code generation

R=r
OCL=21146
CL=21146

src/cmd/6g/cgen.c

@@ -9,7 +9,7 @@ cgen(Node *n, Node *res)
 {
 	Node *nl, *nr, *r;
 	Node n1, n2;
-	int a;
+	int a, f;
 	Prog *p1, *p2, *p3;
 	Addr addr;
 
@@ -48,6 +48,36 @@ cgen(Node *n, Node *res)
 			goto ret;
 		}
 
+		if(res->ullman >= UINF)
+			goto gen;
+
+		f = 1;	// gen thru register
+		switch(n->op) {
+		case OLITERAL:
+			if(isint[n->type->etype])
+			if(n->type->width <= 4)
+				f = 0;
+			break;
+		case OREGISTER:
+			f = 0;
+			break;
+		}
+
+		if(sudoaddable(res, n->type, &addr, &n1)) {
+			a = optoas(OAS, res->type);
+			if(f) {
+				regalloc(&n2, res->type, N);
+				cgen(n, &n2);
+				p1 = gins(a, &n2, N);
+				regfree(&n2);
+			} else
+				p1 = gins(a, n, N);
+			p1->to = addr;
+			regfree(&n1);
+			goto ret;
+		}
+
+	gen:
 		igen(res, &n1, N);
 		cgen(n, &n1);
 		regfree(&n1);
@@ -71,19 +101,20 @@ cgen(Node *n, Node *res)
 		goto ret;
 	}
 
-	if(sudoaddable(n, res->type, &addr)) {
+	if(sudoaddable(n, res->type, &addr, &n1)) {
 		a = optoas(OAS, n->type);
 		if(res->op == OREGISTER) {
 			p1 = gins(a, N, res);
 			p1->from = addr;
 		} else {
-			regalloc(&n1, n->type, N);
-			p1 = gins(a, N, &n1);
+			regalloc(&n2, n->type, &n1);
+			p1 = gins(a, N, &n2);
 			p1->from = addr;
-			gins(a, &n1, res);
-			regfree(&n1);
+			gins(a, &n2, res);
+			regfree(&n2);
 		}
-		return;
+		regfree(&n1);
+		goto ret;
 	}
 
 	switch(n->op) {
@@ -173,10 +204,10 @@ cgen(Node *n, Node *res)
 		regfree(&n1);
 		break;
 
-	case OINDEXPTR:
-	case OINDEX:
 	case ODOT:
 	case ODOTPTR:
+	case OINDEXPTR:
+	case OINDEX:
 	case OIND:
 		igen(n, &n1, res);
 		gmove(&n1, res);
@@ -286,13 +317,14 @@ abop:	// asymmetric binary
 		regalloc(&n1, nl->type, res);
 		cgen(nl, &n1);
 
-if(sudoaddable(nr, nl->type, &addr)) {
+		if(sudoaddable(nr, nl->type, &addr, &n2)) {
 			p1 = gins(a, N, &n1);
 			p1->from = addr;
 			gmove(&n1, res);
+			regfree(&n2);
 			regfree(&n1);
 			goto ret;
-}
+		}
 
 		regalloc(&n2, nr->type, N);
 		cgen(nr, &n2);

src/cmd/6g/gen.c

@@ -1165,15 +1165,10 @@ dodiv(int op, Node *nl, Node *nr, Node *res, Node *ax, Node *dx)
 		gmove(dx, res);
 }
 
-/*
- * this is hard because divide
- * is done in a fixed numerator
- * of combined DX:AX registers
- */
 void
 cgen_div(int op, Node *nl, Node *nr, Node *res)
 {
-	Node ax, dx, n3, tmpax, tmpdx;
+	Node ax, dx;
 	int rax, rdx;
 
 	rax = reg[D_AX];
@@ -1184,64 +1179,12 @@ cgen_div(int op, Node *nl, Node *nr, Node *res)
 	regalloc(&ax, nl->type, &ax);
 	regalloc(&dx, nl->type, &dx);
 
-	// clean out the AX register
-	if(rax && !samereg(res, &ax)) {
-		if(rdx && !samereg(res, &dx)) {
-			regalloc(&tmpdx, types[TINT64], N);
-			regalloc(&tmpax, types[TINT64], N);
-			regalloc(&n3, nl->type, N);		// dest for div
-
-			gins(AMOVQ, &dx, &tmpdx);
-			gins(AMOVQ, &ax, &tmpax);
-			dodiv(op, nl, nr, &n3, &ax, &dx);
-			gins(AMOVQ, &tmpax, &ax);
-			gins(AMOVQ, &tmpdx, &dx);
-			gmove(&n3, res);
-
-			regfree(&tmpdx);
-			regfree(&tmpax);
-			regfree(&n3);
-			goto ret;
-		}
-		regalloc(&tmpax, types[TINT64], N);
-		regalloc(&n3, nl->type, N);		// dest for div
-
-		gins(AMOVQ, &ax, &tmpax);
-		dodiv(op, nl, nr, &n3, &ax, &dx);
-		gins(AMOVQ, &tmpax, &ax);
-		gmove(&n3, res);
-
-		regfree(&tmpax);
-		regfree(&n3);
-		goto ret;
-	}
-
-	// clean out the DX register
-	if(rdx && !samereg(res, &dx)) {
-		regalloc(&tmpdx, types[TINT64], N);
-		regalloc(&n3, nl->type, N);		// dest for div
-
-		gins(AMOVQ, &dx, &tmpdx);
-		dodiv(op, nl, nr, &n3, &ax, &dx);
-		gins(AMOVQ, &tmpdx, &dx);
-		gmove(&n3, res);
-
-		regfree(&tmpdx);
-		regfree(&n3);
-		goto ret;
-	}
 	dodiv(op, nl, nr, res, &ax, &dx);
 
