Simplify (A & ~B) in icmp if A is a power of 2

The transform will execute like so:
(A & ~B) == 0 --> (A & B) != 0
(A & ~B) != 0 --> (A & B) == 0


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179386 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 26 insertions, 0 deletions

diff --git a/test/Transforms/InstCombine/icmp.ll b/test/Transforms/InstCombine/icmp.ll
index 28fa33b..74adbba 100644
--- a/test/Transforms/InstCombine/icmp.ll
+++ b/test/Transforms/InstCombine/icmp.ll
@@ -938,3 +938,29 @@ define i1 @icmp_sub57_sge_sub20(i32 %x, i32 %y) {
   %cmp = icmp sge i32 %1, %2
   ret i1 %cmp
 }
+
+; CHECK: @icmp_and_shl_neg_ne_0
+; CHECK-NEXT: [[SHL:%[a-z0-9]+]] = shl i32 1, %B
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 [[SHL]], %A
+; CHECK-NEXT: [[CMP:%[a-z0-9]+]] = icmp eq i32 [[AND]], 0
+; CHECK-NEXT: ret i1 [[CMP]]
+define i1 @icmp_and_shl_neg_ne_0(i32 %A, i32 %B) {
+  %neg = xor i32 %A, -1
+  %shl = shl i32 1, %B
+  %and = and i32 %shl, %neg
+  %cmp = icmp ne i32 %and, 0
+  ret i1 %cmp
+}
+
+; CHECK: @icmp_and_shl_neg_eq_0
+; CHECK-NEXT: [[SHL:%[a-z0-9]+]] = shl i32 1, %B
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 [[SHL]], %A
+; CHECK-NEXT: [[CMP:%[a-z0-9]+]] = icmp ne i32 [[AND]], 0
+; CHECK-NEXT: ret i1 [[CMP]]
+define i1 @icmp_and_shl_neg_eq_0(i32 %A, i32 %B) {
+  %neg = xor i32 %A, -1
+  %shl = shl i32 1, %B
+  %and = and i32 %shl, %neg
+  %cmp = icmp eq i32 %and, 0
+  ret i1 %cmp
+}