From 2117fe414ec414105cf57683277a618f07252aaf Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Wed, 14 Sep 2016 20:27:20 -0400
Subject: [PATCH] Fix error on wide numbers that represent shifts, bug1088.

---
 Changes                         |  2 +-
 src/V3Premit.cpp                |  5 +++++
 src/V3Width.cpp                 |  3 ---
 test_regress/t/t_param_shift.pl | 18 ++++++++++++++++++
 test_regress/t/t_param_shift.v  | 30 ++++++++++++++++++++++++++++++
 5 files changed, 54 insertions(+), 4 deletions(-)
 create mode 100755 test_regress/t/t_param_shift.pl
 create mode 100644 test_regress/t/t_param_shift.v

diff --git a/Changes b/Changes
index dcb0312cd..6f7bb82ee 100644
--- a/Changes
+++ b/Changes
@@ -12,7 +12,7 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ****  Fix SystemC compiles with VPI, bug1081. [Arthur Kahlich]
 
-****  Fix error on wide numbers that represent msb/lsb or shifts, msg1991. [Mandy Xu]
+****  Fix error on wide numbers that represent shifts, msg1991, bug1088. [Mandy Xu]
 
 ****  Improve Verilation performance on internal strings, msg1975. [Johan Bjork]
 
diff --git a/src/V3Premit.cpp b/src/V3Premit.cpp
index a570764cc..e5e90679a 100644
--- a/src/V3Premit.cpp
+++ b/src/V3Premit.cpp
@@ -263,6 +263,11 @@ private:
 	// Shifts of > 32/64 bits in C++ will wrap-around and generate non-0s
 	if (!nodep->user2SetOnce()) {
 	    UINFO(4,"  ShiftFix  "<<nodep<<endl);
+	    AstConst* shiftp = nodep->rhsp()->castConst();
+	    if (shiftp && shiftp->num().mostSetBitP1() > 32) {
+		shiftp->v3error("Unsupported: Shifting of by over 32-bit number isn't supported."
+				<<" (This isn't a shift of 32 bits, but a shift of 2^32, or 4 billion!)\n");
+	    }
 	    if (nodep->widthMin()<=64  // Else we'll use large operators which work right
 		// C operator's width must be < maximum shift which is based on Verilog width
 		&& nodep->width() < (1LL<<nodep->rhsp()->widthMin())) {
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index b8b3227e8..7d9e3ecaf 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -2632,9 +2632,6 @@ private:
 		    AstNode* shiftp = nodep->rhsp();
 		    nodep->rhsp()->replaceWith(new AstConst(shiftp->fileline(), num));
 		    shiftp->deleteTree(); VL_DANGLING(shiftp);
-		} else if (!m_paramsOnly) {
-		    nodep->rhsp()->v3error("Unsupported: Shifting of by over 32-bit number isn't supported."
-					   <<" (This isn't a shift of 32 bits, but a shift of 2^32, or 4 billion!)\n");
 		}
 	    }
 	}
diff --git a/test_regress/t/t_param_shift.pl b/test_regress/t/t_param_shift.pl
new file mode 100755
index 000000000..f91289753
--- /dev/null
+++ b/test_regress/t/t_param_shift.pl
@@ -0,0 +1,18 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+compile (
+    );
+
+execute (
+    check_finished=>1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_param_shift.v b/test_regress/t/t_param_shift.v
new file mode 100644
index 000000000..cc493a10e
--- /dev/null
+++ b/test_regress/t/t_param_shift.v
@@ -0,0 +1,30 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2016 by Mandy Xu.
+
+module t
+  #(parameter[95:0] P = 1)
+   (input clk);
+
+   localparam [32:0] M = 4;
+
+   function [M:0] gen_matrix;
+      gen_matrix[0] = 1>> M;
+   endfunction
+
+   reg [95: 0] lfsr = 0;
+   always @(posedge clk) begin
+      lfsr <= (1 >> P);
+   end
+
+   wire [95: 0] lfsr_w = 1 >> P;
+
+   localparam [95: 0] lfsr_p = 1 >> P;
+
+   initial begin
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule