handle properly booleans from v, ok

Change-Id: Ibb6e978384c84b2894dabb2319f8121aab27cac1

Author: mateusz834

src/cmd/compile/internal/devirtualize/devirtualize.go

@@ -343,10 +343,23 @@ func analyzeAssignments(n ir.Node, analyzed map[*ir.Name]*types.Type) *types.Typ
 			}
 		case ir.OAS2DOTTYPE:
 			n := n.(*ir.AssignListStmt)
-			for _, p := range n.Lhs {
-				if isName(p) {
-					return handleNode(ir.OAS2DOTTYPE, n.Rhs[0])
-				}
+			if isName(n.Lhs[0]) {
+				return handleNode(ir.OAS2DOTTYPE, n.Rhs[0])
+			}
+			if isName(n.Lhs[1]) {
+				// boolean, nothing to devirtualize.
+				typ = nil
+				return true
+			}
+		case ir.OAS2MAPR, ir.OAS2RECV, ir.OSELRECV2:
+			n := n.(*ir.AssignListStmt)
+			if isName(n.Lhs[0]) {
+				return handleType(n.Op(), n.Pos(), n.Rhs[0].Type())
+			}
+			if isName(n.Lhs[1]) {
+				// boolean, nothing to devirtualize.
+				typ = nil
+				return true
 			}
 		case ir.OAS2FUNC:
 			n := n.(*ir.AssignListStmt)
@@ -368,13 +381,6 @@ func analyzeAssignments(n ir.Node, analyzed map[*ir.Name]*types.Type) *types.Typ
 					return true
 				}
 			}
-		case ir.OAS2MAPR, ir.OAS2RECV, ir.OSELRECV2:
-			n := n.(*ir.AssignListStmt)
-			for _, p := range n.Lhs {
-				if isName(p) {
-					return handleType(n.Op(), n.Pos(), n.Rhs[0].Type())
-				}
-			}
 		case ir.ORANGE:
 			n := n.(*ir.RangeStmt)
 			xTyp := n.X.Type()

test/devirtualization.go

@@ -1043,6 +1043,35 @@ func selfAssigns() {
 	}
 }
 
+func boolNoDevirt() {
+	{
+		m := make(map[int]*Impl) // ERROR "does not escape"
+		var v any = &Impl{}      // ERROR "escapes"
+		_, v = m[0]              // ERROR "escapes"
+		v.(A).A()
+	}
+	{
+		m := make(chan *Impl)
+		var v any = &Impl{} // ERROR "escapes"
+		select {
+		case _, v = <-m: // ERROR "escapes"
+		}
+		v.(A).A()
+	}
+	{
+		m := make(chan *Impl)
+		var v any = &Impl{} // ERROR "escapes"
+		_, v = <-m          // ERROR "escapes"
+		v.(A).A()
+	}
+	{
+		var a any = 4       // ERROR "does not escape"
+		var v any = &Impl{} // ERROR "escapes"
+		_, v = a.(int)      // ERROR "escapes"
+		v.(A).A()
+	}
+}
+
 func addrTaken() {
 	{
 		var a A = &Impl{} // ERROR "escapes"