From: Alexandre Oliva <oliva@adacore.com>
Date: Thu, 29 Dec 2022 17:32:46 +0000 (-0300)
Subject: scoped tables: insert before further lookups
X-Git-Tag: upstream/13.1.0~2326
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=26be8b84603be48d1cf35bea3be2bb398f7964b7;p=platform%2Fupstream%2Fgcc.git

scoped tables: insert before further lookups

Avoid hash table lookups between requesting an insert and storing the
inserted value in avail_exprs_stack.  Lookups before the insert is
completed could fail to find double-hashed elements.


for  gcc/ChangeLog

	* tree-ssa-scopedtables.cc
	(avail_exprs_stack::lookup_avail_expr): Finish hash table
	insertion before further lookups.
---

diff --git a/gcc/tree-ssa-scopedtables.cc b/gcc/tree-ssa-scopedtables.cc
index 6d203ef..3e6e129 100644
--- a/gcc/tree-ssa-scopedtables.cc
+++ b/gcc/tree-ssa-scopedtables.cc
@@ -259,11 +259,6 @@ avail_exprs_stack::lookup_avail_expr (gimple *stmt, bool insert, bool tbaa_p,
     }
   else if (*slot == NULL)
     {
-      /* If we did not find the expression in the hash table, we may still
-	 be able to produce a result for some expressions.  */
-      tree retval = avail_exprs_stack::simplify_binary_operation (stmt,
-								  element);
-
       /* We have, in effect, allocated *SLOT for ELEMENT at this point.
 	 We must initialize *SLOT to a real entry, even if we found a
 	 way to prove ELEMENT was a constant after not finding ELEMENT
@@ -277,6 +272,11 @@ avail_exprs_stack::lookup_avail_expr (gimple *stmt, bool insert, bool tbaa_p,
       class expr_hash_elt *element2 = new expr_hash_elt (element);
       *slot = element2;
 
+      /* If we did not find the expression in the hash table, we may still
+	 be able to produce a result for some expressions.  */
+      tree retval = avail_exprs_stack::simplify_binary_operation (stmt,
+								  element);
+
       record_expr (element2, NULL, '2');
       return retval;
     }