[PATCH] D110253: [SelectionDAG] Make WidenVecRes_EXTRACT_SUBVECTOR work for scalable vectors.

Mon Sep 27 01:55:07 PDT 2021

sdesmalen added a comment.

In D110253#3023769 <https://reviews.llvm.org/D110253#3023769>, @frasercrmck wrote:

> I'd be interested in seeing some RISCV tests to improve the coverage (but I won't block on it)

I'm happy to add a test, just wasn't entirely sure what types are legal for RVV. Would the same `extract <vscale x 6 x half> from <vscale x 12 x half>` be suitable?

================
Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp:4117
+
+    report_fatal_error("Don't know how to widen the result of "
+                       "EXTRACT_SUBVECTOR for scalable vectors");
----------------
frasercrmck wrote:
> Nit: is this message too general now? It implies we can't do anything, ever.
Ah that wasn't my intention, I meant it more as "the code as it is today doesn't know how to widen the result of extract_subvector for scalable vectors". I think the message is correct though, since LLVM doesn't know how to widen it and it avoids falling into the fixed-width code below.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110253/new/

https://reviews.llvm.org/D110253