craig.topper added inline comments.
================
Comment at: clang/lib/Basic/Targets/RISCV.cpp:286
+ // StrictFP support for vectors is incomplete.
+ if (ISAInfo->hasExtension("zve32x"))
+ HasStrictFP = false;
----------------
reames wrote:
> craig.topper wrote:
> > reames wrote:
> > > asb wrote:
> > > > There's also code in RISCVISAInfo.cpp that does `HasVector =
> > > > Exts.count("zve32x") != 0`. It's probably worth adding a helper
> > > > (`hasVInstructions`?) that encapsulates this, and use it from both
> > > > places.
> > > It's not clear to me why this condition is specific to embedded vector
> > > variants. Do we have strict FP with +V? Either you need to fix a
> > > comment here, or the condition. One or the other.
> > V implies Zve64d implies Zve64f implies Zve32f and Zve64x. Zve32f implies
> > Zve32x. Zve32x is the root of the vector inheritance tree.
> So, I went digging. I agree that our *implementation* treats V as implying
> Zve64d, but I can find anything in the *specification* to that effect. The
> feature set seems like it might be identical between the two, but I don't see
> anything in the spec which requires a +V implementation to claim support for
> Zve64d. Do you have particular wording in mind I'm missing?
>
> (Regardless, the fact we assume this elsewhere means this is a non-blocking
> comment for this review. At the very least, this isn't introducing a new
> problem.)
We removed the implication for a brief period but Krste and Andrew disagreed. I
believe this is now covered by the note at the end of
https://github.com/riscv/riscv-v-spec/blob/master/v-spec.adoc#183-v-vector-extension-for-application-processors
"As is the case with other RISC-V extensions, it is valid to include
overlapping extensions in the same ISA string. For example, RV64GCV and
RV64GCV_Zve64f are both valid and equivalent ISA strings, as is
RV64GCV_Zve64f_Zve32x_Zvl128b."
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D130311/new/
https://reviews.llvm.org/D130311
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
