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re PR tree-optimization/49822 (Segfault in remove_prop_source_from_use)

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2011-07-25  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/49822
	* tree-ssa-forwprop.c (remove_prop_source_from_use): Robustify
	more.  Make sure to preserve stmts with side-effects.  Properly
	handle virtual defs, follow a longer def chain.

From-SVN: r176745
This commit is contained in:
Richard Guenther 2011-07-25 14:15:02 +00:00 • committed by Richard Biener
parent 1baae426f9
commit 7fdab8d4fc
2 changed files with 22 additions and 7 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2011-07-25 Richard Guenther <rguenther@suse.de>
PR tree-optimization/49822
* tree-ssa-forwprop.c (remove_prop_source_from_use): Robustify
more. Make sure to preserve stmts with side-effects. Properly
handle virtual defs, follow a longer def chain.
2011-07-22 Romain Geissler <romain.geissler@gmail.com>
PR plugins/45348

22
gcc/tree-ssa-forwprop.c
View file

@ -295,9 +295,12 @@ can_propagate_from (gimple def_stmt)
return true;
}
/* Remove a copy chain ending in NAME along the defs.
/* Remove a chain of dead statements starting at the definition of
NAME. The chain is linked via the first operand of the defining statements.
If NAME was replaced in its only use then this function can be used
to clean up dead stmts. Returns true if cleanup-cfg has to run. */
to clean up dead stmts. The function handles already released SSA
names gracefully.
Returns true if cleanup-cfg has to run. */
static bool
remove_prop_source_from_use (tree name)
@ -309,19 +312,24 @@ remove_prop_source_from_use (tree name)
do {
basic_block bb;
if (!has_zero_uses (name))
if (SSA_NAME_IN_FREE_LIST (name)
|| SSA_NAME_IS_DEFAULT_DEF (name)
|| !has_zero_uses (name))
return cfg_changed;
stmt = SSA_NAME_DEF_STMT (name);
bb = gimple_bb (stmt);
if (!bb)
if (gimple_code (stmt) == GIMPLE_PHI
|| gimple_has_side_effects (stmt))
return cfg_changed;
bb = gimple_bb (stmt);
gsi = gsi_for_stmt (stmt);
release_defs (stmt);
unlink_stmt_vdef (stmt);
gsi_remove (&gsi, true);
release_defs (stmt);
cfg_changed |= gimple_purge_dead_eh_edges (bb);
name = (gimple_assign_copy_p (stmt)) ? gimple_assign_rhs1 (stmt) : NULL;
name = is_gimple_assign (stmt) ? gimple_assign_rhs1 (stmt) : NULL_TREE;
} while (name && TREE_CODE (name) == SSA_NAME);
return cfg_changed;