From 759852914df00609f8797315c6cec76f1c8a3981 Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Mon, 12 Aug 2013 14:47:50 +0200
Subject: [PATCH] Added support for "2**n" shifter encoding

---
 frontends/ast/genrtlil.cc |  4 +++
 tests/simple/operators.v  | 53 +++++++++++++++++++++------------------
 2 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc
index 9c027878a..50e959754 100644
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@@ -974,8 +974,12 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 					width = width_hint;
 				if (type == AST_MUL)
 					width = std::min(left.width + right.width, width_hint);
+				if (type == AST_POW)
+					width = width_hint;
 			}
 			is_signed = children[0]->is_signed && children[1]->is_signed;
+			if (!flag_noopt && type == AST_POW && left.is_fully_const() && left.as_int() == 2)
+				return binop2rtlil(this, "$shl", width, RTLIL::SigSpec(1, left.width), right);
 			return binop2rtlil(this, type_name, width, left, right);
 		}
 
diff --git a/tests/simple/operators.v b/tests/simple/operators.v
index 6ca6ca7a8..7439101c8 100644
--- a/tests/simple/operators.v
+++ b/tests/simple/operators.v
@@ -86,30 +86,35 @@ always @(posedge clk) begin
 		58: y <= s1 % u2;
 		59: y <= s1 % s2;
 
-		60: y <= +u1;
-		61: y <= -u1;
-		62: y <= ~u1;
-		63: y <= !u1;
-
-		64: y <= +s1;
-		65: y <= -s1;
-		66: y <= ~s1;
-		67: y <= !s1;
-
-		68: y <= { &u1, ~&u1, |u1, ~|u1, ^u1, ~^u1, ^~u1 };
-		69: y <= { &s1, ~&s1, |s1, ~|s1, ^s1, ~^s1, ^~s1 };
-		70: y <= { &u1[1:0], ~&u1[1:0], |u1[1:0], ~|u1[1:0], ^u1[1:0], ~^u1[1:0], ^~u1[1:0] };
-		71: y <= { &s1[1:0], ~&s1[1:0], |s1[1:0], ~|s1[1:0], ^s1[1:0], ~^s1[1:0], ^~s1[1:0] };
-
-		72: y <= { u1[1:0] && u2[1:0], u1[1:0] && u2[1:0], !u1[1:0] };
-		73: y <= {4{u1[1:0]}};
-		74: y <= {u1, u2} ^ {s1, s2};
-		75: y <= {u1, u2} & {s1, s2};
-
-		76: y <= u1[0] ? u1 : u2;
-		77: y <= u1[0] ? u1 : s2;
-		78: y <= u1[0] ? s1 : u2;
-		79: y <= u1[0] ? s1 : s2;
+		60: y <= 4'd2 ** u1;
+		61: y <= 4'd2 ** s1;
+		62: y <= 4'sd2 ** u1;
+		63: y <= 4'sd2 ** s1;
+
+		64: y <= +u1;
+		65: y <= -u1;
+		66: y <= ~u1;
+		67: y <= !u1;
+
+		68: y <= +s1;
+		69: y <= -s1;
+		70: y <= ~s1;
+		71: y <= !s1;
+
+		72: y <= { &u1, ~&u1, |u1, ~|u1, ^u1, ~^u1, ^~u1 };
+		73: y <= { &s1, ~&s1, |s1, ~|s1, ^s1, ~^s1, ^~s1 };
+		74: y <= { &u1[1:0], ~&u1[1:0], |u1[1:0], ~|u1[1:0], ^u1[1:0], ~^u1[1:0], ^~u1[1:0] };
+		75: y <= { &s1[1:0], ~&s1[1:0], |s1[1:0], ~|s1[1:0], ^s1[1:0], ~^s1[1:0], ^~s1[1:0] };
+
+		76: y <= { u1[1:0] && u2[1:0], u1[1:0] && u2[1:0], !u1[1:0] };
+		77: y <= {4{u1[1:0]}};
+		78: y <= {u1, u2} ^ {s1, s2};
+		79: y <= {u1, u2} & {s1, s2};
+
+		80: y <= u1[0] ? u1 : u2;
+		81: y <= u1[0] ? u1 : s2;
+		82: y <= u1[0] ? s1 : u2;
+		83: y <= u1[0] ? s1 : s2;
 	endcase
 end
 
-- 
2.30.2