[LLVMdev] Can't use SSE4.2 instructions

Cameron McInally cameron.mcinally at nyu.edu
Fri May 3 08:01:17 PDT 2013


On Fri, May 3, 2013 at 10:50 AM, Blind Faith <person.of.book at gmail.com>wrote:

> Hi,
> I'm trying to use the SSE4.2's instruction  _mm_crc32_u64 and also
> added -msse4.2 flag in the makefile, but yet I get this error when I try to
> compile my code with clang/llvm.
> LLVM ERROR: Cannot select: intrinsic %llvm.x86.sse42.crc32.64.64
> I also tried to pass -march=native, but still no luck.

The best attack would be to debug ISel.

If you would send the DAG you are trying to match, that may help too. You
may be passing operands of the wrong type to the intrinsic. Or, some other
issue may be preventing the selection.

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