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      1 ; Test that the strncpy library call simplifier works correctly.
      2 ;
      3 ; RUN: opt < %s -instcombine -S | FileCheck %s
      4 
      5 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"
      6 
      7 @hello = constant [6 x i8] c"hello\00"
      8 @null = constant [1 x i8] zeroinitializer
      9 @null_hello = constant [7 x i8] c"\00hello\00"
     10 @a = common global [32 x i8] zeroinitializer, align 1
     11 @b = common global [32 x i8] zeroinitializer, align 1
     12 
     13 declare i8* @strncpy(i8*, i8*, i32)
     14 declare i32 @puts(i8*)
     15 
     16 ; Check a bunch of strncpy invocations together.
     17 
     18 define i32 @test_simplify1() {
     19 ; CHECK-LABEL: @test_simplify1(
     20 ; CHECK-NOT: call i8* @strncpy
     21 ; CHECK: call i32 @puts
     22   %target = alloca [1024 x i8]
     23   %arg1 = getelementptr [1024 x i8], [1024 x i8]* %target, i32 0, i32 0
     24   store i8 0, i8* %arg1
     25 
     26   %arg2 = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
     27   %rslt1 = call i8* @strncpy(i8* %arg1, i8* %arg2, i32 6)
     28 
     29   %arg3 = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
     30   %rslt2 = call i8* @strncpy(i8* %rslt1, i8* %arg3, i32 42)
     31 
     32   %arg4 = getelementptr [7 x i8], [7 x i8]* @null_hello, i32 0, i32 0
     33   %rslt3 = call i8* @strncpy(i8* %rslt2, i8* %arg4, i32 42)
     34 
     35   call i32 @puts( i8* %rslt3 )
     36   ret i32 0
     37 }
     38 
     39 ; Check strncpy(x, "", y) -> memset(x, '\0', y, 1).
     40 
     41 define void @test_simplify2() {
     42 ; CHECK-LABEL: @test_simplify2(
     43   %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
     44   %src = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
     45 
     46   call i8* @strncpy(i8* %dst, i8* %src, i32 32)
     47 ; CHECK: call void @llvm.memset.p0i8.i32
     48   ret void
     49 }
     50 
     51 ; Check strncpy(x, y, 0) -> x.
     52 
     53 define i8* @test_simplify3() {
     54 ; CHECK-LABEL: @test_simplify3(
     55   %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
     56   %src = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
     57 
     58   %ret = call i8* @strncpy(i8* %dst, i8* %src, i32 0)
     59   ret i8* %ret
     60 ; CHECK: ret i8* getelementptr inbounds ([32 x i8], [32 x i8]* @a, i32 0, i32 0)
     61 }
     62 
     63 ; Check  strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant].
     64 
     65 define void @test_simplify4() {
     66 ; CHECK-LABEL: @test_simplify4(
     67   %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
     68   %src = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
     69 
     70   call i8* @strncpy(i8* %dst, i8* %src, i32 6)
     71 ; CHECK: call void @llvm.memcpy.p0i8.p0i8.i32
     72   ret void
     73 }
     74 
     75 ; Check cases that shouldn't be simplified.
     76 
     77 define void @test_no_simplify1() {
     78 ; CHECK-LABEL: @test_no_simplify1(
     79   %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
     80   %src = getelementptr [32 x i8], [32 x i8]* @b, i32 0, i32 0
     81 
     82   call i8* @strncpy(i8* %dst, i8* %src, i32 32)
     83 ; CHECK: call i8* @strncpy
     84   ret void
     85 }
     86 
     87 define void @test_no_simplify2() {
     88 ; CHECK-LABEL: @test_no_simplify2(
     89   %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
     90   %src = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
     91 
     92   call i8* @strncpy(i8* %dst, i8* %src, i32 8)
     93 ; CHECK: call i8* @strncpy
     94   ret void
     95 }
     96