Fix missed optimization opportunity when analyzing cast of mul and select.

llvm-svn: 53151

1 files changed, 29 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/cast-mul-select.ll b/llvm/test/Transforms/InstCombine/cast-mul-select.ll
new file mode 100644
index 00000000000..76e9b24332f
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/cast-mul-select.ll
@@ -0,0 +1,29 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | notcast
+
+define i32 @mul(i32 %x, i32 %y) {
+  %A = trunc i32 %x to i8
+  %B = trunc i32 %y to i8
+  %C = mul i8 %A, %B
+  %D = zext i8 %C to i32
+  ret i32 %D
+}
+
+define i32 @select1(i1 %cond, i32 %x, i32 %y, i32 %z) {
+  %A = trunc i32 %x to i8
+  %B = trunc i32 %y to i8
+  %C = trunc i32 %z to i8
+  %D = add i8 %A, %B
+  %E = select i1 %cond, i8 %C, i8 %D
+  %F = zext i8 %E to i32
+  ret i32 %F
+}
+
+define i8 @select2(i1 %cond, i8 %x, i8 %y, i8 %z) {
+  %A = zext i8 %x to i32
+  %B = zext i8 %y to i32
+  %C = zext i8 %z to i32
+  %D = add i32 %A, %B
+  %E = select i1 %cond, i32 %C, i32 %D
+  %F = trunc i32 %E to i8
+  ret i8 %F
+}