https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110754
--- Comment #9 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:39920447f876128ff7942a9cd931021800865894 commit r14-8910-g39920447f876128ff7942a9cd931021800865894 Author: Jakub Jelinek <ja...@redhat.com> Date: Sat Feb 10 11:28:00 2024 +0100 gimple-low: Fix up handling of volatile automatic vars in assume attribute [PR110754] As the following testcases show, the gimple-low outlining of assume magic functions handled volatile automatic vars (including parameters/results) like non-volatile ones except it copied volatile to the new PARM_DECL, which has the undesirable effect that a load from the volatile var is passed to IFN_ASSUME and so there is a side-effect there even when side-effects of the assume attribute shouldn't be evaluated. The following patch fixes that by passing address of the volatile variables/parameters/results instead and doing loads or stores from it or to it where it was originally accessed in the assume attribute expression. 2024-02-10 Jakub Jelinek <ja...@redhat.com> PR middle-end/110754 * gimple-low.cc (assumption_copy_decl): For TREE_THIS_VOLATILE decls create PARM_DECL with pointer to original type, set TREE_READONLY and keep TREE_THIS_VOLATILE, TREE_ADDRESSABLE, DECL_NOT_GIMPLE_REG_P and DECL_BY_REFERENCE cleared. (adjust_assumption_stmt_op): For remapped TREE_THIS_VOLATILE decls wrap PARM_DECL into a simple TREE_THIS_NO_TRAP MEM_REF. (lower_assumption): For TREE_THIS_VOLATILE vars pass ADDR_EXPR of the var as argument. * gcc.dg/attr-assume-6.c: New test. * g++.dg/cpp23/attr-assume12.C: New test.
