https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114936
--- Comment #1 from GCC Commits ---
The master branch has been updated by Alex Coplan :
https://gcc.gnu.org/g:73c8e24b692e691c665d0f1f5424432837bd8c06
commit r15-320-g73c8e24b692e691c665d0f1f5424432837bd8c06
Author: Alex Coplan
Date: Fri May 3 14:12:32 2024 +
aarch64: Fix typo in aarch64-ldp-fusion.cc:combine_reg_notes [PR114936]
This fixes a typo in combine_reg_notes in the load/store pair fusion
pass. As it stands, the calls to filter_notes store any
REG_FRAME_RELATED_EXPR to fr_expr with the following association:
- i2 -> fr_expr[0]
- i1 -> fr_expr[1]
but then the checks inside the following if statement expect the
opposite (more natural) association, i.e.:
- i2 -> fr_expr[1]
- i1 -> fr_expr[0]
this patch fixes the oversight by swapping the fr_expr indices in the
calls to filter_notes.
In hindsight it would probably have been less confusing / error-prone to
have combine_reg_notes take an array of two insns, then we wouldn't have
to mix 1-based and 0-based indexing as well as remembering to call
filter_notes in reverse program order. This however is a minimal fix
for backporting purposes.
gcc/ChangeLog:
PR target/114936
* config/aarch64/aarch64-ldp-fusion.cc (combine_reg_notes):
Ensure insn iN has its REG_FRAME_RELATED_EXPR (if any) stored in
FR_EXPR[N-1], thus matching the correspondence expected by the
copy_rtx calls.
