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      1 ; Test that the strstr library call simplifier works correctly.
      2 ;
      3 ; RUN: opt < %s -instcombine -S | FileCheck %s
      4 
      5 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
      6 
      7 @.str = private constant [1 x i8] zeroinitializer
      8 @.str1 = private constant [2 x i8] c"a\00"
      9 @.str2 = private constant [6 x i8] c"abcde\00"
     10 @.str3 = private constant [4 x i8] c"bcd\00"
     11 
     12 declare i8* @strstr(i8*, i8*)
     13 
     14 ; Check strstr(str, "") -> str.
     15 
     16 define i8* @test_simplify1(i8* %str) {
     17 ; CHECK-LABEL: @test_simplify1(
     18   %pat = getelementptr inbounds [1 x i8]* @.str, i32 0, i32 0
     19   %ret = call i8* @strstr(i8* %str, i8* %pat)
     20   ret i8* %ret
     21 ; CHECK-NEXT: ret i8* %str
     22 }
     23 
     24 ; Check strstr(str, "a") -> strchr(str, 'a').
     25 
     26 define i8* @test_simplify2(i8* %str) {
     27 ; CHECK-LABEL: @test_simplify2(
     28   %pat = getelementptr inbounds [2 x i8]* @.str1, i32 0, i32 0
     29   %ret = call i8* @strstr(i8* %str, i8* %pat)
     30   ret i8* %ret
     31 ; CHECK-NEXT: @strchr(i8* %str, i32 97)
     32 }
     33 
     34 ; Check strstr("abcde", "bcd") -> "abcde" + 1.
     35 
     36 define i8* @test_simplify3() {
     37 ; CHECK-LABEL: @test_simplify3(
     38   %str = getelementptr inbounds [6 x i8]* @.str2, i32 0, i32 0
     39   %pat = getelementptr inbounds [4 x i8]* @.str3, i32 0, i32 0
     40   %ret = call i8* @strstr(i8* %str, i8* %pat)
     41   ret i8* %ret
     42 ; CHECK-NEXT: getelementptr inbounds ([6 x i8]* @.str2, i64 0, i64 1)
     43 }
     44 
     45 ; Check strstr(str, str) -> str.
     46 
     47 define i8* @test_simplify4(i8* %str) {
     48 ; CHECK-LABEL: @test_simplify4(
     49   %ret = call i8* @strstr(i8* %str, i8* %str)
     50   ret i8* %ret
     51 ; CHECK-NEXT: ret i8* %str
     52 }
     53 
     54 ; Check strstr(str, pat) == str -> strncmp(str, pat, strlen(str)) == 0.
     55 
     56 define i1 @test_simplify5(i8* %str, i8* %pat) {
     57 ; CHECK-LABEL: @test_simplify5(
     58   %ret = call i8* @strstr(i8* %str, i8* %pat)
     59   %cmp = icmp eq i8* %ret, %str
     60   ret i1 %cmp
     61 ; CHECK: [[LEN:%[a-z]+]] = call {{i[0-9]+}} @strlen(i8* %pat)
     62 ; CHECK: [[NCMP:%[a-z]+]] = call {{i[0-9]+}} @strncmp(i8* %str, i8* %pat, {{i[0-9]+}} [[LEN]])
     63 ; CHECK: icmp eq {{i[0-9]+}} [[NCMP]], 0
     64 ; CHECK: ret i1
     65 }
     66