http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53595
Bug #: 53595
Summary: Code size increase of +10% between two 4.7.1 snapshot
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: g...@gcc.gnu.org
Created attachment 27568
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27568
C source
This problem report is about a +10% of code size increase between the following
two 4.7.1 versions of gcc:
V1: SVN 185693 gcc-4_7-branch from 2012-03-22, 4.7.1 (prerelease)
V2: SVN 188257 gcc-4_7-branch from 2012-06-06, 4.7.1 (prerelease)
The attached test case is a reduced test case out of many other sources that
suffer from the same problem, so that the overall performance degradation is
unpleasant.
The RTL dumps show that the first pass that differs is IRA.
== Command line ==
$ avr-gcc -mmcu=atmega168 -c -std=gnu99 -Os -mstrict-X -ffixed-2 -ffixed-3 -dp
-fdump-rtl-ira-details -fdump-rtl-reload-details -fdump-rtl-postreload-details
bresenham-i.c -o bresenham-i-1.o -save-temps=obj
resp. with -o bresenham-i-2.o for the second 4.7.1 snapshot.
== GCC configure ==
Target: avr
Configured with: ../../gcc.gnu.org/gcc-4_7-branch/configure --target=avr
--prefix=/local/gnu/install/gcc-4.7-mingw32 --host=i386-mingw32
--build=i686-linux-gnu --enable-languages=c,c++ --disable-nls --disable-shared
--with-dwarf2
Thread model: single
gcc version 4.7.1 20120606 (prerelease) (GCC)
GNU C (GCC) version 4.7.1 20120606 (prerelease) (avr)
compiled by GNU C version 3.4.5 (mingw-vista special r2), GMP version
4.3.2, MPFR version 2.4.2, MPC version 0.8.2
It's a canadian cross, but that surely does not matter here...
