8g: discard tempalloc/tempfree experiment

in favor of tempname.
allows optimizer to do more.
unfortunately, optimizer seems to be broken; disable it.

R=ken2
https://golang.org/cl/163091

src/cmd/8g/cgen.c

@@ -10,18 +10,16 @@
 void
 mgen(Node *n, Node *n1, Node *rg)
 {
-	n1->ostk = 0;
 	n1->op = OEMPTY;
 
 	if(n->addable) {
 		*n1 = *n;
-		n1->ostk = 0;
 		if(n1->op == OREGISTER || n1->op == OINDREG)
 			reg[n->val.u.reg]++;
 		return;
 	}
 	if(n->type->width > widthptr)
-		tempalloc(n1, n->type);
+		tempname(n1, n->type);
 	else
 		regalloc(n1, n->type, rg);
 	cgen(n, n1);
@@ -30,9 +28,7 @@ mgen(Node *n, Node *n1, Node *rg)
 void
 mfree(Node *n)
 {
-	if(n->ostk)
-		tempfree(n);
-	else if(n->op == OREGISTER)
+	if(n->op == OREGISTER)
 		regfree(n);
 }
 
@@ -70,10 +66,9 @@ cgen(Node *n, Node *res)
 
 	// function calls on both sides?  introduce temporary
 	if(n->ullman >= UINF && res->ullman >= UINF) {
-		tempalloc(&n1, n->type);
+		tempname(&n1, n->type);
 		cgen(n, &n1);
 		cgen(&n1, res);
-		tempfree(&n1);
 		return;
 	}
 
@@ -107,10 +102,9 @@ cgen(Node *n, Node *res)
 	if(!n->addable && !res->addable) {
 		// could use regalloc here sometimes,
 		// but have to check for ullman >= UINF.
-		tempalloc(&n1, n->type);
+		tempname(&n1, n->type);
 		cgen(n, &n1);
 		cgen(&n1, res);
-		tempfree(&n1);
 		return;
 	}
 
@@ -132,12 +126,11 @@ cgen(Node *n, Node *res)
 	if(nl != N && nl->ullman >= UINF)
 	if(nr != N && nr->ullman >= UINF) {
 		// both are hard
-		tempalloc(&n1, nl->type);
+		tempname(&n1, nl->type);
 		cgen(nl, &n1);
 		n2 = *n;
 		n2.left = &n1;
 		cgen(&n2, res);
-		tempfree(&n1);
 		return;
 	}
 
@@ -240,11 +233,10 @@ cgen(Node *n, Node *res)
 		if(istype(nl->type, TMAP) || istype(nl->type, TCHAN)) {
 			// map has len in the first 32-bit word.
 			// a zero pointer means zero length
-			tempalloc(&n1, types[tptr]);
+			tempname(&n1, types[tptr]);
 			cgen(nl, &n1);
 			regalloc(&n2, types[tptr], N);
 			gmove(&n1, &n2);
-			tempfree(&n1);
 			n1 = n2;
 
 			nodconst(&n2, types[tptr], 0);
@@ -354,7 +346,7 @@ sbop:	// symmetric binary
 
 abop:	// asymmetric binary
 	if(nl->ullman >= nr->ullman) {
-		tempalloc(&nt, nl->type);
+		tempname(&nt, nl->type);
 		cgen(nl, &nt);
 		mgen(nr, &n2, N);
 		regalloc(&n1, nl->type, res);
@@ -363,7 +355,6 @@ abop:	// asymmetric binary
 		gmove(&n1, res);
 		regfree(&n1);
 		mfree(&n2);
-		tempfree(&nt);
 	} else {
 		regalloc(&n2, nr->type, res);
 		cgen(nr, &n2);
@@ -377,11 +368,10 @@ abop:	// asymmetric binary
 	return;
 
 uop:	// unary
-	tempalloc(&n1, nl->type);
+	tempname(&n1, nl->type);
 	cgen(nl, &n1);
 	gins(a, N, &n1);
 	gmove(&n1, res);
-	tempfree(&n1);
 	return;
 
