* Add a test case for StrLenOptimization

* Rename ExitInMain and StrCat tests so they don't have the date the
  regression was entered since they are feature tests, not regressions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21558 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/SimplifyLibCalls/StrLen.ll

@@ -0,0 +1,21 @@
+; Test that the StrCatOptimizer works correctly
+; RUN: llvm-as < %s | opt -simplify-libcalls | llvm-dis | not grep 'call.*strlen'
+
+declare int %strlen(sbyte*)
+%hello = constant [6 x sbyte] c"hello\00"
+%null = constant [1 x sbyte] c"\00"
+%null_hello = constant [7 x sbyte] c"\00hello\00"
+
+implementation   ; Functions:
+
+int %main () {
+  %hello_p = getelementptr [6 x sbyte]* %hello, int 0, int 0
+  %hello_l = call int %strlen(sbyte* %hello_p)
+  %null_p = getelementptr [1 x sbyte]* %null, int 0, int 0
+  %null_l = call int %strlen(sbyte* %null_p)
+  %null_hello_p = getelementptr [7 x sbyte]* %null_hello, int 0, int 0
+  %null_hello_l = call int %strlen(sbyte* %null_hello_p)
+  %sum1 = add int %hello_l, %null_l
+  %sum2 = add int %sum1, %null_hello_l
+  ret int %sum2
+}