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From: "wschmidt at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/57993] [4.9 Regression] ICE: verify_ssa failed (definition in block n does not dominate use in block m) Date: Fri, 26 Jul 2013 18:18:00 -0000 [thread overview] Message-ID: <bug-57993-4-Vg2DzAlJhW@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-57993-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57993 --- Comment #6 from Bill Schmidt <wschmidt at gcc dot gnu.org> --- Here's the patch I'm currently testing, which corrects the problem for this test case. We'll see how it does on regressions. Index: gcc/gimple-ssa-strength-reduction.c =================================================================== --- gcc/gimple-ssa-strength-reduction.c (revision 201267) +++ gcc/gimple-ssa-strength-reduction.c (working copy) @@ -2179,6 +2179,18 @@ phi_add_costs (gimple phi, slsr_cand_t c, int one_ int cost = 0; slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); + /* If we work our way back to a phi that isn't dominated by the hidden + basis, this isn't a candidate for replacement. Indicate this by + returning an unreasonably high cost. It's not easy to detect + these situations when determining the basis, so we defer the + decision until now. */ + basic_block phi_bb = gimple_bb (phi_cand->cand_stmt); + slsr_cand_t basis = lookup_cand (c->basis); + basic_block basis_bb = gimple_bb (basis->cand_stmt); + + if (phi_bb == basis_bb || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb)) + return COST_INFINITE; + for (i = 0; i < gimple_phi_num_args (phi); i++) { tree arg = gimple_phi_arg_def (phi, i);
next prev parent reply other threads:[~2013-07-26 18:18 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-07-26 11:30 [Bug tree-optimization/57993] New: " antoine.balestrat at gmail dot com 2013-07-26 12:54 ` [Bug tree-optimization/57993] [4.9 Regression] " mpolacek at gcc dot gnu.org 2013-07-26 13:14 ` mpolacek at gcc dot gnu.org 2013-07-26 16:36 ` wschmidt at gcc dot gnu.org 2013-07-26 16:46 ` mpolacek at gcc dot gnu.org 2013-07-26 17:25 ` wschmidt at gcc dot gnu.org 2013-07-26 18:18 ` wschmidt at gcc dot gnu.org [this message] 2013-07-28 0:53 ` wschmidt at gcc dot gnu.org 2013-07-30 1:02 ` wschmidt at gcc dot gnu.org 2013-08-03 14:42 ` wschmidt at gcc dot gnu.org
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