 flt:	// floating-point.  387 (not SSE2) to interoperate with 6c
@@ -490,30 +480,27 @@ agen(Node *n, Node *res)
 		if(nr->addable) {
 			agenr(nl, &n3, res);
 			if(!isconst(nr, CTINT)) {
-				tempalloc(&tmp, types[TINT32]);
+				tempname(&tmp, types[TINT32]);
 				cgen(nr, &tmp);
 				regalloc(&n1, tmp.type, N);
 				gmove(&tmp, &n1);
-				tempfree(&tmp);
 			}
 		} else if(nl->addable) {
 			if(!isconst(nr, CTINT)) {
-				tempalloc(&tmp, types[TINT32]);
+				tempname(&tmp, types[TINT32]);
 				cgen(nr, &tmp);
 				regalloc(&n1, tmp.type, N);
 				gmove(&tmp, &n1);
-				tempfree(&tmp);
 			}
 			regalloc(&n3, types[tptr], res);
 			agen(nl, &n3);
 		} else {
-			tempalloc(&tmp, types[TINT32]);
+			tempname(&tmp, types[TINT32]);
 			cgen(nr, &tmp);
 			nr = &tmp;
 			agenr(nl, &n3, res);
 			regalloc(&n1, tmp.type, N);
 			gins(optoas(OAS, tmp.type), &tmp, &n1);
-			tempfree(&tmp);
 		}
 
 		// &a is in &n3 (allocated in res)
@@ -693,11 +680,10 @@ igen(Node *n, Node *a, Node *res)
 {
 	Node n1;
 
-	tempalloc(&n1, types[tptr]);
+	tempname(&n1, types[tptr]);
 	agen(n, &n1);
 	regalloc(a, types[tptr], res);
 	gmove(&n1, a);
-	tempfree(&n1);
 	a->op = OINDREG;
 	a->type = n->type;
 }
@@ -713,11 +699,10 @@ agenr(Node *n, Node *a, Node *res)
 {
 	Node n1;
 
-	tempalloc(&n1, types[tptr]);
+	tempname(&n1, types[tptr]);
 	agen(n, &n1);
 	regalloc(a, types[tptr], res);
 	gmove(&n1, a);
-	tempfree(&n1);
 }
 
 /*
@@ -925,14 +910,12 @@ bgen(Node *n, int true, Prog *to)
 				// all the other ops have the same problem.
 				// We need to figure out what the right general
 				// solution is, besides telling people to use float64.
-				tempalloc(&t1, types[TFLOAT32]);
-				tempalloc(&t2, types[TFLOAT32]);
+				tempname(&t1, types[TFLOAT32]);
+				tempname(&t2, types[TFLOAT32]);
 				cgen(nr, &t1);
 				cgen(nl, &t2);
 				gmove(&t2, &tmp);
 				gins(AFCOMFP, &t1, &tmp);
-				tempfree(&t2);
-				tempfree(&t1);
 			}
 			gins(AFSTSW, N, &ax);
 			gins(ASAHF, N, N);
@@ -954,57 +937,49 @@ bgen(Node *n, int true, Prog *to)
 
 		if(is64(nr->type)) {
 			if(!nl->addable) {
-				tempalloc(&n1, nl->type);
+				tempname(&n1, nl->type);
 				cgen(nl, &n1);
 				nl = &n1;
 			}
 			if(!nr->addable) {
-				tempalloc(&n2, nr->type);
+				tempname(&n2, nr->type);
 				cgen(nr, &n2);
 				nr = &n2;
 			}
 			cmp64(nl, nr, a, to);
-			if(nr == &n2)
-				tempfree(&n2);
-			if(nl == &n1)
-				tempfree(&n1);
 			break;
 		}
 
 		a = optoas(a, nr->type);
 
 		if(nr->ullman >= UINF) {
-			tempalloc(&n1, nl->type);
-			tempalloc(&tmp, nr->type);
+			tempname(&n1, nl->type);
+			tempname(&tmp, nr->type);
 			cgen(nr, &tmp);
 			cgen(nl, &n1);
 			regalloc(&n2, nr->type, N);
 			cgen(&tmp, &n2);
-			tempfree(&tmp);
 			goto cmp;
 		}
 
