[Bug tree-optimization/126376] aarch64: cunrolli unrolls small constant-trip inner loops and blocks dot-product vectorization

"konstantinos.eleftheriou at vrull dot eu via Gcc-bugs" <[email protected]> Thu, 23 Jul 2026 17:05:55 +0000

Newsgroups	gmane.comp.gcc.bugs
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126376

--- Comment #4 from Konstantinos Eleftheriou <konstantinos.eleftheriou at vrull dot eu> ---
(In reply to Drea Pinski from comment #3)
> (In reply to Konstantinos Eleftheriou from comment #1)
> > We are preparing a patch for the suggested fix.
> 
> except that is just a workaround.

True. The problem is that after the unrolling we lose the reduction status.
Teaching SLP to recognize DOT_PROD patterns in straight-line code will be
a much more complicated solution with a higher regression risk.
We went with this approach as a simple, low-risk workaround for now.