third_party/llvm-7.0/llvm/test/Transforms/InstCombine/strcspn-1.ll

; Test that the strcspn library call simplifier works correctly.
;
; RUN: opt < %s -instcombine -S | FileCheck %s

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"

@abcba = constant [6 x i8] c"abcba\00"
@abc = constant [4 x i8] c"abc\00"
@null = constant [1 x i8] zeroinitializer

declare i64 @strcspn(i8*, i8*)

; Check strcspn(s, "") -> strlen(s).

define i64 @test_simplify1(i8* %str) {
; CHECK-LABEL: @test_simplify1(
  %pat = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0

  %ret = call i64 @strcspn(i8* %str, i8* %pat)
; CHECK-NEXT: [[VAR:%[a-z]+]] = call i64 @strlen(i8* %str)
  ret i64 %ret
; CHECK-NEXT: ret i64 [[VAR]]
}

; Check strcspn("", s) -> 0.

define i64 @test_simplify2(i8* %pat) {
; CHECK-LABEL: @test_simplify2(
  %str = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0

  %ret = call i64 @strcspn(i8* %str, i8* %pat)
  ret i64 %ret
; CHECK-NEXT: ret i64 0
}

; Check strcspn(s1, s2), where s1 and s2 are constants.

define i64 @test_simplify3() {
; CHECK-LABEL: @test_simplify3(
  %str = getelementptr [6 x i8], [6 x i8]* @abcba, i32 0, i32 0
  %pat = getelementptr [4 x i8], [4 x i8]* @abc, i32 0, i32 0

  %ret = call i64 @strcspn(i8* %str, i8* %pat)
  ret i64 %ret
; CHECK-NEXT: ret i64 0
}

; Check cases that shouldn't be simplified.

define i64 @test_no_simplify1(i8* %str, i8* %pat) {
; CHECK-LABEL: @test_no_simplify1(

  %ret = call i64 @strcspn(i8* %str, i8* %pat)
; CHECK-NEXT: %ret = call i64 @strcspn(i8* %str, i8* %pat)
  ret i64 %ret
; CHECK-NEXT: ret i64 %ret
}