[llvm] r289895 - [SimplifyLibCalls] Add a test to make sure we lower fls(0) correctly.

[Davide Italiano via llvm-commits]

Author: davide
Date: Thu Dec 15 17:48:07 2016
New Revision: 289895

URL: http://llvm.org/viewvc/llvm-project?rev=289895&view=rev
Log:
[SimplifyLibCalls] Add a test to make sure we lower fls(0) correctly.

Modified:
    llvm/trunk/test/Transforms/InstCombine/fls.ll

Modified: llvm/trunk/test/Transforms/InstCombine/fls.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fls.ll?rev=289895&r1=289894&r2=289895&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fls.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/fls.ll Thu Dec 15 17:48:07 2016
@@ -43,6 +43,15 @@ define i32 @flsnotconst(i64 %z) {
   ret i32 %goo
 }
 
+; Make sure we lower fls(0) to 0 and not to `undef`.
+; CHECK-LABEL: define i32 @flszero(
+; CHECK: ret i32 0
+; CHECK: }
+define i32 @flszero() {
+  %zero = call i32 @fls(i32 0)
+  ret i32 %zero
+}
+
 declare i32 @fls(i32)
 declare i32 @flsl(i64)
 declare i32 @flsll(i64)