-ret:
 	regfree(&ax);
 	regfree(&dx);
 }
 
-/*
- * this is hard because shift
- * count is either constant
- * or the CL register
- */
 void
 cgen_shift(int op, Node *nl, Node *nr, Node *res)
 {
@@ -1271,25 +1214,7 @@ cgen_shift(int op, Node *nl, Node *nr, Node *res)
 	nodreg(&n1, types[TINT64], D_CX);
 	regalloc(&n1, nr->type, &n1);
 
-	// clean out the CL register
-	if(rcl) {
-		regalloc(&n2, types[TINT64], N);
-		gins(AMOVQ, &n1, &n2);
-		regfree(&n1);
-
-		reg[D_CX] = 0;
-		if(samereg(res, &n1))
-			cgen_shift(op, nl, nr, &n2);
-		else
-			cgen_shift(op, nl, nr, res);
-		reg[D_CX] = rcl;
-
-		gins(AMOVQ, &n2, &n1);
-		regfree(&n2);
-		goto ret;
-	}
-
-	regalloc(&n2, nl->type, res);	// can one shift the CL register
+	regalloc(&n2, nl->type, res);
 	if(nl->ullman >= nr->ullman) {
 		cgen(nl, &n2);
 		cgen(nr, &n1);

src/cmd/6g/gg.h

@@ -199,7 +199,7 @@ void	tempname(Node*, Type*);
 Plist*	newplist(void);
 int	isfat(Type*);
 void	setmaxarg(Type*);
-int	sudoaddable(Node*, Type*, Addr*);
+int	sudoaddable(Node*, Type*, Addr*, Node*);
 
 /*
  * list.c

src/cmd/6g/gsubr.c

@@ -113,7 +113,12 @@ ginit(void)
 		reg[i] = 0;
 	for(i=D_X0; i<=D_X7; i++)
 		reg[i] = 0;
-	reg[D_SP]++;
+	reg[D_AX]++;	// for divide
+	reg[D_CX]++;	// for shift
+	reg[D_DI]++;	// for movstring
+	reg[D_DX]++;	// for divide
+	reg[D_SI]++;	// for movstring
+	reg[D_SP]++;	// for stack
 }
 
 void
@@ -121,7 +126,12 @@ gclean(void)
 {
 	int i;
 
-	reg[D_SP]--;
+	reg[D_AX]--;	// for divide
+	reg[D_CX]--;	// for shift
+	reg[D_DI]--;	// for movstring
+	reg[D_DX]--;	// for divide
+	reg[D_SI]--;	// for movstring
+	reg[D_SP]--;	// for stack
 	for(i=D_AX; i<=D_R15; i++)
 		if(reg[i])
 			yyerror("reg %R left allocated\n", i);
@@ -1800,11 +1810,11 @@ dotoffset(Node *n, int *oary, Node **nn)
 }
 
 int
-sudoaddable(Node *n, Type *t, Addr *a)
+sudoaddable(Node *n, Type *t, Addr *a, Node *reg)
 {
 	int et, o, i;
 	int oary[10];
-	Node n1, n2, *nn;
+	Node n1, *nn;
 
 	if(n->type == T || t == T)
 		return 0;
@@ -1831,28 +1841,27 @@ sudoaddable(Node *n, Type *t, Addr *a)
 			return 0;
 		}
 
-		regalloc(&n1, types[tptr], N);
-		n2 = n1;
-		n2.op = OINDREG;
+		regalloc(reg, types[tptr], N);
+		n1 = *reg;
+		n1.op = OINDREG;
 		if(oary[0] >= 0) {
-			agen(nn, &n1);
-			n2.xoffset = oary[0];
+			agen(nn, reg);
+			n1.xoffset = oary[0];
 		} else {
-			cgen(nn, &n1);
-			n2.xoffset = -(oary[0]+1);
+			cgen(nn, reg);
+			n1.xoffset = -(oary[0]+1);
 		}
 
 		for(i=1; i<o; i++) {
 			if(oary[i] >= 0)
 				fatal("cant happen");
-			gins(AMOVQ, &n2, &n1);
-			n2.xoffset = -(oary[i]+1);
+			gins(AMOVQ, &n1, reg);
+			n1.xoffset = -(oary[i]+1);
 		}
 
 		a->type = D_NONE;
 		a->index = D_NONE;
-		naddr(&n2, a);
-		regfree(&n1);
+		naddr(&n1, a);
 		break;
 	}
 	return 1;