-		tempalloc(&n1, nl->type);
+		tempname(&n1, nl->type);
 		cgen(nl, &n1);
 
 		if(smallintconst(nr)) {
 			gins(optoas(OCMP, nr->type), &n1, nr);
 			patch(gbranch(a, nr->type), to);
-			tempfree(&n1);
 			break;
 		}
 
-		tempalloc(&tmp, nr->type);
+		tempname(&tmp, nr->type);
 		cgen(nr, &tmp);
 		regalloc(&n2, nr->type, N);
 		gmove(&tmp, &n2);
-		tempfree(&tmp);
 
 cmp:
 		gins(optoas(OCMP, nr->type), &n1, &n2);
 		patch(gbranch(a, nr->type), to);
 		regfree(&n2);
-		tempfree(&n1);
 		break;
 	}
 }
@@ -1073,8 +1048,8 @@ sgen(Node *n, Node *res, int32 w)
 	nodreg(&dst, types[tptr], D_DI);
 	nodreg(&src, types[tptr], D_SI);
 
-	tempalloc(&tsrc, types[tptr]);
-	tempalloc(&tdst, types[tptr]);
+	tempname(&tsrc, types[tptr]);
+	tempname(&tdst, types[tptr]);
 	if(!n->addable)
 		agen(n, &tsrc);
 	if(!res->addable)
@@ -1087,8 +1062,6 @@ sgen(Node *n, Node *res, int32 w)
 		agen(res, &dst);
 	else
 		gmove(&tdst, &dst);
-	tempfree(&tdst);
-	tempfree(&tsrc);
 
 	c = w % 4;	// bytes
 	q = w / 4;	// doublewords

src/cmd/8g/cgen64.c

@@ -60,12 +60,12 @@ cgen64(Node *n, Node *res)
 	l = n->left;
 	r = n->right;
 	if(!l->addable) {
-		tempalloc(&t1, l->type);
+		tempname(&t1, l->type);
 		cgen(l, &t1);
 		l = &t1;
 	}
 	if(r != N && !r->addable) {
-		tempalloc(&t2, r->type);
+		tempname(&t2, r->type);
 		cgen(r, &t2);
 		r = &t2;
 	}
@@ -417,11 +417,7 @@ cgen64(Node *n, Node *res)
 	gins(AMOVL, &dx, &hi1);
 	splitclean();
 
-out:
-	if(r == &t2)
-		tempfree(&t2);
-	if(l == &t1)
-		tempfree(&t1);
+out:;
 }
 
 /*

src/cmd/8g/gg.h

@@ -137,8 +137,6 @@ void	ginit(void);
 void	gclean(void);
 void	regalloc(Node*, Type*, Node*);
 void	regfree(Node*);
-void	tempalloc(Node*, Type*);
-void	tempfree(Node*);
 Node*	nodarg(Type*, int);
 void	nodreg(Node*, Type*, int);
 void	nodindreg(Node*, Type*, int);

src/cmd/8g/ggen.c

@@ -80,6 +80,7 @@ compile(Node *fn)
 	pc->as = ARET;	// overwrite AEND
 	pc->lineno = lineno;
 
+if(0)
 	if(!debug['N'] || debug['R'] || debug['P']) {
 		regopt(ptxt);
 	}
@@ -198,7 +199,7 @@ cgen_callinter(Node *n, Node *res, int proc)
 	i = i->left;		// interface
 
 	if(!i->addable) {
-		tempalloc(&tmpi, i->type);
+		tempname(&tmpi, i->type);
 		cgen(i, &tmpi);
 		i = &tmpi;
 	}
@@ -230,9 +231,6 @@ cgen_callinter(Node *n, Node *res, int proc)
 	regfree(&nodr);
 	regfree(&nodo);
 
