cmd/compile: replace aindex with typArray

aindex is overkill when it's only ever used with known integer
constants, so just use typArray directly instead.

Change-Id: I43fc14e604172df859b3ad9d848d219bbe48e434
Reviewed-on: https://go-review.googlesource.com/30979
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/subr.go

@@ -475,30 +475,6 @@ func nodbool(b bool) *Node {
 	return c
 }
 
-func aindex(b *Node, t *Type) *Type {
-	hasbound := false
-	var bound int64
-	b = typecheck(b, Erv)
-	if b != nil {
-		switch consttype(b) {
-		default:
-			yyerror("array bound must be an integer expression")
-
-		case CTINT, CTRUNE:
-			hasbound = true
-			bound = b.Int64()
-			if bound < 0 {
-				yyerror("array bound must be non negative")
-			}
-		}
-	}
-
-	if !hasbound {
-		return typSlice(t)
-	}
-	return typArray(t, bound)
-}
-
 // treecopy recursively copies n, with the exception of
 // ONAME, OLITERAL, OTYPE, and non-iota ONONAME leaves.
 // Copies of iota ONONAME nodes are assigned the current

src/cmd/compile/internal/gc/walk.go

@@ -1547,7 +1547,7 @@ opswitch:
 			}
 			// var arr [r]T
 			// n = arr[:l]
-			t = aindex(r, t.Elem()) // [r]T
+			t = typArray(t.Elem(), nonnegintconst(r)) // [r]T
 			var_ := temp(t)
 			a := nod(OAS, var_, nil) // zero temp
 			a = typecheck(a, Etop)
@@ -1585,7 +1585,7 @@ opswitch:
 	case ORUNESTR:
 		a := nodnil()
 		if n.Esc == EscNone {
-			t := aindex(nodintconst(4), Types[TUINT8])
+			t := typArray(Types[TUINT8], 4)
 			var_ := temp(t)
 			a = nod(OADDR, var_, nil)
 		}
@@ -1597,7 +1597,7 @@ opswitch:
 		a := nodnil()
 		if n.Esc == EscNone {
 			// Create temporary buffer for string on stack.
-			t := aindex(nodintconst(tmpstringbufsize), Types[TUINT8])
+			t := typArray(Types[TUINT8], tmpstringbufsize)
 
 			a = nod(OADDR, temp(t), nil)
 		}
@@ -1623,7 +1623,7 @@ opswitch:
 
 		if n.Esc == EscNone {
 			// Create temporary buffer for string on stack.
-			t := aindex(nodintconst(tmpstringbufsize), Types[TUINT8])
+			t := typArray(Types[TUINT8], tmpstringbufsize)
 
 			a = nod(OADDR, temp(t), nil)
 		}
@@ -1636,7 +1636,7 @@ opswitch:
 
 		if n.Esc == EscNone {
 			// Create temporary buffer for slice on stack.
-			t := aindex(nodintconst(tmpstringbufsize), Types[TUINT8])
+			t := typArray(Types[TUINT8], tmpstringbufsize)
 
 			a = nod(OADDR, temp(t), nil)
 		}
@@ -1653,7 +1653,7 @@ opswitch:
 
 		if n.Esc == EscNone {
 			// Create temporary buffer for slice on stack.
-			t := aindex(nodintconst(tmpstringbufsize), Types[TINT32])
+			t := typArray(Types[TINT32], tmpstringbufsize)
 
 			a = nod(OADDR, temp(t), nil)
 		}
@@ -2840,7 +2840,7 @@ func addstr(n *Node, init *Nodes) *Node {
 		// Don't allocate the buffer if the result won't fit.
 		if sz < tmpstringbufsize {
 			// Create temporary buffer for result string on stack.
-			t := aindex(nodintconst(tmpstringbufsize), Types[TUINT8])
+			t := typArray(Types[TUINT8], tmpstringbufsize)
 
 			buf = nod(OADDR, temp(t), nil)
 		}