https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106101
--- Comment #26 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Andreas Krebbel <kreb...@gcc.gnu.org>: https://gcc.gnu.org/g:e1357577e6e39430869e294f94c2c547717b960f commit r12-9058-ge1357577e6e39430869e294f94c2c547717b960f Author: Andreas Krebbel <kreb...@linux.ibm.com> Date: Mon Jan 23 08:56:05 2023 +0100 PR 106101: IBM zSystems: Fix strict_low_part problem This avoids generating illegal (strict_low_part (reg ...)) RTXs. This required two changes: 1. Do not use gen_lowpart to generate the inner expression of a STRICT_LOW_PART. gen_lowpart might fold the SUBREG either because there is already a paradoxical subreg or because it can directly be applied to the register. A new wrapper function makes sure that we always end up having an actual SUBREG. 2. Change the movstrict patterns to enforce a SUBREG as inner operand of the STRICT_LOW_PARTs. The new predicate introduced for the destination operand requires a SUBREG expression with a register_operand as inner operand. However, since reload strips away the majority of the SUBREGs we have to accept single registers as well once we reach reload. Bootstrapped and regression tested on IBM zSystems 64 bit. gcc/ChangeLog: PR target/106101 * config/s390/predicates.md (subreg_register_operand): New predicate. * config/s390/s390-protos.h (s390_gen_lowpart_subreg): New function prototype. * config/s390/s390.cc (s390_gen_lowpart_subreg): New function. (s390_expand_insv): Use s390_gen_lowpart_subreg instead of gen_lowpart. * config/s390/s390.md ("*get_tp_64", "*zero_extendhisi2_31") ("*zero_extendqisi2_31", "*zero_extendqihi2_31"): Likewise. ("movstrictqi", "movstricthi", "movstrictsi"): Use the subreg_register_operand predicate instead of register_operand. gcc/testsuite/ChangeLog: PR target/106101 * gcc.c-torture/compile/pr106101.c: New test. (cherry picked from commit 585a21bab3ec688c2039bff2922cc372d8558283)