-	if(i == &tmpi)
-		tempfree(i);
-
 	setmaxarg(n->left->type);
 }
 
@@ -254,7 +252,7 @@ cgen_call(Node *n, int proc)
 	if(n->left->ullman >= UINF) {
 		// if name involves a fn call
 		// precompute the address of the fn
-		tempalloc(&afun, types[tptr]);
+		tempname(&afun, types[tptr]);
 		cgen(n->left, &afun);
 	}
 
@@ -267,7 +265,6 @@ cgen_call(Node *n, int proc)
 	if(n->left->ullman >= UINF) {
 		regalloc(&nod, types[tptr], N);
 		cgen_as(&nod, &afun);
-		tempfree(&afun);
 		nod.type = t;
 		ginscall(&nod, proc);
 		regfree(&nod);
@@ -385,12 +382,11 @@ cgen_asop(Node *n)
 	nr = n->right;
 
 	if(nr->ullman >= UINF && nl->ullman >= UINF) {
-		tempalloc(&n1, nr->type);
+		tempname(&n1, nr->type);
 		cgen(nr, &n1);
 		n2 = *n;
 		n2.right = &n1;
 		cgen_asop(&n2);
-		tempfree(&n1);
 		goto ret;
 	}
 
@@ -475,12 +471,12 @@ cgen_asop(Node *n)
 
 hard:
 	if(nr->ullman > nl->ullman) {
-		tempalloc(&n2, nr->type);
+		tempname(&n2, nr->type);
 		cgen(nr, &n2);
 		igen(nl, &n1, N);
 	} else {
 		igen(nl, &n1, N);
-		tempalloc(&n2, nr->type);
+		tempname(&n2, nr->type);
 		cgen(nr, &n2);
 	}
 
@@ -489,13 +485,11 @@ hard:
 	n3.right = &n2;
 	n3.op = n->etype;
 
-	tempalloc(&n4, nl->type);
+	tempname(&n4, nl->type);
 	cgen(&n3, &n4);
 	gmove(&n4, &n1);
 
 	regfree(&n1);
-	tempfree(&n4);
-	tempfree(&n2);
 
 ret:
 	;
@@ -528,8 +522,8 @@ dodiv(int op, Type *t, Node *nl, Node *nr, Node *res, Node *ax, Node *dx)
 {
 	Node n1, t1, t2, nz;
 
-	tempalloc(&t1, nl->type);
-	tempalloc(&t2, nr->type);
+	tempname(&t1, nl->type);
+	tempname(&t2, nr->type);
 	cgen(nl, &t1);
 	cgen(nr, &t2);
 
@@ -546,8 +540,6 @@ dodiv(int op, Type *t, Node *nl, Node *nr, Node *res, Node *ax, Node *dx)
 		gins(optoas(OEXTEND, t), N, N);
 	gins(optoas(op, t), &n1, N);
 	regfree(&n1);
-	tempfree(&t2);
-	tempfree(&t1);
 
 	if(op == ODIV)
 		gmove(ax, res);
@@ -567,7 +559,7 @@ savex(int dr, Node *x, Node *oldx, Node *res, Type *t)
 	// and not the destination
 	memset(oldx, 0, sizeof *oldx);
 	if(r > 0 && !samereg(x, res)) {
-		tempalloc(oldx, types[TINT32]);
+		tempname(oldx, types[TINT32]);
 		gmove(x, oldx);
 	}
 
@@ -582,7 +574,6 @@ restx(Node *x, Node *oldx)
 	if(oldx->op != 0) {
 		x->type = types[TINT32];
 		gmove(oldx, x);
-		tempfree(oldx);
 	}
 }
 
@@ -653,7 +644,7 @@ cgen_shift(int op, Node *nl, Node *nr, Node *res)
 	memset(&oldcx, 0, sizeof oldcx);
 	nodreg(&cx, types[TUINT32], D_CX);
 	if(reg[D_CX] > 1 && !samereg(&cx, res)) {
-		tempalloc(&oldcx, types[TUINT32]);
+		tempname(&oldcx, types[TUINT32]);
 		gmove(&cx, &oldcx);
 	}
 
