[PATCH] D108039: [AArch64][SME] Support NEON scalar FP instructions in streaming mode

[Cullen Rhodes via Phabricator via llvm-commits]

c-rhodes added inline comments.


================
Comment at: llvm/lib/Target/AArch64/AArch64InstrFormats.td:6834
   let mayLoad = 0, mayStore = 0, hasSideEffects = 0 in {
+    // FABD is illegal in streaming mode. FMULX/FRECPS/FRSQRTS are legal.
+    let Predicates = !if(!ne(opc, 0b010), [HasNEONorStreamingSVE],
----------------
c-rhodes wrote:
> david-arm wrote:
> > Hi @c-rhodes, I think this might look nicer if we just put predicates around the instructions that derive from these classes instead, i.e.
> > 
> >   let Predicate = [HasNEON] in {
> >     defm FABD     : SIMDFPThreeScalar<1, 1, 0b010, "fabd", int_aarch64_sisd_fabd>;
> >   }
> > 
> >   let Predicates = [HasNEONorStreamingSVE] in {
> >     defm FMULX    : SIMDFPThreeScalar<0, 0, 0b011, "fmulx", int_aarch64_neon_fmulx>;
> >     defm FRECPS   : SIMDFPThreeScalar<0, 0, 0b111, "frecps", int_aarch64_neon_frecps>;
> >     defm FRSQRTS  : SIMDFPThreeScalar<0, 1, 0b111, "frsqrts", int_aarch64_neon_frsqrts>;
> >   }
> > 
> > Hi @c-rhodes, I think this might look nicer if we just put predicates around the instructions that derive from these classes instead, i.e.
> > 
> >   let Predicate = [HasNEON] in {
> >     defm FABD     : SIMDFPThreeScalar<1, 1, 0b010, "fabd", int_aarch64_sisd_fabd>;
> >   }
> > 
> >   let Predicates = [HasNEONorStreamingSVE] in {
> >     defm FMULX    : SIMDFPThreeScalar<0, 0, 0b011, "fmulx", int_aarch64_neon_fmulx>;
> >     defm FRECPS   : SIMDFPThreeScalar<0, 0, 0b111, "frecps", int_aarch64_neon_frecps>;
> >     defm FRSQRTS  : SIMDFPThreeScalar<0, 1, 0b111, "frsqrts", int_aarch64_neon_frsqrts>;
> >   }
> > 
> 
> that would break the fp16 variant which requires `+fullfp16`
> > Hi @c-rhodes, I think this might look nicer if we just put predicates around the instructions that derive from these classes instead, i.e.
> > 
> >   let Predicate = [HasNEON] in {
> >     defm FABD     : SIMDFPThreeScalar<1, 1, 0b010, "fabd", int_aarch64_sisd_fabd>;
> >   }
> > 
> >   let Predicates = [HasNEONorStreamingSVE] in {
> >     defm FMULX    : SIMDFPThreeScalar<0, 0, 0b011, "fmulx", int_aarch64_neon_fmulx>;
> >     defm FRECPS   : SIMDFPThreeScalar<0, 0, 0b111, "frecps", int_aarch64_neon_frecps>;
> >     defm FRSQRTS  : SIMDFPThreeScalar<0, 1, 0b111, "frsqrts", int_aarch64_neon_frsqrts>;
> >   }
> > 
> 
> that would break the fp16 variant which requires `+fullfp16`

I've changed it to pass the predicate as an argument, hopefully that makes it clearer


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D108039/new/

https://reviews.llvm.org/D108039