Re: [9front] Start Syncing Compilers with Plan 9

[cinap_lenrek@felloff.net]

ok, i tried the OINDEX change in a vm and ran into the issue
that 8c then runs out of registers compiling a chain of []
operations (libvorbis).

the reason is the following code in xcom(), which converts
addition with indirect operands into a index operation.
having side() return 1 for OINDE gated that bug.

the issue is that when the index operand is a name or
constant, its complex number (#reg) is zero which we
would propagate to the INDEX operation itself. but we
need at least ONE index register!

adjusting the #reg at just like at the brk: in xcom() fixes
the issue.

		if(n->addable == 8 && !side(n)) {
			indx(n);
			l = new1(OINDEX, idx.basetree, idx.regtree);
			l->scale = idx.scale;
			l->addable = 9;
			l->complex = l->right->complex;
+			if(l->complex == 0)
+				l->complex++;
			l->type = l->left->type;
			n->op = OADDR;
			n->left = l;
			n->right = Z;
			n->addable = 8;
			break;
		}

commited in:

changeset:   7276:0e16ecb295ad
parent:      7272:648786a6af71
user:        cinap_lenrek@felloff.net
date:        Tue Jun 18 13:28:15 2019 +0200
summary:     8c, 6c: fix INDEX node #reg calculation

--
cinap