From 736b9074c8c7a18e07204857101c5a8d74eebac3 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Tue, 10 Nov 2009 16:40:07 -0500
Subject: [PATCH] Support for loop i++, ++i, i--, --i, bug175.

---
 Changes                     |  2 ++
 src/verilog.y               |  4 ++++
 test_regress/t/t_for_loop.v | 28 ++++++++++++++++++++++++++++
 3 files changed, 34 insertions(+)

diff --git a/Changes b/Changes
index 6d2c1ded2..2d280dbd5 100644
--- a/Changes
+++ b/Changes
@@ -20,6 +20,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 **** Support optional cell parenthesis, bug179. [by Byron Bradley]
 
+**** Support for loop i++, ++i, i--, --i, bug175. [by Byron Bradley]
+
 **** Fix Verilator core dump on wide integer divides, bug178. [Byron Bradley]
 
 * Verilator 3.720 2009/10/26
diff --git a/src/verilog.y b/src/verilog.y
index b55f87984..6d6fc5aaa 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -1837,6 +1837,10 @@ for_stepE<nodep>:		// IEEE: for_step + empty
 
 for_step<nodep>:		// IEEE: for_step
 		varRefBase '=' expr			{ $$ = new AstAssign($2,$1,$3); }
+	|	yP_PLUSPLUS   varRefBase		{ $$ = new AstAssign($1,$2,new AstAdd ($1,$2->cloneTree(true),new AstConst($1,V3Number($1,"'b1")))) }
+	|	yP_MINUSMINUS varRefBase		{ $$ = new AstAssign($1,$2,new AstSub ($1,$2->cloneTree(true),new AstConst($1,V3Number($1,"'b1")))) }
+	|	varRefBase yP_PLUSPLUS			{ $$ = new AstAssign($2,$1,new AstAdd ($2,$1->cloneTree(true),new AstConst($2,V3Number($2,"'b1")))) }
+	|	varRefBase yP_MINUSMINUS		{ $$ = new AstAssign($2,$1,new AstSub ($2,$1->cloneTree(true),new AstConst($2,V3Number($2,"'b1")))) }
 	//UNSUP: List of steps
 	;
 
diff --git a/test_regress/t/t_for_loop.v b/test_regress/t/t_for_loop.v
index 1883418f3..dd4b4d6d8 100644
--- a/test_regress/t/t_for_loop.v
+++ b/test_regress/t/t_for_loop.v
@@ -49,6 +49,34 @@ module t (/*AUTOARG*/
 	    loops = loops + 1;
 	 end
 	 if (loops !== 100000) $stop;
+	 // Test post-increment
+	 loops = 0;
+	 for (i=0; i<=16; i++) begin
+	    loops = loops + 1;
+	 end
+	 if (i !== 17) $stop;
+	 if (loops !== 17) $stop;
+	 // Test pre-increment
+	 loops = 0;
+	 for (i=0; i<=16; ++i) begin
+	    loops = loops + 1;
+	 end
+	 if (i !== 17) $stop;
+	 if (loops !== 17) $stop;
+	 // Test post-decrement
+	 loops = 0;
+	 for (i=16; i>=0; i--) begin
+	    loops = loops + 1;
+	 end
+	 if (i !== -1) $stop;
+	 if (loops !== 17) $stop;
+	 // Test pre-decrement
+	 loops = 0;
+	 for (i=16; i>=0; --i) begin
+	    loops = loops + 1;
+	 end
+	 if (i !== -1) $stop;
+	 if (loops !== 17) $stop;
 	 //
 	 $write("*-* All Finished *-*\n");
 	 $finish;