From 6522add29b65f7fe572202b2a1e83a8cd00b07fa Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 28 Nov 2016 15:03:55 +0000 Subject: re PR tree-optimization/78542 (wrong code at -Og results in endless loop) 2016-11-28 Richard Biener PR tree-optimization/78542 * tree-ssa-ccp.c (evaluate_stmt): Only valueize simplification if allowed. * gcc.dg/torture/pr78542.c: New testcase. From-SVN: r242920 --- gcc/tree-ssa-ccp.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'gcc/tree-ssa-ccp.c') diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c index f89da708f42..084b2e1dace 100644 --- a/gcc/tree-ssa-ccp.c +++ b/gcc/tree-ssa-ccp.c @@ -1744,7 +1744,12 @@ evaluate_stmt (gimple *stmt) { fold_defer_overflow_warnings (); simplified = ccp_fold (stmt); - if (simplified && TREE_CODE (simplified) == SSA_NAME) + if (simplified + && TREE_CODE (simplified) == SSA_NAME + /* We may not use values of something that may be simulated again, + see valueize_op_1. */ + && (SSA_NAME_IS_DEFAULT_DEF (simplified) + || ! prop_simulate_again_p (SSA_NAME_DEF_STMT (simplified)))) { ccp_prop_value_t *val = get_value (simplified); if (val && val->lattice_val != VARYING) -- cgit v1.2.3