From 8e8792a347c87dbb82b4cf75ec3452bc5cd1d3db Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Wed, 29 Jul 2020 09:59:01 +0200 Subject: [PATCH] tree-optimization/95679 - properly signal changes from propagate_into_phi_args This restores a lost setting of something_changed with the recent refactoring of the substitute and fold engine. The reported ICE in the PR was meanwhile mitigated in other ways but the issue can still result in missed optimizations via failed runs of CFG cleanup. 2020-07-29 Richard Biener PR tree-optimization/95679 * tree-ssa-propagate.h (substitute_and_fold_engine::propagate_into_phi_args): Return whether anything changed. * tree-ssa-propagate.c (substitute_and_fold_engine::propagate_into_phi_args): Likewise. (substitute_and_fold_dom_walker::before_dom_children): Update something_changed. --- gcc/tree-ssa-propagate.c | 15 +++++++++++---- gcc/tree-ssa-propagate.h | 2 +- 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/gcc/tree-ssa-propagate.c b/gcc/tree-ssa-propagate.c index 01ee7fd33eb..1e057284154 100644 --- a/gcc/tree-ssa-propagate.c +++ b/gcc/tree-ssa-propagate.c @@ -1017,11 +1017,13 @@ substitute_and_fold_dom_walker::foreach_new_stmt_in_bb } } -void +bool substitute_and_fold_engine::propagate_into_phi_args (basic_block bb) { edge e; edge_iterator ei; + bool propagated = false; + /* Visit BB successor PHI nodes and replace PHI args. */ FOR_EACH_EDGE (e, ei, bb->succs) { @@ -1035,11 +1037,16 @@ substitute_and_fold_engine::propagate_into_phi_args (basic_block bb) || virtual_operand_p (arg)) continue; tree val = get_value (arg, phi); - if (val && is_gimple_min_invariant (val) + if (val + && is_gimple_min_invariant (val) && may_propagate_copy (arg, val)) - propagate_value (use_p, val); + { + propagate_value (use_p, val); + propagated = true; + } } } + return propagated; } edge @@ -1229,7 +1236,7 @@ substitute_and_fold_dom_walker::before_dom_children (basic_block bb) } } - substitute_and_fold_engine->propagate_into_phi_args (bb); + something_changed |= substitute_and_fold_engine->propagate_into_phi_args (bb); return NULL; } diff --git a/gcc/tree-ssa-propagate.h b/gcc/tree-ssa-propagate.h index 24de43ebc6c..9406cdf8f51 100644 --- a/gcc/tree-ssa-propagate.h +++ b/gcc/tree-ssa-propagate.h @@ -115,7 +115,7 @@ class substitute_and_fold_engine virtual void pre_fold_stmt (gimple *) { } virtual void post_new_stmt (gimple *) { } - void propagate_into_phi_args (basic_block); + bool propagate_into_phi_args (basic_block); /* Users like VRP can set this when they want to perform folding for every propagation. */