On Tue, 9 Sep 2025, Alex Coplan wrote: > Hi, > > In this PR we have a reduction of a vector constructor, where the > type of the constructor is int16x8_t and the elements are int16x4_t; > i.e. it is representing a concatenation of two vectors. > > This triggers a match.pd pattern which looks like it was written to > handle reductions of vector constructors where the elements of the ctor > are scalars, not vectors. There is no type check to enforce this > property, which leads to the pattern replacing a reduction to scalar > with an int16x4_t vector in this case, which of course is a type error, > leading to an invalid GIMPLE ICE. > > This patch adds a type check to the pattern, only going ahead with the > transformation if the element type of the ctor matches that of the > reduction. > > Bootstrapped/regtested on aarch64-linux-gnu and x86_64-linux-gnu.
OK for trunk and branches. Richard. > OK for trunk? What about backports? The offending match.pd pattern was > introduced in r12-7326-g2ef0e75d0bbc80 but the ICE can only be > reproduced with the given testcase starting with > r13-1836-g8a1e05b7618fed (when we started lowering vcombine to GIMPLE in > the aarch64 backend). Not sure how easy it would be to construct a > generic testcase since AFAIK we don't expose a general vector concat > operation on GCC vectors. So I suppose we can either backport to 13 and > stop there or backport to 12 without a testcase (assuming a suitable one > can't be crafted). > > Thanks, > Alex > > gcc/ChangeLog: > > PR tree-optimization/121772 > * match.pd: Add type check to reduc(ctor) pattern. > > gcc/testsuite/ChangeLog: > > PR tree-optimization/121772 > * gcc.target/aarch64/torture/pr121772.c: New test. > -- Richard Biener <rguent...@suse.de> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, Germany; GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
