https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93044
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Andrew Pinski <pins...@gcc.gnu.org>: https://gcc.gnu.org/g:cc2003cd87532f319c94028f17d20a327df5ccfa commit r14-2890-gcc2003cd87532f319c94028f17d20a327df5ccfa Author: Andrew Pinski <apin...@marvell.com> Date: Sun Jul 23 21:44:39 2023 +0000 Fix PR 93044: extra cast is not removed In this case we are not removing convert to a bigger size back to the same size (or smaller) if signedness does not match. For an example: ``` signed char _1; ... _1 = *a_4(D); b_5 = (short unsigned int) _1; _2 = (unsigned char) b_5; ``` The inner cast is not needed and can be removed but was not. The match pattern for removing the extra cast is overly complex so decided to add a new case for rather than trying to modify the current if statement here. Committed as approved. Bootstrapped and tested on x86_64-linux-gnu with no regressions. gcc/ChangeLog: PR tree-optimization/93044 * match.pd (nested int casts): A truncation (to the same size or smaller) can always remove the inner cast. gcc/testsuite/ChangeLog: PR tree-optimization/93044 * gcc.dg/tree-ssa/cast-1.c: New test. * gcc.dg/tree-ssa/cast-2.c: New test.
