cmd/compile: implement range over integer

[gostls13.git] / src / cmd / compile / internal / walk / range.go

diff --git a/src/cmd/compile/internal/walk/range.go b/src/cmd/compile/internal/walk/range.go
index 4e9908b5d1ae4a3275193d33eb1c2d91a70a13cf..93898b3a66f296a715ddd89e5fdf75a672a86df9 100644 (file)
--- a/src/cmd/compile/internal/walk/range.go
+++ b/src/cmd/compile/internal/walk/range.go
@@ -74,11 +74,25 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 
        var body []ir.Node
        var init []ir.Node
-       switch t.Kind() {
+       switch k := t.Kind(); {
        default:
                base.Fatalf("walkRange")
 
-       case types.TARRAY, types.TSLICE, types.TPTR: // TPTR is pointer-to-array
+       case types.IsInt[k]:
+               hv1 := typecheck.TempAt(base.Pos, ir.CurFunc, t)
+               hn := typecheck.TempAt(base.Pos, ir.CurFunc, t)
+
+               init = append(init, ir.NewAssignStmt(base.Pos, hv1, nil))
+               init = append(init, ir.NewAssignStmt(base.Pos, hn, a))
+
+               nfor.Cond = ir.NewBinaryExpr(base.Pos, ir.OLT, hv1, hn)
+               nfor.Post = ir.NewAssignStmt(base.Pos, hv1, ir.NewBinaryExpr(base.Pos, ir.OADD, hv1, ir.NewInt(base.Pos, 1)))
+
+               if v1 != nil {
+                       body = []ir.Node{rangeAssign(nrange, hv1)}
+               }
+
+       case k == types.TARRAY, k == types.TSLICE, k == types.TPTR: // TPTR is pointer-to-array
                if nn := arrayRangeClear(nrange, v1, v2, a); nn != nil {
                        base.Pos = lno
                        return nn
@@ -219,7 +233,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
                as := ir.NewAssignStmt(base.Pos, hu, ir.NewBinaryExpr(base.Pos, ir.OADD, huVal, ir.NewInt(base.Pos, elem.Size())))
                nfor.Post = ir.NewBlockStmt(base.Pos, []ir.Node{nfor.Post, as})
 
-       case types.TMAP:
+       case k == types.TMAP:
                // order.stmt allocated the iterator for us.
                // we only use a once, so no copy needed.
                ha := a
@@ -248,7 +262,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
                        body = []ir.Node{rangeAssign2(nrange, key, elem)}
                }
 
-       case types.TCHAN:
+       case k == types.TCHAN:
                // order.stmt arranged for a copy of the channel variable.
                ha := a
 
@@ -275,7 +289,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
                // See issue 15281.
                body = append(body, ir.NewAssignStmt(base.Pos, hv1, nil))
 
-       case types.TSTRING:
+       case k == types.TSTRING:
                // Transform string range statements like "for v1, v2 = range a" into
                //
                // ha := a