From: Clifford Wolf <clifford@clifford.at>
Date: Mon, 22 Apr 2019 16:19:02 +0000 (+0200)
Subject: Determine correct signedness and expression width in for loop unrolling, fixes #370
X-Git-Tag: yosys-0.9~172^2
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=4ad0ea5c3c325dc639829f6c6836353044585af5;p=yosys.git

Determine correct signedness and expression width in for loop unrolling, fixes #370

Signed-off-by: Clifford Wolf <clifford@clifford.at>
---

diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 76da5a97c..3e453bd7f 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -1085,7 +1085,12 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 
 		// eval 1st expression
 		AstNode *varbuf = init_ast->children[1]->clone();
-		while (varbuf->simplify(true, false, false, stage, 32, true, false)) { }
+		{
+			int expr_width_hint = -1;
+			bool expr_sign_hint = true;
+			varbuf->detectSignWidth(expr_width_hint, expr_sign_hint);
+			while (varbuf->simplify(true, false, false, stage, 32, true, false)) { }
+		}
 
 		if (varbuf->type != AST_CONSTANT)
 			log_file_error(filename, linenum, "Right hand side of 1st expression of generate for-loop is not constant!\n");
@@ -1107,7 +1112,12 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		{
 			// eval 2nd expression
 			AstNode *buf = while_ast->clone();
-			while (buf->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
+			{
+				int expr_width_hint = -1;
+				bool expr_sign_hint = true;
+				buf->detectSignWidth(expr_width_hint, expr_sign_hint);
+				while (buf->simplify(true, false, false, stage, expr_width_hint, expr_sign_hint, false)) { }
+			}
 
 			if (buf->type != AST_CONSTANT)
 				log_file_error(filename, linenum, "2nd expression of generate for-loop is not constant!\n");
@@ -1148,7 +1158,12 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 
 			// eval 3rd expression
 			buf = next_ast->children[1]->clone();
-			while (buf->simplify(true, false, false, stage, 32, true, false)) { }
+			{
+				int expr_width_hint = -1;
+				bool expr_sign_hint = true;
+				buf->detectSignWidth(expr_width_hint, expr_sign_hint);
+				while (buf->simplify(true, false, false, stage, expr_width_hint, expr_sign_hint, true)) { }
+			}
 
 			if (buf->type != AST_CONSTANT)
 				log_file_error(filename, linenum, "Right hand side of 3rd expression of generate for-loop is not constant!\n");