From aca4ab015f967d7878e718442e44e601eff9374f Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Mon, 19 Apr 2010 19:38:22 -0400
Subject: [PATCH] Fix removing  if assigned to unused var, bug248.

---
 Changes                          | 2 ++
 src/V3Dead.cpp                   | 5 +----
 test_regress/t/t_sys_file_scan.v | 9 +++++++--
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/Changes b/Changes
index 1370bd0d4..d4988feaa 100644
--- a/Changes
+++ b/Changes
@@ -17,6 +17,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 **** Fix bit reductions on multi-packed dimensions, bug227. [by Bryon Bradley]
 
+**** Fix removing $fscanf if assigned to unused var, bug248. [Ashutosh Das]
+
 **** Fix "make install" with configure outside srcdir.  [Stefan Wallentowitz]
 
 **** Fix loop unroller out of memory; change --unroll-stmts.  [Ashutosh Das]
diff --git a/src/V3Dead.cpp b/src/V3Dead.cpp
index f9195747b..222474d52 100644
--- a/src/V3Dead.cpp
+++ b/src/V3Dead.cpp
@@ -145,13 +145,10 @@ private:
 	    nodep->lhsp()->iterateAndNext(*this);
 	}
     }
-    virtual void visit(AstUCFunc* nodep, AstNUser*) {
-	m_sideEffect = true;  // If appears on assign RHS, don't ever delete the assignment
-	nodep->iterateChildren(*this);
-    }
 
     //-----
     virtual void visit(AstNode* nodep, AstNUser*) {
+	if (nodep->isOutputter()) m_sideEffect=true;
 	nodep->iterateChildren(*this);
     }
 
diff --git a/test_regress/t/t_sys_file_scan.v b/test_regress/t/t_sys_file_scan.v
index 79aa0073e..e94e580ea 100644
--- a/test_regress/t/t_sys_file_scan.v
+++ b/test_regress/t/t_sys_file_scan.v
@@ -14,9 +14,14 @@ module t;
       outfile = $fopen("obj_dir/t_sys_file_scan/t_sys_file_scan_test.log", "w");
 
       count = 1234;
-      $display("count == %d, infile %d, outfile %d", count, infile, outfile);
+`ifdef TEST_VERBOSE
+      $display("-count == %d, infile %d, outfile %d", count, infile, outfile);
+`endif
       count = $fscanf(infile, "%d\n", a);
-      $display("count == %d, infile %d, outfile %d", count, infile, outfile);
+`ifdef TEST_VERBOSE
+      // Ifdefing this out gave bug248
+      $display("-count == %d, infile %d, outfile %d", count, infile, outfile);
+`endif
       $fwrite(outfile, "# a\n");
       $fwrite(outfile, "%d\n", a);
       $fclose(infile);