Hello! > This is using the Polyhedron Fortran test. > http://www.polyhedron.co.uk/MFL6VW74649
> Using several options, the gas_dyn test got much slower; however, with > some options, the performance remained roughly the same. > In terms of the geometric mean, it is a slowdown of around 1%. > The run time of the other programs only changed slightly (up/down/const). > Result from http://www.suse.de/~gcctest/c++bench/polyhedron/ > -ffast-math -funroll-loops -O3 -ftree-vectorize -march= ??? (opteron I > think). > 14.59s -> 21.06s (44% slower) > Result on for my AMD Athlon64 4800+, > http://physik.fu-berlin.de/~tburnus/gcc-trunk/benchmark/ > Yesterday: 2007-09-10-r128322 > Today: 2007-09-11-r128363 The problem was introduced by r128353 [1]: 2007-09-10 Harsha Jagasia <[EMAIL PROTECTED]> Jan Sjodin <[EMAIL PROTECTED]> * tree-vect-analyze.c (vect_analyze_operations): Change comparison of loop iterations with threshold to less than or equal to instead of less than. Reduce min_scalar_loop_bound by one. * tree-vect-transform.c (vect_estimate_min_profitable_iters): Change prologue and epilogue iterations estimate to vf/2, when unknown at compile-time. Change versioning guard cost to taken_branch_cost. If peeling for alignment is unknown at compile-time, change peel guard costs to one taken branch and one not-taken branch per peeled loop. If peeling for alignment is known but number of scalar loop iterations is unknown at compile-time, change peel guard costs to one taken branch per peeled loop. Change the cost model equation to consider vector iterations as the loop iterations less the prologue and epilogue iterations. Change outside vector cost check to less than or equal to zero instead of equal to zero. (vect_do_peeling_for_loop_bound): Reduce min_scalar_loop_bound by one. * tree-vectorizer.h: Add TARG_COND_TAKEN_BRANCH_COST and TARG_COND_NOT_TAKEN_BRANCH_COST. ... [1]: http://gcc.gnu.org/ml/gcc-cvs/2007-09/msg00347.html Uros.
