fix float <-> int64 conversions

R=rsc
APPROVED=rsc
DELTA=25  (25 added, 0 deleted, 0 changed)
OCL=35566
CL=35574

src/cmd/gc/sys.go

@@ -89,3 +89,5 @@ func int64div(int64, int64) int64
 func uint64div(uint64, uint64) uint64
 func int64mod(int64, int64) int64
 func uint64mod(uint64, uint64) uint64
+func float64toint64(float64) int64
+func int64tofloat64(int64) float64

src/cmd/gc/walk.c

@@ -713,6 +713,16 @@ walkexpr(Node **np, NodeList **init)
 
 	case OCONV:
 	case OCONVNOP:
+		if(thechar == '5') {
+			if(isfloat[n->left->type->etype] && (n->type->etype == TINT64)) {
+				n = mkcall("float64toint64", n->type, init, conv(n->left, types[TFLOAT64]));
+				goto ret;
+			}
+			if((n->left->type->etype == TINT64) && isfloat[n->type->etype]) {
+				n = mkcall("int64tofloat64", n->type, init, conv(n->left, types[TINT64]));
+				goto ret;
+			}
+		}
 		walkexpr(&n->left, init);
 		goto ret;
 

src/pkg/runtime/arm/vlrt.c

@@ -142,6 +142,12 @@ _f2v(Vlong *y, float f)
         _d2v(y, f);
 }
 
+void
+sys·float64toint64(double d, Vlong y)
+{
+	_d2v(&y, d);
+}
+
 double
 _v2d(Vlong x)
 {
@@ -162,6 +168,13 @@ _v2f(Vlong x)
         return _v2d(x);
 }
 
+void
+sys·int64tofloat64(Vlong y, double d)
+{
+	d = _v2d(y);
+}
+
+
 static void
 dodiv(Vlong num, Vlong den, Vlong *q, Vlong *r)
 {