JS: improve compression of and/or expressions

tdewolff · Apr 8, 2022 · ef36774 · ef36774
1 parent 09c93b1
commit ef36774
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Showing 2 changed files with 86 additions and 44 deletions.
diff --git a/js/js_test.go b/js/js_test.go
@@ -259,7 +259,7 @@ func TestJS(t *testing.T) {
 		{`if(a,b)b`, `a,b&&b`},
 		{`if(a,b)b;else d`, `a,b||d`},
 		{`if(a=b)a;else b`, `(a=b)||b`},
-		{`if(!a&&!b){return true}else if(!a||!b){return false}return c&&d`, `return!a&&!b||!(!a||!b)&&c&&d`},
+		{`if(!a&&!b){return true}else if(!a||!b){return false}return c&&d`, `return!a&&!b||!!a&&!!b&&c&&d`},
 		{`if(!a){if(b){throw c}else{return c}}else{return a}`, `if(a)return a;if(b)throw c;return c`},
 		{`if(!a){return y}else if(b){if(c){return x}}return z`, `return a?b&&c?x:z:y`},
 
@@ -545,7 +545,7 @@ func TestJS(t *testing.T) {
 		{`a?!0:!1`, `!!a`},
 		{`a?0:1`, `a?0:1`},
 		{`!!a?0:1`, `!!a?0:1`},
-		//{`a&&b?!1:!0`, `!a||!b`}, // TODO
+		{`a&&b?!1:!0`, `!a||!b`},
 		{`a&&b?!0:!1`, `!!(a&&b)`},
 		{`a?true:5`, `!!a||5`},
 		{`a?5:false`, `!!a&&5`},
@@ -600,13 +600,15 @@ func TestJS(t *testing.T) {
 		{`a??=b`, `a??=b`},
 		{`a==false`, `a==!1`},
 		{`a===false`, `a===!1`},
-		//{`!(a||b)`, `!a&&!b`}, // TODO
-		//{`!(a&&b)`, `!a||!b`}, // TODO
-		//{`!(!a||!b)`, `a&&b`},  // we don't know of a or b are booleans
-		//{`!(!a&&!b)`, `a||b`},
-		//{`!(!a&&b)&&c`, `(a||!b)&&c`},
+		{`!(a||b)`, `!a&&!b`},
+		{`!(a&&b)`, `!a||!b`},
 		{`!(a&&b)&&c`, `!(a&&b)&&c`},
-		//{`a===false||b===true?false:true`, `a!==!1&&b!==!0`}, // TODO
+		{`c&&!(a&&b===5)`, `c&&!(a&&b===5)`},
+		{`c&&!(!a&&b!==5)`, `c&&!(!a&&b!==5)`},
+		{`c&&!(a==3&&b!==5)`, `c&&(a!=3||b===5)`},
+		{`!(a>=0&&a<=1||a>=2&&a<=3)`, `!(a>=0&&a<=1||a>=2&&a<=3)`},
+		{`a===false||b===true?false:true`, `a!==!1&&b!==!0`},
+		//{`!(!(a>=0||a<=1)&&!(a>=2||a<=3))`, `!!(a>=0||a<=1||a>=2||a<=3)`}, // TODO
 
 		// other
 		{`async function g(){await x+y}`, `async function g(){await x+y}`},

diff --git a/js/util.go b/js/util.go
@@ -591,44 +591,84 @@ func optimizeBooleanExpr(expr js.IExpr, invert bool, prec js.OpPrec) js.IExpr {
 }
 
 func optimizeUnaryExpr(expr *js.UnaryExpr, prec js.OpPrec) js.IExpr {
-	//if group, ok := expr.X.(*js.GroupExpr); ok && expr.Op == js.NotToken {
-	//	if binary, ok := group.X.(*js.BinaryExpr); ok && (binary.Op == js.AndToken || binary.Op == js.OrToken) {
-	//		op := js.AndToken
-	//		if binary.Op == js.AndToken {
-	//			op = js.OrToken
-	//		}
-	//		precInside := binaryOpPrecMap[op]
+	return expr
+	if group, ok := expr.X.(*js.GroupExpr); ok && expr.Op == js.NotToken {
+		if binary, ok := group.X.(*js.BinaryExpr); ok && (binary.Op == js.AndToken || binary.Op == js.OrToken) {
+			op := js.AndToken
+			if binary.Op == js.AndToken {
+				op = js.OrToken
+			}
+			precInside := binaryOpPrecMap[op]
+			needsGroup := precInside < prec && (precInside != js.OpCoalesce || prec != js.OpBitOr)
+
+			// rewrite !(a||b) to !a&&!b
+			// rewrite !(a==0||b==0) to a!=0&&b!=0
+			score := 3 // savings if rewritten (group parentheses and not-token)
+			if needsGroup {
+				score -= 2
+			}
+			score -= 2 // add two not-tokens for left and right
 
