https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97009
--- Comment #12 from CVS Commits ---
The releases/gcc-9 branch has been updated by Martin Jambor
:
https://gcc.gnu.org/g:3181f66afc7926950115d9802de1516fba3822a2
commit r9-9326-g3181f66afc7926950115d9802de1516fba3822a2
Author: Martin Jambor
Date: Thu Apr 8 18:57:48 2021 +0200
sra: Fix bug in grp_write propagation (PR 97009)
SRA represents parts of aggregates which are arrays accessed with
unknown index as "unscalarizable regions." When there are two such
regions one within another and the outer is only read whereas the
inner is written to, SRA fails to propagate that write information
across assignments. This means that a second aggregate can contain
data while SRA thinks it does not and the pass can wrongly eliminate
big chunks of assignment from that second aggregate into a third
aggregate, which is what happens in PR 97009.
Fixed by checking all children of unscalariable accesses for the
grp_write flag.
gcc/ChangeLog:
2021-03-31 Martin Jambor
PR tree-optimization/97009
* tree-sra.c (access_or_its_child_written): New function.
(propagate_subaccesses_from_rhs): Use it instead of a simple
grp_write
test.
gcc/testsuite/ChangeLog:
2021-03-31 Martin Jambor
PR tree-optimization/97009
* gcc.dg/tree-ssa/pr97009.c: New test.
(cherry picked from commit 19d71674616e6494a60432a2a28adcd762a6c877)
