https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97971
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-9 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:2f9a241a308c32108b922bd768b7576c5c34e440 commit r9-9414-g2f9a241a308c32108b922bd768b7576c5c34e440 Author: Jakub Jelinek <ja...@redhat.com> Date: Wed Feb 3 09:07:36 2021 +0100 lra-constraints: Fix error-recovery for bad inline-asms [PR97971] The following testcase has ice-on-invalid, it can't be reloaded, but we shouldn't ICE the compiler because the user typed non-sense. In current_insn_transform we have: if (process_alt_operands (reused_alternative_num)) alt_p = true; if (check_only_p) return ! alt_p || best_losers != 0; /* If insn is commutative (it's safe to exchange a certain pair of operands) then we need to try each alternative twice, the second time matching those two operands as if we had exchanged them. To do this, really exchange them in operands. If we have just tried the alternatives the second time, return operands to normal and drop through. */ if (reused_alternative_num < 0 && commutative >= 0) { curr_swapped = !curr_swapped; if (curr_swapped) { swap_operands (commutative); goto try_swapped; } else swap_operands (commutative); } if (! alt_p && ! sec_mem_p) { /* No alternative works with reloads?? */ if (INSN_CODE (curr_insn) >= 0) fatal_insn ("unable to generate reloads for:", curr_insn); error_for_asm (curr_insn, "inconsistent operand constraints in an %<asm%>"); lra_asm_error_p = true; ... and so handle inline asms there differently (and delete/nullify them after this) - fatal_insn is only called for non-inline asm. But in process_alt_operands we do: /* Both the earlyclobber operand and conflicting operand cannot both be user defined hard registers. */ if (HARD_REGISTER_P (operand_reg[i]) && REG_USERVAR_P (operand_reg[i]) && operand_reg[j] != NULL_RTX && HARD_REGISTER_P (operand_reg[j]) && REG_USERVAR_P (operand_reg[j])) fatal_insn ("unable to generate reloads for " "impossible constraints:", curr_insn); and thus ICE even for inline-asms. I think it is inappropriate to delete/nullify the insn in process_alt_operands, as it could be done e.g. in the check_only_p mode, so this patch just returns false in that case, which results in the caller have alt_p false, and as inline asm isn't simple move, sec_mem_p will be also false (and it isn't commutative either), so for check_only_p it will suggests to the callers it isn't ok and otherwise will emit error and delete/nullify the inline asm insn. 2021-02-03 Jakub Jelinek <ja...@redhat.com> PR middle-end/97971 * lra-constraints.c (process_alt_operands): For inline asm, don't call fatal_insn, but instead return false. * gcc.target/i386/pr97971.c: New test. (cherry picked from commit 4dd7141653b57f638fc32291245d57d4dcfa3813)