-	//		// rewrite !(a||b) to !a&&!b
-	//		// rewrite !(a==0||b==0) to a!=0&&b!=0
-	//		var isNotX, isNotY, isEqX, isEqY bool
-	//		if unaryExpr, ok := binary.X.(*js.UnaryExpr); ok {
-	//			isNotX = unaryExpr.Op == js.NotToken
-	//		} else if binaryExpr, ok := binary.X.(*js.BinaryExpr); ok {
-	//			isEqX = binaryOpPrecMap[binaryExpr.Op] == js.OpEquals
-	//		}
-	//		if unaryExpr, ok := binary.Y.(*js.UnaryExpr); ok {
-	//			isNotY = unaryExpr.Op == js.NotToken
-	//		} else if binaryExpr, ok := binary.Y.(*js.BinaryExpr); ok {
-	//			isEqY = binaryOpPrecMap[binaryExpr.Op] == js.OpEquals
-	//		}
-	//		if !isNotX && !isNotY && (isEqX || isEqY || (prec <= precInside || precInside == js.OpCoalesce && prec == js.OpBitOr)) {
-	//			binary.Op = op
-	//			if isEqX {
-	//				binary.X.(*js.BinaryExpr).Op = invertBooleanOp(binary.X.(*js.BinaryExpr).Op)
-	//			} else {
-	//				binary.X = &js.UnaryExpr{js.NotToken, binary.X}
-	//			}
-	//			if isEqY {
+			// == and === can become != and !==
+			var isEqX, isEqY bool
+			if binaryExpr, ok := binary.X.(*js.BinaryExpr); ok && binaryOpPrecMap[binaryExpr.Op] == js.OpEquals {
+				score += 1
+				isEqX = true
+			}
+			if binaryExpr, ok := binary.Y.(*js.BinaryExpr); ok && binaryOpPrecMap[binaryExpr.Op] == js.OpEquals {
+				score += 1
+				isEqY = true
+			}
 
-	//				binary.Y.(*js.BinaryExpr).Op = invertBooleanOp(binary.Y.(*js.BinaryExpr).Op)
-	//			} else {
-	//				binary.Y = &js.UnaryExpr{js.NotToken, binary.Y}
-	//			}
-	//			return binary
-	//		}
-	//	}
-	//}
+			// left and right may need group or can remove group
+			var needsGroupX, needsGroupY bool
+			if op == js.OrToken {
+				// remove group
+				if exprPrec(binary.X) == js.OpOr {
+					score += 2
+				}
+				if exprPrec(binary.Y) == js.OpAnd {
+					score += 2
+				}
+			} else {
+				// add group
+				if !isEqX && exprPrec(binary.X) < js.OpUnary {
+					score -= 2
+					needsGroupX = true
+				}
+				if !isEqY && exprPrec(binary.Y) < js.OpUnary {
+					score -= 2
+					needsGroupY = true
+				}
+			}
+
+			if 0 < score {
+				binary.Op = op
+				if isEqX {
+					binary.X.(*js.BinaryExpr).Op = invertBooleanOp(binary.X.(*js.BinaryExpr).Op)
+				}
+				if isEqY {
+					binary.Y.(*js.BinaryExpr).Op = invertBooleanOp(binary.Y.(*js.BinaryExpr).Op)
+				}
+				if needsGroupX {
+					binary.X = &js.GroupExpr{binary.X}
+				}
+				if needsGroupY {
+					binary.Y = &js.GroupExpr{binary.Y}
+				}
+				if !isEqX {
+					binary.X = &js.UnaryExpr{js.NotToken, binary.X}
+				}
+				if !isEqY {
+					binary.Y = &js.UnaryExpr{js.NotToken, binary.Y}
+				}
+				if needsGroup {
+					return &js.GroupExpr{binary}
+				}
+				return binary
+			}
+		}
+	}
 	return expr
 }