From dcc064fe941b17dad67a13cd635c76a04cde7a69 Mon Sep 17 00:00:00 2001
From: Ken Thompson <ken@golang.org>
Date: Thu, 18 Dec 2008 21:33:45 -0800
Subject: [PATCH] cmp [] to nil

R=r
OCL=21567
CL=21567
---
 src/cmd/6g/cgen.c  | 14 ++++++++++++++
 src/cmd/gc/const.c | 14 ++++++++++----
 src/cmd/gc/walk.c  |  4 ++++
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/src/cmd/6g/cgen.c b/src/cmd/6g/cgen.c
index e19fdd11b1..a56ba72236 100644
--- a/src/cmd/6g/cgen.c
+++ b/src/cmd/6g/cgen.c
@@ -750,6 +750,20 @@ bgen(Node *n, int true, Prog *to)
 			nr = r;
 		}
 
+		if(isdarray(nl->type)) {
+			a = optoas(a, types[tptr]);
+			regalloc(&n1, types[tptr], N);
+			agen(nl, &n1);
+			n2 = n1;
+			n2.op = OINDREG;
+			n2.xoffset = offsetof(Array,array);
+			nodconst(&tmp, types[tptr], 0);
+			gins(optoas(OCMP, types[tptr]), &n2, &tmp);
+			patch(gbranch(a, types[tptr]), to);
+			regfree(&n1);
+			break;
+		}
+
 		a = optoas(a, nr->type);
 
 		if(nr->ullman >= UINF) {
diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index b903d582d6..eefc277a0f 100644
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -63,11 +63,17 @@ convlit1(Node *n, Type *t, int conv)
 	case Wlitnil:
 		if(isptrto(t, TSTRING))
 			goto bad1;
-		if(isptr[et])
-			break;
-		if(et == TINTER)
+		switch(et) {
+		default:
+			goto bad1;
+
+		case TPTR32:
+		case TPTR64:
+		case TINTER:
+		case TARRAY:
 			break;
-		goto bad1;
+		}
+		break;
 
 	case Wlitstr:
 		if(isnilinter(t)) {
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 55fd025f3a..a8f988b049 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -1033,6 +1033,10 @@ loop:
 	case ONE:
 		if(n->left->type == T)
 			goto ret;
+		if(isdarray(n->left->type)) {
+			t = types[TBOOL];
+			break;
+		}
 		et = n->left->type->etype;
 		if(!okforeq[et])
 			goto badt;
-- 
2.48.1