reames added a comment.
I'm not fluent on strict FP, so let me summarize my understanding. This is
mostly so you can easily correct me if one my assumptions is wrong.
- Under strict FP, clang will emit constrained fp intrinsics instead of normal
floating point ops.
- To my knowledge, clang will never emit an explicit vector constrained
intrinsic.
- The vectorizers (LV, SLP) don't appear to have any handling for constrained
FP intrinsics. If it did, I'd expect it to have to ask about legality of the
widened operation - the same way it does for e.g. a scatter/gather.
So, my question is: why don't we support StrictFP when targeting a vector
enabled platform? Don't we trivially support them by simply never using the
vector forms?
================
Comment at: clang/lib/Basic/Targets/RISCV.cpp:286
+ // StrictFP support for vectors is incomplete.
+ if (ISAInfo->hasExtension("zve32x"))
+ HasStrictFP = false;
----------------
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.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D130311/new/
https://reviews.llvm.org/D130311
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