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1; RUN: llc < %s -mtriple=x86_64-unknown-linux -O2 | FileCheck %s2 3; This test checks that:4; (1) mempcpy is lowered as memcpy, and 5; (2) its return value is DST+N i.e. the dst pointer adjusted by the copy size.6; To keep the testing of (2) independent of the exact instructions used to7; adjust the dst pointer, DST+N is explicitly computed and stored to a global8; variable G before the mempcpy call. This instance of DST+N causes the repeat9; DST+N done in the context of the return value of mempcpy to be redundant, and10; the first instance to be reused as the return value. This allows the check for11; (2) to be expressed as verifying that the MOV to store DST+N to G and12; the MOV to copy DST+N to %rax use the same source register.13 14; Also see mempcpy-32.ll15 16@G = common dso_local global ptr null, align 817 18; CHECK-LABEL: RET_MEMPCPY:19; CHECK: movq [[REG:%r[a-z0-9]+]], {{.*}}G20; CHECK: callq {{.*}}memcpy21; CHECK: movq [[REG]], %rax22;23define dso_local ptr @RET_MEMPCPY(ptr %DST, ptr %SRC, i64 %N) {24 %add.ptr = getelementptr inbounds i8, ptr %DST, i64 %N25 store ptr %add.ptr, ptr @G, align 826 %call = tail call ptr @mempcpy(ptr %DST, ptr %SRC, i64 %N) 27 ret ptr %call28}29 30declare ptr @mempcpy(ptr, ptr, i64)31