[PATCH] D111790: [AArch64][Driver][SVE] Allow -msve-vector-bits=<n>+ syntax to mean no maximum vscale

[Bradley Smith via Phabricator via cfe-commits]

bsmith added inline comments.


================
Comment at: clang/lib/Sema/SemaType.cpp:7916
   // The attribute vector size must match -msve-vector-bits.
-  if (VecSize != S.getLangOpts().ArmSveVectorBits) {
+  if (VecSize != S.getLangOpts().VScaleMin * 128) {
     S.Diag(Attr.getLoc(), diag::err_attribute_bad_sve_vector_size)
----------------
bsmith wrote:
> paulwalker-arm wrote:
> > I'm thinking there should be a check for `S.getLangOpts().VScaleMin == S.getLangOpts().VScaleMax` somewhere, but I guess the current diagnostic probably doesn't account for two values, nor should it really.  What about just duplicating this block but using `VScaleMax` in place of `VScaleMin`?
> I think I would rather have a separate check for min == max, and output a diagnostic stating that an exact -msve-vector-bits value must be used, does that sound sensible?
> 
> This could then perhaps be combined with the previous comment to produce sensible output, i.e.:
> 
> !vscale_min -> not supported
> vscale_min != vscale_max -> must be fixed value
Actually, now that I re-read the error message, and the fact that is directly refers to the valid values, I think instead there should just be an initial check of `min == 0 || min != max`.


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D111790/new/

https://reviews.llvm.org/D111790