https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104839
--- Comment #6 from CVS 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:7ca24ae5701769fccabf8cca4cad6987cb2187c6 commit r12-7556-g7ca24ae5701769fccabf8cca4cad6987cb2187c6 Author: Jakub Jelinek <ja...@redhat.com> Date: Wed Mar 9 09:12:38 2022 +0100 simplify-rtx: Fix up SUBREG_PROMOTED_SET arguments [PR104839] The following testcase is miscompiled on powerpc64le-linux at -O1 and higher (except for -Og). The bug was introduced in r12-3252-gcad36f38576a6a7 which for SIGN_EXTEND from SUBREG_PROMOTED_SIGNED_P SUBREG used SUBREG_PROMOTED_SET (temp, 1) (but that makes temp SUBREG_PROMOTED_UNSIGNED_P because SRP_UNSIGNED is 1) and similarly the ZERO_EXTEND from SUBREG_PROMOTED_UNSIGNED_P SUBREG used SUBREG_PROMOTED_SET (temp, 0) (but that makes temp SUBREG_PROMOTED_SIGNED_P because SRP_SIGNED is 0). The following patch fixes that (swaps the 0s and 1s), but for better readability uses the SRP_* constants. rtl.h has: /* Valid for subregs which are SUBREG_PROMOTED_VAR_P(). In that case this gives the necessary extensions: 0 - signed (SPR_SIGNED) 1 - normal unsigned (SPR_UNSIGNED) 2 - value is both sign and unsign extended for mode (SPR_SIGNED_AND_UNSIGNED). -1 - pointer unsigned, which most often can be handled like unsigned extension, except for generating instructions where we need to emit special code (ptr_extend insns) on some architectures (SPR_POINTER). */ The expr.c change in the same commit looks ok to me (passes unsignedp to SUBREG_PROMOTED_SET, so 0 for signed, 1 for unsigned). 2022-03-09 Jakub Jelinek <ja...@redhat.com> PR rtl-optimization/104839 * simplify-rtx.cc (simplify_unary_operation_1) <case SIGN_EXTEND>: Use SRP_SIGNED instead of incorrect 1 in SUBREG_PROMOTED_SET. (simplify_unary_operation_1) <case ZERO_EXTEND>: Use SRP_UNSIGNED instead of incorrect 0 in SUBREG_PROMOTED_SET. * gcc.c-torture/execute/pr104839.c: New test.
