After fixing PR51481 I noticed replace_uses_by does quite some
unnecessary work despite being (one of) the core propagator routine(s).
The following patch cleans it up to avoid doing useless work.
LTO bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
I'll apply this tomorrow.
Thanks,
Richard.
2011-12-13 Richard Guenther <rguent...@suse.de>
* tree-cfg.c (replace_uses_by): Only mark blocks altered
that will make a difference. Only recompute ADDR_EXPR
invariantness if it could possibly have changed. Do so
before folding the statement.
Index: gcc/tree-cfg.c
===================================================================
--- gcc/tree-cfg.c (revision 182285)
+++ gcc/tree-cfg.c (working copy)
@@ -1592,7 +1596,7 @@ replace_uses_by (tree name, tree val)
/* This can only occur for virtual operands, since
for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
would prevent replacement. */
- gcc_assert (!is_gimple_reg (name));
+ gcc_checking_assert (!is_gimple_reg (name));
SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
}
}
@@ -1604,28 +1608,37 @@ replace_uses_by (tree name, tree val)
gimple orig_stmt = stmt;
size_t i;
- fold_stmt (&gsi);
- stmt = gsi_stmt (gsi);
- if (cfgcleanup_altered_bbs && !is_gimple_debug (stmt))
+ /* Mark the block if we changed the last stmt in it. */
+ if (cfgcleanup_altered_bbs
+ && stmt_ends_bb_p (stmt))
bitmap_set_bit (cfgcleanup_altered_bbs, gimple_bb (stmt)->index);
- /* FIXME. This should go in update_stmt. */
- for (i = 0; i < gimple_num_ops (stmt); i++)
+ /* FIXME. It shouldn't be required to keep TREE_CONSTANT
+ on ADDR_EXPRs up-to-date on GIMPLE. Propagation will
+ only change sth from non-invariant to invariant, and only
+ when propagating integer constants. */
+ if (TREE_CODE (val) == INTEGER_CST)
+ for (i = 0; i < gimple_num_ops (stmt); i++)
+ {
+ tree op = gimple_op (stmt, i);
+ /* Operands may be empty here. For example, the labels
+ of a GIMPLE_COND are nulled out following the creation
+ of the corresponding CFG edges. */
+ if (op && TREE_CODE (op) == ADDR_EXPR)
+ recompute_tree_invariant_for_addr_expr (op);
+ }
+
+ if (fold_stmt (&gsi))
{
- tree op = gimple_op (stmt, i);
- /* Operands may be empty here. For example, the labels
- of a GIMPLE_COND are nulled out following the creation
- of the corresponding CFG edges. */
- if (op && TREE_CODE (op) == ADDR_EXPR)
- recompute_tree_invariant_for_addr_expr (op);
+ stmt = gsi_stmt (gsi);
+ maybe_clean_or_replace_eh_stmt (orig_stmt, stmt);
}
- maybe_clean_or_replace_eh_stmt (orig_stmt, stmt);
update_stmt (stmt);
}
}
- gcc_assert (has_zero_uses (name));
+ gcc_checking_assert (has_zero_uses (name));
/* Also update the trees stored in loop structures. */
if (current_loops)