@@ -683,10 +674,8 @@ cgen_shift(int op, Node *nl, Node *nr, Node *res)
 	patch(p1, pc);
 	gins(a, &n1, &n2);
 
-	if(oldcx.op != 0) {
+	if(oldcx.op != 0)
 		gmove(&oldcx, &cx);
-		tempfree(&oldcx);
-	}
 
 	gmove(&n2, res);
 
@@ -971,7 +960,7 @@ sliceslice:
 		if(bad)
 			goto no;
 
-		tempalloc(&ntemp, res->type);
+		tempname(&ntemp, res->type);
 		if(!sleasy(&nodes[0])) {
 			cgen(&nodes[0], &ntemp);
 			nnode0 = ntemp;
@@ -1079,8 +1068,6 @@ sliceslice:
 	if(!sleasy(res)) {
 		cgen(&nres, res);
 	}
-	if(ntemp.op != OXXX)
-		tempfree(&ntemp);
 	return 1;
 
 no:

src/cmd/8g/gsubr.c

@@ -793,42 +793,6 @@ regfree(Node *n)
 		fatal("regfree %R", i);
 }
 
-void
-tempalloc(Node *n, Type *t)
-{
-	int w;
-
-	dowidth(t);
-
-	memset(n, 0, sizeof(*n));
-	n->op = ONAME;
-	n->sym = S;
-	n->type = t;
-	n->etype = t->etype;
-	n->class = PAUTO;
-	n->addable = 1;
-	n->ullman = 1;
-	n->noescape = 1;
-	n->ostk = stksize;
-
-	w = t->width;
-	stksize += w;
-	stksize = rnd(stksize, w);
-	n->xoffset = -stksize;
-//print("tempalloc %d -> %d from %p\n", n->ostk, n->xoffset, __builtin_return_address(0));
-	if(stksize > maxstksize)
-		maxstksize = stksize;
-}
-
-void
-tempfree(Node *n)
-{
-//print("tempfree %d\n", n->xoffset);
-	if(n->xoffset != -stksize)
-		fatal("tempfree %lld %d", -n->xoffset, stksize);
-	stksize = n->ostk;
-}
-
 /*
  * initialize n to be register r of type t.
  */
@@ -1072,6 +1036,15 @@ bignodes(void)
 	mpmovecflt(zerof.val.u.fval, 0);
 }
 
+void
+memname(Node *n, Type *t)
+{
+	tempname(n, t);
+	strcpy(namebuf, n->sym->name);
+	namebuf[0] = '.';	// keep optimizer from registerizing
+	n->sym = lookup(namebuf);
+}
+
 void
 gmove(Node *f, Node *t)
 {
@@ -1297,8 +1270,8 @@ gmove(Node *f, Node *t)
 		}
 
 		// set round to zero mode during conversion
-		tempalloc(&t1, types[TUINT16]);
-		tempalloc(&t2, types[TUINT16]);
+		memname(&t1, types[TUINT16]);
+		memname(&t2, types[TUINT16]);
 		gins(AFSTCW, N, &t1);
 		gins(AMOVW, ncon(0xf7f), &t2);
 		gins(AFLDCW, &t2, N);
@@ -1309,8 +1282,6 @@ gmove(Node *f, Node *t)
 		else
 			gins(AFMOVVP, &r1, t);
 		gins(AFLDCW, &t1, N);
-		tempfree(&t2);
-		tempfree(&t1);
 		return;
 
 	case CASE(TFLOAT32, TINT8):
@@ -1320,7 +1291,7 @@ gmove(Node *f, Node *t)
 	case CASE(TFLOAT64, TUINT16):
 	case CASE(TFLOAT64, TUINT8):
 		// convert via int32.
-		tempalloc(&t1, types[TINT32]);
+		tempname(&t1, types[TINT32]);
 		gmove(f, &t1);
 		switch(tt) {
 		default:
@@ -1352,13 +1323,12 @@ gmove(Node *f, Node *t)
 			gmove(&t1, t);
 			break;
 		}
-		tempfree(&t1);
 		return;
 
