Generalize the zext(trunc(t) & C) instcombine to work even with

C is not a low-bits mask, and add a similar instcombine for
zext((trunc(t) & C) ^ C).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73705 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 1 deletions

diff --git a/test/Transforms/InstCombine/trunc-mask-ext.ll b/test/Transforms/InstCombine/trunc-mask-ext.ll
index 1499947..7e3d844 100644
--- a/test/Transforms/InstCombine/trunc-mask-ext.ll
+++ b/test/Transforms/InstCombine/trunc-mask-ext.ll
@@ -2,7 +2,7 @@
 ; RUN: not grep zext %t
 ; RUN: not grep sext %t
 
-; Instcombine should be able to eliminate both ext casts.
+; Instcombine should be able to eliminate all of these ext casts.
 
 declare void @use(i32)
 
@@ -21,3 +21,18 @@ define i64 @bar(i64 %a) {
   call void @use(i32 %b)
   ret i64 %d
 }
+define i64 @goo(i64 %a) {
+  %b = trunc i64 %a to i32
+  %c = and i32 %b, 8
+  %d = zext i32 %c to i64
+  call void @use(i32 %b)
+  ret i64 %d
+}
+define i64 @hoo(i64 %a) {
+  %b = trunc i64 %a to i32
+  %c = and i32 %b, 8
+  %x = xor i32 %c, 8
+  %d = zext i32 %x to i64
+  call void @use(i32 %b)
+  ret i64 %d
+}