Add a generic expansion transform: A op (B op' C) -> (A op B) op' (A op C)

if both A op B and A op C simplify.  This fires fairly often but doesn't
make that much difference.  On gcc-as-one-file it removes two "and"s and
turns one branch into a select.

llvm-svn: 122399

1 files changed, 14 insertions, 2 deletions

diff --git a/llvm/test/Transforms/InstCombine/2010-11-23-Distributed.ll b/llvm/test/Transforms/InstCombine/2010-11-23-Distributed.ll
index 13a5720dad2..4f8e8dc713b 100644
--- a/llvm/test/Transforms/InstCombine/2010-11-23-Distributed.ll
+++ b/llvm/test/Transforms/InstCombine/2010-11-23-Distributed.ll
@@ -5,7 +5,19 @@ define i32 @foo(i32 %x, i32 %y) {
   %mul = mul nsw i32 %add, %y
   %square = mul nsw i32 %y, %y
   %res = sub i32 %mul, %square
-; CHECK: %res = mul i32 %x, %y
   ret i32 %res
-; CHECK: ret i32 %res
+; CHECK-NEXT: mul i32 %x, %y
+; CHECK-NEXT: ret i32
+}
+
+define i1 @bar(i64 %x, i64 %y) {
+; CHECK: @bar
+  %a = and i64 %y, %x
+; CHECK: and
+; CHECK-NOT: and
+  %not = xor i64 %a, -1
+  %b = and i64 %y, %not
+  %r = icmp eq i64 %b, 0
+  ret i1 %r
+; CHECK: ret i1
 }