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...