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tree-optimization/106186 - propagate out virtual LC PHI nodes properly 

The code to remove LC PHI nodes in clean_up_loop_closed_phi does not handle
virtual operands because may_propagate_copy generally returns false
for them.  The following copies the merge_blocks variant for
dealing with them.

This fixes a missed jump threading in gcc.dg/auto-init-uninit-4.c
which manifests in bogus uninit diagnostics.

	PR tree-optimization/106186
	* tree-ssa-propagate.cc (clean_up_loop_closed_phi):
	Properly handle virtual PHI nodes.
This commit is contained in:
Richard Biener 2022-07-05 11:38:52 +02:00
parent 1a6e0d8252
commit c3d2600cfb
1 changed files with 15 additions and 1 deletions
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16
gcc/tree-ssa-propagate.cc
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@ -1272,7 +1272,21 @@ clean_up_loop_closed_phi (function *fun)
rhs = gimple_phi_arg_def (phi, 0);
lhs = gimple_phi_result (phi);
if (rhs && may_propagate_copy (lhs, rhs))
if (virtual_operand_p (rhs))
{
imm_use_iterator iter;
use_operand_p use_p;
gimple *stmt;
FOR_EACH_IMM_USE_STMT (stmt, iter, lhs)
FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
SET_USE (use_p, rhs);
if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
remove_phi_node (&gsi, true);
}
else if (may_propagate_copy (lhs, rhs))
{
/* Dump details. */
if (dump_file && (dump_flags & TDF_DETAILS))