From 19353855bfc05914faaee9f297684f608fd9a485 Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Thu, 12 Jul 2018 07:08:34 +0000
Subject: tree-ssa-sccvn.c (mprts_hook_cnt): Remove.

2018-07-12  Richard Biener  <rguenther@suse.de>

	* tree-ssa-sccvn.c (mprts_hook_cnt): Remove.
	(vn_lookup_simplify_result): Remove recursion limit applied
	here.
	(vn_nary_build_or_lookup_1): Adjust.
	(try_to_simplify): Likewise.
	* gimple-match-head.c (gimple_resimplify1): Instead apply one
	here.
	(gimple_resimplify2): Likewise.
	(gimple_resimplify3): Likewise.
	(gimple_resimplify4): Likewise.

From-SVN: r262573
---
 gcc/gimple-match-head.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

(limited to 'gcc/gimple-match-head.c')

diff --git a/gcc/gimple-match-head.c b/gcc/gimple-match-head.c
index 1a12bb35e01..c5a19239798 100644
--- a/gcc/gimple-match-head.c
+++ b/gcc/gimple-match-head.c
@@ -97,13 +97,30 @@ gimple_resimplify1 (gimple_seq *seq, gimple_match_op *res_op,
 	}
     }
 
+  /* Limit recursion, there are cases like PR80887 and others, for
+     example when value-numbering presents us with unfolded expressions
+     that we are really not prepared to handle without eventual
+     oscillation like ((_50 + 0) + 8) where _50 gets mapped to _50
+     itself as available expression.  */
+  static unsigned depth;
+  if (depth > 10)
+    {
+      if (dump_file && (dump_flags & TDF_FOLDING))
+	fprintf (dump_file, "Aborting expression simplification due to "
+		 "deep recursion\n");
+      return false;
+    }
+
+  ++depth;
   gimple_match_op res_op2 (*res_op);
   if (gimple_simplify (&res_op2, seq, valueize,
 		       res_op->code, res_op->type, res_op->ops[0]))
     {
+      --depth;
       *res_op = res_op2;
       return true;
     }
+  --depth;
 
   return false;
 }
@@ -151,14 +168,27 @@ gimple_resimplify2 (gimple_seq *seq, gimple_match_op *res_op,
       canonicalized = true;
     }
 
+  /* Limit recursion, see gimple_resimplify1.  */
+  static unsigned depth;
+  if (depth > 10)
+    {
+      if (dump_file && (dump_flags & TDF_FOLDING))
+	fprintf (dump_file, "Aborting expression simplification due to "
+		 "deep recursion\n");
+      return false;
+    }
+
+  ++depth;
   gimple_match_op res_op2 (*res_op);
   if (gimple_simplify (&res_op2, seq, valueize,
 		       res_op->code, res_op->type,
 		       res_op->ops[0], res_op->ops[1]))
     {
+      --depth;
       *res_op = res_op2;
       return true;
     }
+  --depth;
 
   return canonicalized;
 }
@@ -205,14 +235,27 @@ gimple_resimplify3 (gimple_seq *seq, gimple_match_op *res_op,
       canonicalized = true;
     }
 
+  /* Limit recursion, see gimple_resimplify1.  */
+  static unsigned depth;
+  if (depth > 10)
+    {
+      if (dump_file && (dump_flags & TDF_FOLDING))
+	fprintf (dump_file, "Aborting expression simplification due to "
+		 "deep recursion\n");
+      return false;
+    }
+
+  ++depth;
   gimple_match_op res_op2 (*res_op);
   if (gimple_simplify (&res_op2, seq, valueize,
 		       res_op->code, res_op->type,
 		       res_op->ops[0], res_op->ops[1], res_op->ops[2]))
     {
+      --depth;
       *res_op = res_op2;
       return true;
     }
+  --depth;
 
   return canonicalized;
 }
@@ -229,15 +272,28 @@ gimple_resimplify4 (gimple_seq *seq, gimple_match_op *res_op,
 {
   /* No constant folding is defined for four-operand functions.  */
 
+  /* Limit recursion, see gimple_resimplify1.  */
+  static unsigned depth;
+  if (depth > 10)
+    {
+      if (dump_file && (dump_flags & TDF_FOLDING))
+	fprintf (dump_file, "Aborting expression simplification due to "
+		 "deep recursion\n");
+      return false;
+    }
+
+  ++depth;
   gimple_match_op res_op2 (*res_op);
   if (gimple_simplify (&res_op2, seq, valueize,
 		       res_op->code, res_op->type,
 		       res_op->ops[0], res_op->ops[1], res_op->ops[2],
 		       res_op->ops[3]))
     {
+      --depth;
       *res_op = res_op2;
       return true;
     }
+  --depth;
 
   return false;
 }
-- 
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