2011/12/13 Vladimir Makarov <vmaka...@redhat.com>: > The following patch solves PR 21617 which is described on > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21617. > > Just adding number of necessary hard registers solves the problem but > creates 2% SPEC2000 perlbmk degradation on x86. Fortunately, removing > allocno class comparison removes the degradation. The allocno class > comparison was originally added for debugging purposes to put coloring of > allocnos of the same class in one place. It was ok when we had cover > classes which did not intersect. Now allocno classes intersect and this > comparison should be not used (at least as highest priority heuristic). > > Beside solving the problem, the patch improves a bit SPEC2000 performance > and code size on x86. > > The patch was successfully bootstrapped on x86/x86-64. I expect it should > be pretty safe for other targets because it changes heuristics only. > > Committed as rev. 182263. > > > 2011-12-12 Vladimir Makarov <vmaka...@redhat.com> > > PR rtl-optimization/21617 > * ira-color.c (bucket_allocno_compare_func): Don't compare > allocno classes. Compare number of hard registers needed. >
Hello, Vladimir, I think there may be a typo in this patch. I saw few degradations in EEMBC2.0 benchmarks caused by this patch. Following fix removes these degradations: - if ((diff = (ira_reg_class_max_nregs[cl1][ALLOCNO_MODE (a1)] - - ira_reg_class_max_nregs[cl2][ALLOCNO_MODE (a2)])) != 0) + if ((diff = (ira_reg_class_max_nregs[cl2][ALLOCNO_MODE (a2)] + - ira_reg_class_max_nregs[cl1][ALLOCNO_MODE (a1)])) != 0) I suspect typo because previous calculation of 'diff' value used f(a2) - f(a1) formula and now it is f(a1) - f(a2). Could you please look at it? Thanks, Ilya
