https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91189
Bug ID: 91189
Summary: 20% binary size regression in avr-gcc 9.1.0 from 8.3.0
Product: gcc
Version: 9.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: larsch at belunktum dot dk
Target Milestone: ---
There seem to be a severe ~20% code size regression on AVR target (atmega328p)
in gcc 9.1.0.
I'm building https://github.com/gnea/grbl, which need to fit in 32k. This used
to work just fine (29786 bytes), but with 9.1.0 it is way over target size
(35492 bytes).
Compile options are the default '-Os -flto' on both.
gcc 8.3.0
% avr-gcc --version
avr-gcc (GCC) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
% avr-size grbl.hex
text data bss dec hex filename
0 29786 0 29786 745a grbl.hex
gcc 9.1.0:
% avr-gcc --version
avr-gcc (GCC) 9.1.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
% avr-size grbl.hex
text data bss dec hex filename
0 35492 0 35492 8aa4 grbl.hex
