From bd264006efcf3dc793e565d1e5b134cd16a57e83 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Tue, 27 Feb 2007 14:30:22 +0000
Subject: [PATCH] Fix empty for blocks

git-svn-id: file://localhost/svn/verilator/trunk/verilator@888 77ca24e4-aefa-0310-84f0-b9a241c72d87
---
 Changes                          | 14 +++++++++-----
 src/V3Unroll.cpp                 |  7 ++++++-
 test_regress/t/t_unroll_signed.v | 11 +++++++++++
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/Changes b/Changes
index a4ea1bf94..f0afd53fc 100644
--- a/Changes
+++ b/Changes
@@ -3,11 +3,15 @@ Revision history for Verilator
 The contributors that suggested a given feature are shown in [].  [by ...]
 indicates the contributor was also the author of the fix; Thanks!
 
+* Verilator 3.63**
+
+**** Fix internal error when public for loop has empty body.  [David Addison]
+
 * Verilator 3.633 2/7/2007
 
 ***  Add --trace-depth option for minimizing VCD file size. [Emerson Suguimoto]
 
-***  With VL_DEBUG, show wires causing convergance errors. [Mike Shinkarovsky]
+***  With VL_DEBUG, show wires causing convergence errors. [Mike Shinkarovsky]
 
 **** Fix isolate_assignments when many signals per always. [Mike Shinkarovsky]
 
@@ -95,7 +99,7 @@ indicates the contributor was also the author of the fix; Thanks!
 
 **** Removed coverage request variable; see Coverage limitations in docs.
 
-**** Fix DOS carrage returns in multiline defines.  [Ralf Karge]
+**** Fix DOS carriage returns in multiline defines.  [Ralf Karge]
 
 **** Fix printf format warnings on 64-bit linux.
 
@@ -107,7 +111,7 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ***  Added --inhibit-sim flag for environments using old __Vm_inhibitSim.
 
-***  Added `systemc_dtor for destructor extentions.  [Allan Cochrane]
+***  Added `systemc_dtor for destructor extensions.  [Allan Cochrane]
 
 ***  Added -MP to make phony dependencies, ala GCC's.
 
@@ -142,7 +146,7 @@ indicates the contributor was also the author of the fix; Thanks!
 
 **** Fix extraneous UNSIGNED warning when comparing genvars.  [David Hewson]
 
-**** Fix extra whitespace in $display %c.  [by David Addison]
+**** Fix extra white space in $display %c.  [by David Addison]
 
 **** vl_finish and vl_fatal now print via VL_PRINTF rather then cerr/cout.
 
@@ -245,7 +249,7 @@ indicates the contributor was also the author of the fix; Thanks!
 
 **** Fix functions where regs are declared before inputs.  [Danny Ding]
 
-**** Fix bad deep expressions with bitselects and rotate.  [Prabhat Gupta]
+**** Fix bad deep expressions with bit-selects and rotate.  [Prabhat Gupta]
 
 * Verilator 3.500 10/30/2005 Stable
 
diff --git a/src/V3Unroll.cpp b/src/V3Unroll.cpp
index 644519f54..122b32572 100644
--- a/src/V3Unroll.cpp
+++ b/src/V3Unroll.cpp
@@ -252,7 +252,12 @@ private:
 			if (clonedIncsp) {
 			    // Previous iteration of loop set the variable.
 			    // This set is redundant with this next iteration and can be removed.
-			    clonedIncsp->unlinkFrBack()->deleteTree();
+			    if (clonedIncsp == newbodysp) {  // Increment was only thing in list
+				newbodysp = NULL;
+			    } else {
+				clonedIncsp->unlinkFrBack();
+			    }
+			    clonedIncsp->deleteTree();
 			}
 			clonedIncsp = incp->clonep(); if (!clonedIncsp) nodep->v3fatalSrc("inc failed");
 		    }
diff --git a/test_regress/t/t_unroll_signed.v b/test_regress/t/t_unroll_signed.v
index 9f3a379b9..04ff3dd9c 100644
--- a/test_regress/t/t_unroll_signed.v
+++ b/test_regress/t/t_unroll_signed.v
@@ -11,6 +11,17 @@ module t (/*AUTOARG*/
 
    input clk;
 
+   // Check empty blocks
+   task EmptyFor;
+      /* verilator public */
+      integer i;
+      begin
+         for (i = 0; i < 2; i = i+1)
+           begin
+           end
+      end
+   endtask
+
    // Check look unroller
    reg signed	   signed_tests_only = 1'sb1;
    integer 	   total;