array compare (except = != nil) are illegal

R=r OCL=21637 CL=21637

array compare (except = != nil) are illegal
R=r OCL=21637 CL=21637
a91a0a6a · Ken Thompson · 6fa74e09 · a91a0a6a
Commit a91a0a6a authored Dec 19, 2008 by Ken Thompson
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cgen.c src/cmd/6g/cgen.c +5 -0

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--- a/src/cmd/6g/cgen.c
+++ b/src/cmd/6g/cgen.c
@@ -751,6 +751,11 @@ bgen(Node *n, int true, Prog *to)
 		}

 		if(isdarray(nl->type)) {
+			// only valid to cmp darray to literal nil
+			if((a != OEQ && a != ONE) || nr->op != OLITERAL) {
+				yyerror("illegal array comparison");
+				break;
+			}
 			a = optoas(a, types[tptr]);
 			regalloc(&n1, types[tptr], N);
 			agen(nl, &n1);