https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104497
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:3f10e0d50b5e3b3f64bc9a1a29177518d5f4468d commit r12-7222-g3f10e0d50b5e3b3f64bc9a1a29177518d5f4468d Author: Richard Biener <rguent...@suse.de> Date: Fri Feb 11 11:08:57 2022 +0100 middle-end/104497 - gimplification of vector indexing The following attempts to address gimplification of ... = VIEW_CONVERT_EXPR<int[4]>((i & 1) != 0 ? inv : src)[i]; which is problematic since gimplifying the base object ? inv : src produces a register temporary but GIMPLE does not really support a register as a base for an ARRAY_REF (even though that's not strictly validated it seems as can be seen at -O0). Interestingly the C++ frontend avoids this issue by emitting the following GENERIC instead: ... = (i & 1) != 0 ? VIEW_CONVERT_EXPR<int[4]>(inv)[i] : VIEW_CONVERT_EXPR<int[4]>(src)[i]; The proposed patch below fixes things up when using an rvalue as the base is OK by emitting a copy from a register base to a non-register one. The ?: as lvalue extension seems to be gone for C, C++ again unwraps the COND_EXPR in that case. 2022-02-11 Richard Biener <rguent...@suse.de> PR middle-end/104497 * gimplify.cc (gimplify_compound_lval): Make sure the base is a non-register if needed and possible. * c-c++-common/torture/pr104497.c: New testcase.
