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[SimplifyLibCalls] Add a test to make sure we lower fls(0) correctly.
authorDavide Italiano <davide@freebsd.org>
Thu, 15 Dec 2016 23:48:07 +0000 (23:48 +0000)
committerDavide Italiano <davide@freebsd.org>
Thu, 15 Dec 2016 23:48:07 +0000 (23:48 +0000)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289895 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/InstCombine/fls.ll

index bf608b3..9ccc56a 100644 (file)
@@ -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)