Add a testcase for r135123.

Part of rdar://9761830

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135133 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CodeGen/ARM/fold-const.ll b/test/CodeGen/ARM/fold-const.ll
new file mode 100644 (file)
index 0000000..227e4e8
--- /dev/null
+++ b/test/CodeGen/ARM/fold-const.ll
@@ -0,0 +1,14 @@
+; RUN: llc < %s -march=arm -mattr=+v7 | FileCheck %s
+
+define i32 @f(i32 %a) nounwind readnone optsize ssp {
+entry:
+  %conv = zext i32 %a to i64
+  %tmp1 = tail call i64 @llvm.ctlz.i64(i64 %conv)
+; CHECK: clz
+; CHECK-NOT: adds
+  %cast = trunc i64 %tmp1 to i32
+  %sub = sub nsw i32 63, %cast
+  ret i32 %sub
+}
+
+declare i64 @llvm.ctlz.i64(i64) nounwind readnone