[Bug tree-optimization/114074] [11/12/13 Regression] wrong code at -O1 and above on x86_64-linux-gnu since r8-343
cvs-commit at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Fri Mar 8 13:41:06 GMT 2024
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114074
--- Comment #11 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:
https://gcc.gnu.org/g:018ddc86b928514d7dfee024dcdeb204d5dcdd61
commit r14-9391-g018ddc86b928514d7dfee024dcdeb204d5dcdd61
Author: Richard Biener <rguenther@suse.de>
Date: Fri Mar 8 13:27:12 2024 +0100
tree-optimization/114269 - 434.zeusmp regression after SCEV analysis fix
The following addresses a performance regression caused by the recent
SCEV analysis fix with regard to folding multiplications and undefined
behavior on overflow. We do not handle (T) { a, +, b } * c but can
treat sign-conversions from unsigned by performing the multiplication
in the unsigned type. That's what we already do for additions (but
that misses one case that turns out important).
This fixes the 434.zeusmp regression for me.
PR tree-optimization/114269
PR tree-optimization/114074
* tree-chrec.cc (chrec_fold_plus_1): Handle sign-conversions
in the third CASE_CONVERT case as well.
(chrec_fold_multiply): Handle sign-conversions from unsigned
by performing the operation in the unsigned type.
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