https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113119
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:7590d975ecfdae4f112b5086c017101c08f07e3e commit r14-7000-g7590d975ecfdae4f112b5086c017101c08f07e3e Author: Jakub Jelinek <ja...@redhat.com> Date: Mon Jan 8 13:57:26 2024 +0100 lower-bitint: Punt .*_OVERFLOW optimization if cast from IMAGPART_EXPR appears before REALPART_EXPR [PR113119] _BitInt lowering for .{ADD,SUB,MUL}_OVERFLOW calls which have both REALPART_EXPR and IMAGPART_EXPR used and have a cast from the IMAGPART_EXPR to a boolean or normal integral type lowers them at the point of the REALPART_EXPR statement (which is especially needed if the lhs of the call is complex with large/huge _BitInt element type); we emit the stmt to set the lhs of the cast at the same spot as well. Normally, the lowering of __builtin_{add,sub,mul}_overflow arranges the REALPART_EXPR to come before IMAGPART_EXPR, followed by cast from that, but as the testcase shows, a redundant __builtin_*_overflow call and VN can reorder those and we then ICE because the def-stmt of the former cast from IMAGPART_EXPR may appear after its uses. We already check that all of REALPART_EXPR, IMAGPART_EXPR and the cast from the latter appear in the same bb as the .{ADD,SUB,MUL}_OVERFLOW call in the optimization, the following patch just extends it to make sure cast appears after REALPART_EXPR; if not, we punt on the optimization and expand it as a store of a complex _BitInt on the location of the ifn call. Only the testcase in the testsuite is changed by the patch, all other __builtin_*_overflow* calls in the bitint* tests (and there are quite a few) have REALPART_EXPR first. 2024-01-08 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/113119 * gimple-lower-bitint.cc (optimizable_arith_overflow): Punt if both REALPART_EXPR and cast from IMAGPART_EXPR appear, but cast is before REALPART_EXPR. * gcc.dg/bitint-61.c: New test.
