From e8dada7337d97d53e26306ed2bfe84174bec8fa6 Mon Sep 17 00:00:00 2001
From: Cary R <cygcary@yahoo.com>
Date: Fri, 25 Sep 2009 17:23:53 -0700
Subject: [PATCH] The concat object can get out of sequence so don't optimize a
 repeat.

Under some situation the optimized repeat expression can get out
of sync while it is being processed this causes the code to
reference freed memory. This happens when the repeat expression
is converted to an unsigned integer, but the repeat expression
is used in a different path. It was easier to just remove the
optimization then track down the convoluted call sequence that
was causing this and then figure out what needed to be fixed.
The repeat expression must be constant, so is likely not too
complicated so this optimization is very minor and should not
be missed.
(cherry picked from commit 3259354d293d224108bb61a5d5827deca48c4d7f)
---
 PExpr.h      |  1 -
 elab_expr.cc | 24 ++++++------------------
 2 files changed, 6 insertions(+), 19 deletions(-)

diff --git a/PExpr.h b/PExpr.h
index 00c3c2fee..791e68bbd 100644
--- a/PExpr.h
+++ b/PExpr.h
@@ -183,7 +183,6 @@ class PEConcat : public PExpr {
       std::valarray<unsigned>tested_widths_;
 
       PExpr*repeat_;
-      NetExpr*repeat_expr_;
 };
 
 /*
diff --git a/elab_expr.cc b/elab_expr.cc
index 89698a49a..5d4f30bba 100644
--- a/elab_expr.cc
+++ b/elab_expr.cc
@@ -1564,8 +1564,8 @@ unsigned PEConcat::test_width(Design*des, NetScope*scope,
 	      // Try to evaluate the repeat expression now, so
 	      // that we can give the caller an accurate
 	      // expression width.
-	    repeat_expr_ = elab_and_eval(des, scope, repeat_, -1);
-	    if (NetEConst*tmp_c = dynamic_cast<NetEConst*> (repeat_expr_)) {
+	    NetExpr*tmp = elab_and_eval(des, scope, repeat_, -1);
+	    if (NetEConst*tmp_c = dynamic_cast<NetEConst*> (tmp)) {
 		  repeat_count = tmp_c->value().as_ulong();
 
 	    } else {
@@ -1605,22 +1605,10 @@ NetExpr* PEConcat::elaborate_expr(Design*des, NetScope*scope,
 	/* If there is a repeat expression, then evaluate the constant
 	   value and set the repeat count. */
       if (repeat_) {
-	    NetExpr*tmp;
-	    if (repeat_expr_ == 0) {
-		    // If the expression has not yet been elaborated,
-		    // then try now.
-		  need_constant_expr = true;
-		  tmp = elab_and_eval(des, scope, repeat_, -1);
-		  need_constant_expr = false;
-		  assert(tmp);
-	    } else {
-		    // If it has been elaborated, make sure it is
-		    // fully evaluated.
-		  tmp = repeat_expr_;
-		  need_constant_expr = true;
-		  eval_expr(tmp);
-		  need_constant_expr = false;
-	    }
+	    need_constant_expr = true;
+	    NetExpr*tmp = elab_and_eval(des, scope, repeat_, -1);
+	    need_constant_expr = false;
+	    assert(tmp);
 
 	    if (tmp->expr_type() == IVL_VT_REAL) {
 		  cerr << tmp->get_fileline() << ": error: Concatenation "