1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
|
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -S -passes=memcpyopt -verify-memoryssa | FileCheck %s
target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
declare void @llvm.memcpy.p0.p0.i64(ptr nocapture, ptr nocapture readonly, i64, i1) unnamed_addr nounwind
declare void @llvm.memset.p0.i64(ptr nocapture, i8, i64, i1) nounwind
; all bytes of %dst that are touch by the memset are dereferenceable
define void @must_remove_memcpy(ptr noalias nocapture dereferenceable(4096) %dst) nofree nosync {
; CHECK-LABEL: @must_remove_memcpy(
; CHECK-NEXT: [[SRC:%.*]] = alloca [4096 x i8], align 1
; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr [[DST:%.*]], i8 0, i64 4096, i1 false)
; CHECK-NEXT: ret void
;
%src = alloca [4096 x i8], align 1
call void @llvm.memset.p0.i64(ptr %src, i8 0, i64 4096, i1 false)
call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %src, i64 4096, i1 false) #2
ret void
}
; memset touch more bytes than those guaranteed to be dereferenceable
; We can't remove the memcpy, but we can turn it into an independent memset.
define void @must_not_remove_memcpy(ptr noalias nocapture dereferenceable(1024) %dst) nofree nosync {
; CHECK-LABEL: @must_not_remove_memcpy(
; CHECK-NEXT: [[SRC:%.*]] = alloca [4096 x i8], align 1
; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr [[SRC]], i8 0, i64 4096, i1 false)
; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr [[DST:%.*]], i8 0, i64 4096, i1 false)
; CHECK-NEXT: ret void
;
%src = alloca [4096 x i8], align 1
call void @llvm.memset.p0.i64(ptr %src, i8 0, i64 4096, i1 false)
call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %src, i64 4096, i1 false) #2
ret void
}
|
