test/Transforms/InstCombine/strncpy-1.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; Test that the strncpy library call simplifier works correctly.
;
; RUN: opt < %s -passes=instcombine -S | FileCheck %s

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"

@hello = constant [6 x i8] c"hello\00"
@null = constant [1 x i8] zeroinitializer
@null_hello = constant [7 x i8] c"\00hello\00"
@a = common global [32 x i8] zeroinitializer, align 1
@b = common global [32 x i8] zeroinitializer, align 1

declare ptr @strncpy(ptr, ptr, i32)
declare i32 @puts(ptr)

; Check a bunch of strncpy invocations together.

define i32 @test_simplify1() {
; CHECK-LABEL: @test_simplify1(
; CHECK-NEXT:    [[TARGET:%.*]] = alloca [1024 x i8], align 1
; CHECK-NEXT:    store i8 0, ptr [[TARGET]], align 1
; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr noundef nonnull align 1 dereferenceable(6) [[TARGET]], ptr noundef nonnull align 1 dereferenceable(6) @hello, i32 6, i1 false)
; CHECK-NEXT:    call void @llvm.memset.p0.i32(ptr noundef nonnull align 1 dereferenceable(42) [[TARGET]], i8 0, i32 42, i1 false)
; CHECK-NEXT:    call void @llvm.memset.p0.i32(ptr noundef nonnull align 1 dereferenceable(42) [[TARGET]], i8 0, i32 42, i1 false)
; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @puts(ptr noundef nonnull dereferenceable(1) [[TARGET]])
; CHECK-NEXT:    ret i32 0
;
  %target = alloca [1024 x i8]
  store i8 0, ptr %target

  %rslt1 = call ptr @strncpy(ptr %target, ptr @hello, i32 6)

  %rslt2 = call ptr @strncpy(ptr %rslt1, ptr @null, i32 42)

  %rslt3 = call ptr @strncpy(ptr %rslt2, ptr @null_hello, i32 42)

  call i32 @puts( ptr %rslt3 )
  ret i32 0
}

; Check strncpy(x, "", y) -> memset(x, '\0', y, 1).

define void @test_simplify2() {
; CHECK-LABEL: @test_simplify2(
; CHECK-NEXT:    call void @llvm.memset.p0.i32(ptr noundef nonnull align 1 dereferenceable(32) @a, i8 0, i32 32, i1 false)
; CHECK-NEXT:    ret void
;

  call ptr @strncpy(ptr @a, ptr @null, i32 32)
  ret void
}

; Check strncpy(x, y, 0) -> x.

define ptr @test_simplify3() {
; CHECK-LABEL: @test_simplify3(
; CHECK-NEXT:    ret ptr @a
;

  %ret = call ptr @strncpy(ptr @a, ptr @hello, i32 0)
  ret ptr %ret
}

; Check  strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant].

define void @test_simplify4() {
; CHECK-LABEL: @test_simplify4(
; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr noundef nonnull align 1 dereferenceable(6) @a, ptr noundef nonnull align 1 dereferenceable(6) @hello, i32 6, i1 false)
; CHECK-NEXT:    ret void
;

  call ptr @strncpy(ptr @a, ptr @hello, i32 6)
  ret void
}

define void @test_simplify5(ptr %dst) {
; CHECK-LABEL: @test_simplify5(
; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr noundef nonnull align 1 dereferenceable(32) [[DST:%.*]], ptr noundef nonnull align 1 dereferenceable(32) @str, i32 32, i1 false)
; CHECK-NEXT:    ret void
;
  call ptr @strncpy(ptr dereferenceable(8) %dst, ptr @hello, i32 32)
  ret void
}

define void @test_simplify6(ptr %dst) {
; CHECK-LABEL: @test_simplify6(
; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr noundef nonnull align 1 dereferenceable(80) [[DST:%.*]], ptr noundef nonnull align 1 dereferenceable(32) @str.1, i32 32, i1 false)
; CHECK-NEXT:    ret void
;
  call ptr @strncpy(ptr dereferenceable(80) %dst, ptr @hello, i32 32)
  ret void
}

define void @test_simplify7(ptr %dst, i32 %n) {
; CHECK-LABEL: @test_simplify7(
; CHECK-NEXT:    call void @llvm.memset.p0.i32(ptr align 1 dereferenceable(80) [[DST:%.*]], i8 0, i32 [[N:%.*]], i1 false)
; CHECK-NEXT:    ret void
;
; Unless N is known to be nonzero, strncpy(D, "", N) need not access any
; bytes in D.
; TODO: The argument, already annotated dereferenceable, should be
; annotated noundef and nonnull by the transformation.  See
; https://reviews.llvm.org/D124633.
  call ptr @strncpy(ptr dereferenceable(80) %dst, ptr @null, i32 %n)
  ret void
}

