diff --git a/src/V3Assert.cpp b/src/V3Assert.cpp
index 76d166ed0..66b05e274 100644
--- a/src/V3Assert.cpp
+++ b/src/V3Assert.cpp
@@ -80,7 +80,7 @@ private:
 			  // This allows syntax errors and such to be detected normally.
 			  (v3Global.opt.assertOn()
 			   ? (AstNode*)(new AstCMath(nodep->fileline(), "Verilated::assertOn()", 1))
-			   : (AstNode*)(new AstConst(nodep->fileline(), V3Number(nodep->fileline(), 1, 0)))),
+			   : (AstNode*)(new AstConst(nodep->fileline(), AstConst::LogicFalse()))),
 			  nodep, NULL);
     }
 
@@ -91,8 +91,8 @@ private:
 			  // If assertions are off, have constant propagation rip them out later
 			  // This allows syntax errors and such to be detected normally.
 			  (v3Global.opt.coverage()
-			   ? (AstNode*)(new AstConst(nodep->fileline(), V3Number(nodep->fileline(), 1, 1)))
-			   : (AstNode*)(new AstConst(nodep->fileline(), V3Number(nodep->fileline(), 1, 0)))),
+			   ? (AstNode*)(new AstConst(nodep->fileline(), AstConst::LogicTrue()))
+			   : (AstNode*)(new AstConst(nodep->fileline(), AstConst::LogicFalse()))),
 			  nodep, NULL);
     }
 
diff --git a/src/V3AstNodes.h b/src/V3AstNodes.h
index 1fc1c22ec..d554fed05 100644
--- a/src/V3AstNodes.h
+++ b/src/V3AstNodes.h
@@ -59,6 +59,15 @@ public:
     AstConst(FileLine* fl, Unsized32, uint32_t num)  // Unsized 32-bit integer of specified value
 	:AstNodeMath(fl)
 	,m_num(V3Number(fl,32,num)) { m_num.width(32,false); width(32,m_num.minWidth()); }
+    class LogicFalse {};
+    AstConst(FileLine* fl, LogicFalse) // Shorthand const 0, know the dtype should be a logic of size 1
+	:AstNodeMath(fl)
+	,m_num(V3Number(fl,1,0)) { width(1,0); }
+    class LogicTrue {};
+    AstConst(FileLine* fl, LogicTrue) // Shorthand const 1, know the dtype should be a logic of size 1
+	:AstNodeMath(fl)
+	,m_num(V3Number(fl,1,1)) { width(1,0); }
+
     ASTNODE_NODE_FUNCS(Const, CONST)
     virtual string name()	const { return num().ascii(); }		// * = Value
     virtual const V3Number& num()	const { return m_num; }		// * = Value
diff --git a/src/V3Case.cpp b/src/V3Case.cpp
index 52d507148..db73d72f4 100644
--- a/src/V3Case.cpp
+++ b/src/V3Case.cpp
@@ -308,7 +308,7 @@ private:
 	for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
 	    if (!itemp->condsp()) {
 		// Default clause.  Just make true, we'll optimize it away later
-		itemp->condsp(new AstConst(itemp->fileline(), V3Number(itemp->fileline(), 1,1)));
+		itemp->condsp(new AstConst(itemp->fileline(), AstConst::LogicTrue()));
 		hadDefault = true;
 	    } else {
 		// Expressioned clause
@@ -326,8 +326,8 @@ private:
 			icondp->deleteTree(); icondp=NULL; iconstp=NULL;
 			// For simplicity, make expression that is not equal, and let later
 			// optimizations remove it
-			and1p = new AstConst(itemp->fileline(), V3Number(itemp->fileline(),1,0));
-			and2p = new AstConst(itemp->fileline(), V3Number(itemp->fileline(),1,1));
+			and1p = new AstConst(itemp->fileline(), AstConst::LogicFalse());
+			and2p = new AstConst(itemp->fileline(), AstConst::LogicTrue());
 		    } else if (iconstp && iconstp->num().isFourState()
 			       && (nodep->casex() || nodep->casez())) {
 			V3Number nummask (itemp->fileline(), iconstp->width());
@@ -361,7 +361,7 @@ private:
 	    // If there was no default, add a empty one, this greatly simplifies below code
 	    // and constant propagation will just eliminate it for us later.
 	    nodep->addItemsp(new AstCaseItem(nodep->fileline(),
-					     new AstConst(nodep->fileline(), V3Number(nodep->fileline(),1,1)),
+					     new AstConst(nodep->fileline(), AstConst::LogicTrue()),
 					     NULL));
 	}
 	if (debug()>=9) nodep->dumpTree(cout,"    _comp_COND: ");
@@ -398,7 +398,7 @@ private:
 		AstNode* itemexprp = ifexprp;  ifexprp=NULL;
 		if (depth == (CASE_ENCODER_GROUP_DEPTH)) { // End of group - can skip the condition
 		    itemexprp->deleteTree(); itemexprp=NULL;
-		    itemexprp = new AstConst(itemp->fileline(), V3Number(itemp->fileline(),1,1));
+		    itemexprp = new AstConst(itemp->fileline(), AstConst::LogicTrue());
 		}
 		AstIf* newp = new AstIf(itemp->fileline(), itemexprp, istmtsp, NULL);
 		if (itemnextp) itemnextp->addElsesp(newp);
diff --git a/src/V3Trace.cpp b/src/V3Trace.cpp
index 8ae59b2a5..9458b6590 100644
--- a/src/V3Trace.cpp
+++ b/src/V3Trace.cpp
@@ -330,7 +330,7 @@ private:
 					new AstSel (fl, new AstVarRef(fl, m_activityVscp, true),
 						    new AstConst(fl, acode),
 						    new AstConst(fl, 1)),
-					new AstConst (fl, V3Number(fl, 1, 1))));
+					new AstConst (fl, AstConst::LogicTrue())));
 		}
 	    }
 	}
diff --git a/src/verilog.y b/src/verilog.y
index 111dae5f6..c090ab505 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -1738,7 +1738,7 @@ statement_item<nodep>:		// IEEE: statement_item
 	//UNSUP	yP_MINUSGT hierarchical_identifier/*event*/ ';'	{ UNSUP }
 	//UNSUP	yP_MINUSGTGT delay_or_event_controlE hierarchical_identifier/*event*/ ';'	{ UNSUP }
 	//			// IEEE: loop_statement
-	|	yFOREVER stmtBlock			{ $$ = new AstWhile($1,new AstConst($1,V3Number($1,1,1)),$2); }
+	|	yFOREVER stmtBlock			{ $$ = new AstWhile($1,new AstConst($1,AstConst::LogicTrue()),$2); }
 	|	yREPEAT '(' expr ')' stmtBlock		{ $$ = new AstRepeat($1,$3,$5);}
 	|	yWHILE '(' expr ')' stmtBlock		{ $$ = new AstWhile($1,$3,$5);}
 	//			// for's first ';' is in for_initalization
@@ -2816,7 +2816,7 @@ pslSere<nodep>:
 // This can be bypassed with the _(...) embedding of any arbitrary expression.
 pslExpr<nodep>:
 		exprPsl					{ $$ = new AstPslBool($1->fileline(), $1); }
-	|	yTRUE					{ $$ = new AstPslBool($1, new AstConst($1, V3Number($1,1,1))); }
+	|	yTRUE					{ $$ = new AstPslBool($1, new AstConst($1, AstConst::LogicTrue())); }
 	;
 
 //**********************************************************************