.0
+; CHECK: ret float %b
+  ret float %b
+}
+; CHECK: no_mul_zero_3
+define float @no_mul_zero_3(float %a) {
+  %b = fmul float %a, 0.0
+; CHECK: ret float %b
+  ret float %b
+}