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llvm-mirror/test/Transforms/SimplifyLibCalls/StrNCmp.ll
Benjamin Kramer f600dc2eed simplify-libcalls: fold strncmp(x, y, 1) -> memcmp(x, y, 1)
The memcmp will be optimized further and even the pathological case
'strstr(x, "x") == x' generates optimal code now.

llvm-svn: 106097
2010-06-16 10:30:29 +00:00

36 lines
1.5 KiB
LLVM

; Test that the StrNCmpOptimizer works correctly
; RUN: opt < %s -simplify-libcalls -S | \
; RUN: not grep {call.*strncmp}
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
target triple = "i386-apple-darwin9.0"
@hello = constant [6 x i8] c"hello\00" ; <[6 x i8]*> [#uses=1]
@hell = constant [5 x i8] c"hell\00" ; <[5 x i8]*> [#uses=1]
@null = constant [1 x i8] zeroinitializer ; <[1 x i8]*> [#uses=1]
declare i32 @strncmp(i8*, i8*, i32)
declare i32 @puts(i8*)
define i32 @main() {
%hello_p = getelementptr [6 x i8]* @hello, i32 0, i32 0 ; <i8*> [#uses=5]
%hell_p = getelementptr [5 x i8]* @hell, i32 0, i32 0 ; <i8*> [#uses=1]
%null_p = getelementptr [1 x i8]* @null, i32 0, i32 0 ; <i8*> [#uses=4]
%temp1 = call i32 @strncmp( i8* %hello_p, i8* %hello_p, i32 5 ) ; <i32> [#uses=1]
%temp2 = call i32 @strncmp( i8* %null_p, i8* %null_p, i32 0 ) ; <i32> [#uses=1]
%temp3 = call i32 @strncmp( i8* %hello_p, i8* %null_p, i32 0 ) ; <i32> [#uses=1]
%temp4 = call i32 @strncmp( i8* %null_p, i8* %hello_p, i32 0 ) ; <i32> [#uses=1]
%temp5 = call i32 @strncmp( i8* %hell_p, i8* %hello_p, i32 4 ) ; <i32> [#uses=1]
%rslt1 = add i32 %temp1, %temp2 ; <i32> [#uses=1]
%rslt2 = add i32 %rslt1, %temp3 ; <i32> [#uses=1]
%rslt3 = add i32 %rslt2, %temp4 ; <i32> [#uses=1]
%rslt4 = add i32 %rslt3, %temp5 ; <i32> [#uses=1]
ret i32 %rslt4
}
define i32 @test1(i8* %P, i8* %Q) {
%cmp = call i32 @strncmp(i8* %P, i8* %Q, i32 1)
ret i32 %cmp
}