On 12/18/24 7:39 PM, Alexandre Oliva wrote:
A gimple block with __builtin_unreachable () can't have code after it,
and gimple optimizers ensure there isn't any, even without
optimization. But if the block requires stack adjustments,
e.g. because of a call that passes arguments on the stack, expand will
emit that after the barrier, and then rtl checkers rightfully
complain. Arrange to discard adjustments after a barrier.
Strub expanders seem to be necessary to bring about the exact
conditions that require stack adjustments after the block that ends
with a __builtin_unreachable call.
Regstrapped on x86_64-linux-gnu. Ok to install?
for gcc/ChangeLog
PR middle-end/118006
* cfgexpand.cc (expand_gimple_basic_block): Do not emit
pending stack adjustments after a barrier.
for gcc/testsuite/ChangeLog
PR middle-end/118006
* gcc.target/i386/strub-pr118006.c: New.
I don't see a cleaner way given how our pending stack adjustment code works.
OK for the trunk.
jeff
