https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106187
--- Comment #54 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Richard Earnshaw <rearn...@gcc.gnu.org>: https://gcc.gnu.org/g:3835765ae96d294bb71dd8cb05db543d89725f7b commit r12-8738-g3835765ae96d294bb71dd8cb05db543d89725f7b Author: Richard Earnshaw <rearn...@arm.com> Date: Wed Aug 3 10:01:51 2022 +0100 cselib: add function to check if SET is redundant [PR106187] A SET operation that writes memory may have the same value as an earlier store but if the alias sets of the new and earlier store do not conflict then the set is not truly redundant. This can happen, for example, if objects of different types share a stack slot. To fix this we define a new function in cselib that first checks for equality and if that is successful then finds the earlier store in the value history and checks the alias sets. The routine is used in two places elsewhere in the compiler: cfgcleanup and postreload. gcc/ChangeLog: PR rtl-optimization/106187 * alias.h (mems_same_for_tbaa_p): Declare. * alias.cc (mems_same_for_tbaa_p): New function. * dse.cc (record_store): Use it instead of open-coding alias check. * cselib.h (cselib_redundant_set_p): Declare. * cselib.cc: Include alias.h (cselib_redundant_set_p): New function. * cfgcleanup.cc: (mark_effect): Use cselib_redundant_set_p instead of rtx_equal_for_cselib_p. * postreload.cc (reload_cse_simplify): Use cselib_redundant_set_p. (reload_cse_noop_set_p): Delete. (cherry picked from commit 64ce76d940501cb04d14a0d36752b4f93473531c)
