https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113421
--- Comment #2 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:9f8ba332e988fb582f6ca32465f6d65283f53b3a commit r14-8186-g9f8ba332e988fb582f6ca32465f6d65283f53b3a Author: Jakub Jelinek <ja...@redhat.com> Date: Wed Jan 17 14:43:40 2024 +0100 lower-bitint: Avoid overlap between destinations and sources in libgcc calls [PR113421] The following testcase is miscompiled because the bitint lowering emits a .MULBITINT (&a, 1024, &a, 1024, &x, 1024); call. The bug is in the overlap between the destination and source, that is something the libgcc routines don't handle, they use the source arrays during the entire algorithms which computes the destination array(s). For the mapping of SSA_NAMEs to VAR_DECLs the code already supports that correctly, but the checking whether a load from memory can be used directly without a temporary even when earlier we decided to merge the multiplication/division/modulo etc. with a store didn't. The following patch implements that. 2024-01-17 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/113421 * gimple-lower-bitint.cc (stmt_needs_operand_addr): Adjust function comment. (bitint_dom_walker::before_dom_children): Add g temporary to simplify formatting. Start at vop rather than cvop even if stmt is a store and needs_operand_addr. * gcc.dg/torture/bitint-50.c: New test.
