Thanks for pointing me to Eikansh's earlier patch and the SME issue. Would delaying the canonicalization until after inlining be an acceptable way to handle it? This keeps the target builtins visible while AArch64 IPA records their PSTATE.SM requirements, after which they can be converted to IFN_AVG_FLOOR or IFN_AVG_CEIL
The attached v2 retains both the signed and unsigned canonicalizations and implements that approach. I also added a focused SME regression test for the unsigned rounding-add path. Tested with an aarch64-linux-gnu cross compiler. The targeted PR tests, the new SME test, and the existing arm_neon_1.c, arm_neon_2.c, and arm_neon_3.c tests pass. Thanks Odysseas ________________________________ From: Andrea Pinski <[email protected]> Sent: 15 August 2026 02:52 To: Odysseas Georgoudis <[email protected]> Cc: [email protected] <[email protected]> Subject: Re: [PATCH] aarch64: Canonicalize halving-add builtins [PR122715] On Fri, Aug 14, 2026 at 5:33 PM Odysseas Georgoudis <[email protected]> wrote: > > The first two patches for PR122715 have been committed. This patch > handles the remaining AArch64 case. > > Advanced SIMD halving-add intrinsics remain target builtins in GIMPLE, > preventing generic average simplifications from seeing them. Canonicalize > SHADD and UHADD to IFN_AVG_FLOOR, and SRHADD and URHADD to > IFN_AVG_CEIL. > > This allows equal operands to be folded by the existing match.pd rule > while retaining optab-based instruction selection for other operands. > > Tested with an aarch64-linux-gnu cross compiler. The targeted tests > pass. This does not fully work. In fact is is the same as Eikansh's patch (except adding the signed ones): https://inbox.sourceware.org/gcc-patches/[email protected]/ The reason why it does not work is mentioned here: https://inbox.sourceware.org/gcc-patches/CALvbMcAPZu5dupGfA=3gts8avmzzpscymy8srrrqxtqhakh...@mail.gmail.com/ Basically gcc.target/aarch64/sme/arm_neon_1.c is no longer rejected when it should be. Eikansh was still looking into how to fix the issue mentioned but has not yet come up with a patch. He has been busy working on other things. If you want to look into how to resolve that issue that would be nice. Note the compile farm has a few aarch64 machines which you can use to do a bootstrap test. See https://gcc.gnu.org/wiki/CompileFarm on how to sign up (this is seperate from GCC but is used by many GCC developers and had been associated with GCC development for a long time now). Thanks, Andrea > > Thanks, > Odysseas >
PR122715-aarch64-v2.patch
Description: PR122715-aarch64-v2.patch
