Make sure we don't return bits outside the mask in ComputeMaskedBits. PR12189.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152066 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/InstSimplify/phi.ll

@@ -0,0 +1,22 @@
+; RUN: opt < %s -instsimplify -S | FileCheck %s
+
+; PR12189
+define i1 @test1(i32 %x) {
+; CHECK: @test1
+  br i1 true, label %a, label %b
+
+a:
+  %aa = or i32 %x, 10
+  br label %c
+
+b:
+  %bb = or i32 %x, 10
+  br label %c
+
+c:
+  %cc = phi i32 [ %bb, %b ], [%aa, %a ]
+  %d = urem i32 %cc, 2
+  %e = icmp eq i32 %d, 0
+  ret i1 %e
+; CHECK: ret i1 %e
+}