[llvm-commits] [LLVM, llc] PATCH for PR11691: llc assertion failure generating arm neon vst2 with pointer update

Jim Grosbach grosbach at apple.com
Thu Jan 12 10:47:10 PST 2012


Just to close the loop on this for this list, this was resolved in http://llvm.org/bugs/show_bug.cgi?id=11691.

-Jim

On Jan 10, 2012, at 9:40 AM, Stepan Dyatkovskiy wrote:

> Ping.
> -Stepan.
> 
> 09.01.2012, 15:58, "Stepan Dyatkovskiy" <STPWORLD at narod.ru>:
>> Hi all. It seems that I found where the bug lives.
>> 
>> We want to expand VST2d16PseudoWB_fixed to VST2d8wb_fixed.
>> Look at first one:
>> %vreg1<def> = VST2d16PseudoWB_fixed %vreg1<kill>, 0, %noreg, %vreg3<undef>, pred:14, pred:%noreg; mem:ST16[%lsr.iv1](align=2) GPR:%vreg1 QPR:%vreg3
>> 
>> Op #4 is dummy here (%noreg). Looking at SelectVST method I can conclude that Op4 is added to keep format of all VST2XXXPseudoWB_XXXXX the same. What the Reg0 means here though? Looks like NULL register. If I get right it Op4 is write-back operand, but it is not used in "fixed" vst instructions.
>> 
>> So when we want to expand this instruction to VST2d8wb_fixed we should skip write-back place-holder.
>> 
>> Please find the attached patch.
>> 
>> -Stepan.
>> 
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