 	case CASE(TFLOAT32, TUINT32):
 	case CASE(TFLOAT64, TUINT32):
 		// convert via int64.
-		tempalloc(&t1, types[TINT64]);
+		tempname(&t1, types[TINT64]);
 		gmove(f, &t1);
 		split64(&t1, &tlo, &thi);
 		gins(ACMPL, &thi, ncon(0));
@@ -1367,7 +1337,6 @@ gmove(Node *f, Node *t)
 		patch(p1, pc);
 		gmove(&tlo, t);
 		splitclean();
-		tempfree(&t1);
 		return;
 
 	case CASE(TFLOAT32, TUINT64):
@@ -1405,12 +1374,11 @@ gmove(Node *f, Node *t)
 		//	otherwise, subtract 2^63, convert, and add it back.
 
 		// set round to zero mode during conversion
-		tempalloc(&t1, types[TUINT16]);
-		tempalloc(&t2, types[TUINT16]);
+		memname(&t1, types[TUINT16]);
+		memname(&t2, types[TUINT16]);
 		gins(AFSTCW, N, &t1);
 		gins(AMOVW, ncon(0xf7f), &t2);
 		gins(AFLDCW, &t2, N);
-		tempfree(&t2);
 
 		// actual work
 		gmove(&two63f, &f0);
@@ -1432,7 +1400,6 @@ gmove(Node *f, Node *t)
 
 		// restore rounding mode
 		gins(AFLDCW, &t1, N);
-		tempfree(&t1);
 		return;
 
 	/*
@@ -1487,7 +1454,7 @@ gmove(Node *f, Node *t)
 		nodreg(&ax, types[TUINT32], D_AX);
 		nodreg(&dx, types[TUINT32], D_DX);
 		nodreg(&cx, types[TUINT32], D_CX);
-		tempalloc(&t1, f->type);
+		tempname(&t1, f->type);
 		split64(&t1, &tlo, &thi);
 		gmove(f, &t1);
 		gins(ACMPL, &thi, ncon(0));
@@ -1516,7 +1483,6 @@ gmove(Node *f, Node *t)
 		gmove(&r1, t);
 		patch(p2, pc);
 		splitclean();
-		tempfree(&t1);
 		return;
 
 	/*
@@ -1563,10 +1529,9 @@ gmove(Node *f, Node *t)
 
 	case CASE(TFLOAT64, TFLOAT32):
 		if(f->op == OREGISTER && t->op == OREGISTER) {
-			tempalloc(&r1, types[TFLOAT32]);
+			tempname(&r1, types[TFLOAT32]);
 			gins(AFMOVFP, f, &r1);
 			gins(AFMOVF, &r1, t);
-			tempfree(&r1);
 			return;
 		}
 		if(f->op == OREGISTER)
@@ -1597,10 +1562,9 @@ hard:
 
 hardmem:
 	// requires memory intermediate
-	tempalloc(&r1, cvt);
+	tempname(&r1, cvt);
 	gmove(f, &r1);
 	gmove(&r1, t);
-	tempfree(&r1);
 	return;
 
 fatal:

src/cmd/8g/opt.h

@@ -34,8 +34,6 @@
 #define	D_HI	D_NONE
 #define	D_LO	D_NONE
 
-#define	isregtype(t)	((t)>= D_AX && (t)<=D_R15)
-
 #define	BLOAD(r)	band(bnot(r->refbehind), r->refahead)
 #define	BSTORE(r)	band(bnot(r->calbehind), r->calahead)
 #define	LOAD(r)		(~r->refbehind.b[z] & r->refahead.b[z])

src/cmd/8g/reg.c

@@ -287,8 +287,12 @@ regopt(Prog *firstp)
 		case ASHRW:
 		case AIMULL:
 		case AIMULW:
+		case ANEGB:
 		case ANEGL:
+		case ANEGW:
+		case ANOTB:
 		case ANOTL:
+		case ANOTW:
 		case AADCL:
 		case ASBBL: