Displaying 2 results from an estimated 2 matches for "movsx16rr8".
2009 Nov 24
2
[LLVMdev] Need Advice on AVX
Ok, I am tracking down some bugs in our AVX stuff and came upon
an interesting conundrum.
The MOVQ instruction (MOVPQIto64rr in X86Instr64bit.td) only takes
xmm registers. There is no ymm version since the xxm's are subregisters.
I need to be able to match a vector element extract of element 0 on a
v4i64 vector. Obviously this is not a legal operation even with AVX
because MOVQ only
2009 Nov 24
0
[LLVMdev] Need Advice on AVX
...ay 24 November 2009 12:57, David Greene wrote:
> So I can mark it as not legal but how should it be lowered? I can't
> bitcast to a v2i64 because the vector sizes are different. I could
> do an extract_subreg and then write a pattern to match that to MOVQ.
What does this mean?
def MOVSX16rr8 : I<0xBE, MRMSrcReg, (outs GR16:$dst), (ins GR8 :$src),
"movs{bl|x}\t{$src, ${dst:subreg32}|${dst:subreg32},
$src}",
[(set GR16:$dst, (sext GR8:$src))]>, TB;
How does ${dst:subreg32} work? Can one do the same for sources? I
don't see an...