diff options
Diffstat (limited to 'llvm/test/CodeGen/X86/mempcpy_ret_val.ll')
| -rw-r--r-- | llvm/test/CodeGen/X86/mempcpy_ret_val.ll | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/llvm/test/CodeGen/X86/mempcpy_ret_val.ll b/llvm/test/CodeGen/X86/mempcpy_ret_val.ll new file mode 100644 index 00000000000..d914f15101b --- /dev/null +++ b/llvm/test/CodeGen/X86/mempcpy_ret_val.ll @@ -0,0 +1,28 @@ +; RUN: llc < %s -O2 | FileCheck %s + +@G = common global i8* null, align 8 + +; This test checks that: +; (1) mempcpy is lowered as memcpy, and +; (2) its return value is DST+N i.e. the dst pointer adjusted by the copy size. +; To keep the testing of (2) independent of the exact instructions used to +; adjust the dst pointer, DST+N is explicitly computed and stored to a global +; variable G before the mempcpy call. This instance of DST+N causes the repeat +; DST+N done in the context of the return value of mempcpy to be redundant, and +; the first instance to be reused as the return value. This allows the check for +; (2) to be expressed as verifying that the MOV to store DST+N to G and +; the MOV to copy DST+N to %rax use the same source register. + +; CHECK-LABEL: RET_MEMPCPY: +; CHECK: movq [[REG:%r[a-z0-9]+]], {{.*}}G +; CHECK: callq memcpy +; CHECK: movq [[REG]], %rax +; +define i8* @RET_MEMPCPY(i8* %DST, i8* %SRC, i64 %N) { + %add.ptr = getelementptr inbounds i8, i8* %DST, i64 %N + store i8* %add.ptr, i8** @G, align 8 + %call = tail call i8* @mempcpy(i8* %DST, i8* %SRC, i64 %N) + ret i8* %call +} + +declare i8* @mempcpy(i8*, i8*, i64) |
