; 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 writable 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 writable 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 }