1 ; RUN: llc < %s -mtriple=x86_64-unknown-linux -O2 | FileCheck %s 2 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 to 7 ; adjust the dst pointer, DST+N is explicitly computed and stored to a global 8 ; variable G before the mempcpy call. This instance of DST+N causes the repeat 9 ; DST+N done in the context of the return value of mempcpy to be redundant, and 10 ; the first instance to be reused as the return value. This allows the check for 11 ; (2) to be expressed as verifying that the MOV to store DST+N to G and 12 ; the MOV to copy DST+N to %rax use the same source register. 13 14 ; Also see mempcpy-32.ll 15 16 @G = common global i8* null, align 8 17 18 ; CHECK-LABEL: RET_MEMPCPY: 19 ; CHECK: movq [[REG:%r[a-z0-9]+]], {{.*}}G 20 ; CHECK: callq {{.*}}memcpy 21 ; CHECK: movq [[REG]], %rax 22 ; 23 define i8* @RET_MEMPCPY(i8* %DST, i8* %SRC, i64 %N) { 24 %add.ptr = getelementptr inbounds i8, i8* %DST, i64 %N 25 store i8* %add.ptr, i8** @G, align 8 26 %call = tail call i8* @mempcpy(i8* %DST, i8* %SRC, i64 %N) 27 ret i8* %call 28 } 29 30 declare i8* @mempcpy(i8*, i8*, i64) 31
