https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97971
--- Comment #7 from CVS Commits ---
The releases/gcc-9 branch has been updated by Jakub Jelinek
:
https://gcc.gnu.org/g:2f9a241a308c32108b922bd768b7576c5c34e440
commit r9-9414-g2f9a241a308c32108b922bd768b7576c5c34e440
Author: Jakub Jelinek
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 %");
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
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)
