add some optimizations for strncpy/strncat and factor some

code.  Patch by Benjamin Kramer!

llvm-svn: 68885

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SimplifyLibCalls/StrNCat.ll b/llvm/test/Transforms/SimplifyLibCalls/StrNCat.ll
new file mode 100644
index 00000000000..0ce319c5e8f
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyLibCalls/StrNCat.ll
@@ -0,0 +1,27 @@
+; Test that the StrNCatOptimizer works correctly
+; RUN: llvm-as < %s | opt -simplify-libcalls | llvm-dis | \
+; RUN:   not grep {call.*strncat}
+; RUN: llvm-as < %s | opt -simplify-libcalls | llvm-dis | \
+; RUN:   grep {puts.*%arg1}
+
+@hello = constant [6 x i8] c"hello\00"		; <[6 x i8]*> [#uses=1]
+@null = constant [1 x i8] zeroinitializer		; <[1 x i8]*> [#uses=1]
+@null_hello = constant [7 x i8] c"\00hello\00"		; <[7 x i8]*> [#uses=1]
+
+declare i8* @strncat(i8*, i8*, i32)
+
+declare i32 @puts(i8*)
+
+define i32 @main() {
+	%target = alloca [1024 x i8]		; <[1024 x i8]*> [#uses=1]
+	%arg1 = getelementptr [1024 x i8]* %target, i32 0, i32 0		; <i8*> [#uses=2]
+	store i8 0, i8* %arg1
+	%arg2 = getelementptr [6 x i8]* @hello, i32 0, i32 0		; <i8*> [#uses=1]
+	%rslt1 = call i8* @strncat( i8* %arg1, i8* %arg2, i32 6 )		; <i8*> [#uses=1]
+	%arg3 = getelementptr [1 x i8]* @null, i32 0, i32 0		; <i8*> [#uses=1]
+	%rslt2 = call i8* @strncat( i8* %rslt1, i8* %arg3, i32 42 )		; <i8*> [#uses=1]
+	%arg4 = getelementptr [7 x i8]* @null_hello, i32 0, i32 0		; <i8*> [#uses=1]
+	%rslt3 = call i8* @strncat( i8* %rslt2, i8* %arg4, i32 42 )		; <i8*> [#uses=1]
+	call i32 @puts( i8* %rslt3 )		; <i32>:1 [#uses=0]
+	ret i32 0
+}