define ptr @test1(ptr %dst, ptr %src, i32 %n) {
; CHECK-LABEL: @test1(
; CHECK-NEXT:    [[RET:%.*]] = call ptr @strncpy(ptr nonnull [[DST:%.*]], ptr nonnull [[SRC:%.*]], i32 [[N:%.*]])
; CHECK-NEXT:    ret ptr [[RET]]
;
; Unless N is known to be nonzero, strncpy(D, S, N) need not access any
; bytes in either D or S.  Verify that the call isn't annotated with
; the dereferenceable attribute.
; TODO: Both arguments should be annotated noundef in addition to nonnull.
; See https://reviews.llvm.org/D124633.
  %ret = call ptr @strncpy(ptr nonnull %dst, ptr nonnull %src, i32 %n)
  ret ptr %ret
}

define ptr @test2(ptr %dst) {
; CHECK-LABEL: @test2(
; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr noundef nonnull align 1 dereferenceable(5) [[DST:%.*]], ptr noundef nonnull align 1 dereferenceable(6) @hello, i32 5, i1 false)
; CHECK-NEXT:    ret ptr [[DST]]
;
  %ret = call ptr @strncpy(ptr nonnull %dst, ptr nonnull @hello, i32 5)
  ret ptr %ret
}

define ptr @test3(ptr %dst, i32 %n) {
; CHECK-LABEL: @test3(
; CHECK-NEXT:    call void @llvm.memset.p0.i32(ptr noalias noundef nonnull align 1 dereferenceable(5) [[DST:%.*]], i8 0, i32 5, i1 false)
; CHECK-NEXT:    ret ptr [[DST]]
;
  %ret = call ptr @strncpy(ptr noalias nonnull %dst, ptr nonnull @null, i32 5);
  ret ptr %ret
}

define ptr @test4(ptr %dst, i32 %n) {
; CHECK-LABEL: @test4(
; CHECK-NEXT:    call void @llvm.memset.p0.i32(ptr noalias noundef nonnull align 16 dereferenceable(5) [[DST:%.*]], i8 0, i32 5, i1 false)
; CHECK-NEXT:    ret ptr [[DST]]
;
  %ret = call ptr @strncpy(ptr align(16) noalias nonnull %dst, ptr nonnull @null, i32 5);
  ret ptr %ret
}

; Check cases that shouldn't be simplified.

define void @test_no_simplify1() {
; CHECK-LABEL: @test_no_simplify1(
; CHECK-NEXT:    [[TMP1:%.*]] = call ptr @strncpy(ptr noundef nonnull dereferenceable(1) @a, ptr noundef nonnull dereferenceable(1) @b, i32 32)
; CHECK-NEXT:    ret void
;

  call ptr @strncpy(ptr @a, ptr @b, i32 32)
  ret void
}

define void @test_no_simplify2() {
; CHECK-LABEL: @test_no_simplify2(
; CHECK-NEXT:    store i64 478560413032, ptr @a, align 1
; CHECK-NEXT:    ret void
;

  call ptr @strncpy(ptr @a, ptr @hello, i32 8)
  ret void
}

define ptr @test_no_simplify3(ptr %dst, ptr %src, i32 %count) {
; CHECK-LABEL: @test_no_simplify3(
; CHECK-NEXT:    [[RET:%.*]] = musttail call ptr @strncpy(ptr [[DST:%.*]], ptr [[SRC:%.*]], i32 32)
; CHECK-NEXT:    ret ptr [[RET]]
;
  %ret = musttail call ptr @strncpy(ptr %dst, ptr %src, i32 32)
  ret ptr %ret
}

define ptr @test_no_simplify4(ptr %dst, ptr %src, i32 %count) {
; CHECK-LABEL: @test_no_simplify4(
; CHECK-NEXT:    [[RET:%.*]] = musttail call ptr @strncpy(ptr [[DST:%.*]], ptr [[SRC:%.*]], i32 6)
; CHECK-NEXT:    ret ptr [[RET]]
;
  %ret = musttail call ptr @strncpy(ptr %dst, ptr %src, i32 6)
  ret ptr %ret
}


define void @test_no_incompatible_attr() {
; CHECK-LABEL: @test_no_incompatible_attr(
; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr noundef nonnull align 1 dereferenceable(6) @a, ptr noundef nonnull align 1 dereferenceable(6) @hello, i32 6, i1 false)
; CHECK-NEXT:    ret void
;

  call ptr @strncpy(ptr @a, ptr @hello, i32 6)
  ret void
}