http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53774
--- Comment #5 from rguenther at suse dot de <rguenther at suse dot de> 2012-06-27 08:28:27 UTC --- On Tue, 26 Jun 2012, wschmidt at gcc dot gnu.org wrote: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53774 > > --- Comment #3 from William J. Schmidt <wschmidt at gcc dot gnu.org> > 2012-06-26 18:42:41 UTC --- > I wonder why fp_6(D) gets a rank of zero. Is it an uninitialized variable or > a > parameter? Parms are supposed to get small positive numbers for ranks. Maybe > the "right" fix is to force fp_6(D) to get a nonzero rank? Yes, fp_6(D) is not initialized. It also seems that ranks for non-constants are based on zero, too, as for example loop-carried PHIs also might get a rank of zero. Parameters get ranks starting off 3 (see init_reassoc). I suppose we could instead of walking over DECL_ARGUMENTS simply walk over all SSA names and assign ranks to all default-defs instead. I'm going to test that. Ah, it's if (TREE_CODE (SSA_NAME_VAR (e)) == PARM_DECL && SSA_NAME_IS_DEFAULT_DEF (e)) return find_operand_rank (e); stmt = SSA_NAME_DEF_STMT (e); if (gimple_bb (stmt) == NULL) return 0; in get_rank - that will return zero for all non-param default-defs, even for the static chain we try to setup properly :/ Yeah, the following works - thanks for the hint ;) Index: gcc/tree-ssa-reassoc.c =================================================================== --- gcc/tree-ssa-reassoc.c (revision 188987) +++ gcc/tree-ssa-reassoc.c (working copy) @@ -383,14 +383,10 @@ get_rank (tree e) int i, n; tree op; - if (TREE_CODE (SSA_NAME_VAR (e)) == PARM_DECL - && SSA_NAME_IS_DEFAULT_DEF (e)) + if (SSA_NAME_IS_DEFAULT_DEF (e)) return find_operand_rank (e); stmt = SSA_NAME_DEF_STMT (e); - if (gimple_bb (stmt) == NULL) - return 0; - if (gimple_code (stmt) == GIMPLE_PHI) return phi_rank (stmt); @@ -3647,7 +3643,6 @@ init_reassoc (void) { int i; long rank = 2; - tree param; int *bbs = XNEWVEC (int, last_basic_block + 1); /* Find the loops, so that we can prevent moving calculations in @@ -3666,24 +3661,13 @@ init_reassoc (void) bb_rank = XCNEWVEC (long, last_basic_block + 1); operand_rank = pointer_map_create (); - /* Give each argument a distinct rank. */ - for (param = DECL_ARGUMENTS (current_function_decl); - param; - param = DECL_CHAIN (param)) - { - if (gimple_default_def (cfun, param) != NULL) - { - tree def = gimple_default_def (cfun, param); - insert_operand_rank (def, ++rank); - } - } - - /* Give the chain decl a distinct rank. */ - if (cfun->static_chain_decl != NULL) - { - tree def = gimple_default_def (cfun, cfun->static_chain_decl); - if (def != NULL) - insert_operand_rank (def, ++rank); + /* Give each default definition a distinct rank. This includes + parameters and the static chain. */ + for (i = 1; i < (int) num_ssa_names; ++i) + { + tree name = ssa_name (i); + if (name && SSA_NAME_IS_DEFAULT_DEF (name)) + insert_operand_rank (name, ++rank); } /* Set up rank for each BB */
