arm optimizer bug fixes

R=rsc
CC=golang-dev
https://golang.org/cl/3913043

2 files changed, 110 insertions, 80 deletions

diff --git a/src/cmd/5g/peep.c b/src/cmd/5g/peep.c
index 3e6bf3eb98..32333e8a9f 100644
--- a/src/cmd/5g/peep.c
+++ b/src/cmd/5g/peep.c
@@ -37,6 +37,7 @@ int	shiftprop(Reg *r);
 void	constprop(Adr *c1, Adr *v1, Reg *r);
 void	predicate(void);
 int	copyau1(Prog *p, Adr *v);
+int	isdconst(Addr *a);
 
 void
 peep(void)
@@ -81,30 +82,42 @@ loop1:
 	t = 0;
 	for(r=firstr; r!=R; r=r->link) {
 		p = r->prog;
-		if(p->as == ASLL || p->as == ASRL || p->as == ASRA) {
+		switch(p->as) {
+		case ASLL:
+		case ASRL:
+		case ASRA:
 			/*
 			 * elide shift into D_SHIFT operand of subsequent instruction
 			 */
 			if(shiftprop(r)) {
 				excise(r);
 				t++;
+				break;
 			}
-		}
-		if(p->as == AMOVW || p->as == AMOVF || p->as == AMOVD)
-		if(regtyp(&p->to)) {
-			if(p->from.type == D_CONST)
+			break;
+
+		case AMOVW:
+		case AMOVF:
+		case AMOVD:
+			if(!regtyp(&p->to))
+				break;
+			if(isdconst(&p->from)) {
 				constprop(&p->from, &p->to, r->s1);
-			else
-			if(regtyp(&p->from))
-			if(p->from.type == p->to.type) {
-				if(copyprop(r)) {
-					excise(r);
-					t++;
-				} else
-				if(subprop(r) && copyprop(r)) {
-					excise(r);
-					t++;
-				}
+				break;
+			}
+			if(!regtyp(&p->from))
+				break;
+			if(p->from.type != p->to.type)
+				break;
+			if(copyprop(r)) {
+				excise(r);
+				t++;
+				break;
+			}
+			if(subprop(r) && copyprop(r)) {
+				excise(r);
+				t++;
+				break;
 			}
 		}
 	}
@@ -122,7 +135,7 @@ loop1:
 			/*
 			 * EOR -1,x,y => MVN x,y
 			 */
-			if(p->from.type == D_CONST && p->from.offset == -1) {
+			if(isdconst(&p->from) && p->from.offset == -1) {
 				p->as = AMVN;
 				p->from.type = D_REG;
 				if(p->reg != NREG)
@@ -170,7 +183,7 @@ loop1:
 			/*
 			 * elide CMP $0,x if calculation of x can set condition codes
 			 */
-			if(p->from.type != D_CONST || p->from.offset != 0)
+			if(isdconst(&p->from) || p->from.offset != 0)
 				continue;
 			r2 = r->s1;
 			if(r2 == R)
@@ -668,12 +681,14 @@ shiftprop(Reg *r)
 		}
 		break;
 	}
+
 	/* make the substitution */
 	p2->from.type = D_SHIFT;
 	p2->from.reg = NREG;
 	o = p->reg;
 	if(o == NREG)
 		o = p->to.reg;
+
 	switch(p->from.type){
 	case D_CONST:
 		o |= (p->from.offset&0x1f)<<7;
@@ -735,7 +750,7 @@ findinc(Reg *r, Reg *r2, Adr *v)
 		case 4: /* set and used */
 			p = r1->prog;
 			if(p->as == AADD)
-			if(p->from.type == D_CONST)
+			if(isdconst(&p->from))
 			if(p->from.offset > -4096 && p->from.offset < 4096)
 				return r1;
 		default:
@@ -990,7 +1005,6 @@ copyu(Prog *p, Adr *v, Adr *s)
 			return 1;
 		return 0;
 
-
 	case AADD:	/* read, read, write */
 	case ASUB:
 	case ARSB:
@@ -1192,6 +1206,10 @@ copyau(Adr *a, Adr *v)
 	if(copyas(a, v))
 		return 1;
 	if(v->type == D_REG) {
+		if(a->type == D_CONST && a->reg != NREG) {
+			if(v->reg == a->reg)
+				return 1;
+		} else
 		if(a->type == D_OREG) {
 			if(v->reg == a->reg)
 				return 1;
@@ -1320,19 +1338,22 @@ isbranch(Prog *p)
 int
 predicable(Prog *p)
 {
-	if (isbranch(p)
-		|| p->as == ANOP
-		|| p->as == AXXX
-		|| p->as == ADATA
-		|| p->as == AGLOBL
-		|| p->as == AGOK
-		|| p->as == AHISTORY
-		|| p->as == ANAME
-		|| p->as == ASIGNAME
-		|| p->as == ATEXT
-		|| p->as == AWORD
-		|| p->as == ABCASE
-		|| p->as == ACASE)
+	switch(p->as) {
+	case ANOP:
+	case AXXX:
+	case ADATA:
+	case AGLOBL:
+	case AGOK:
+	case AHISTORY:
+	case ANAME:
+	case ASIGNAME:
+	case ATEXT:
+	case AWORD:
+	case ABCASE:
+	case ACASE:
+		return 0;
+	}
+	if(isbranch(p))
 		return 0;
 	return 1;
 }
@@ -1347,18 +1368,23 @@ predicable(Prog *p)
 int
 modifiescpsr(Prog *p)
 {
-	return (p->scond&C_SBIT)
-		|| p->as == ATST
-		|| p->as == ATEQ
-		|| p->as == ACMN
-		|| p->as == ACMP
-		|| p->as == AMULU
-		|| p->as == ADIVU
-		|| p->as == AMUL
-		|| p->as == ADIV
-		|| p->as == AMOD
-		|| p->as == AMODU
-		|| p->as == ABL;
+	switch(p->as) {
+	case ATST:
+	case ATEQ:
+	case ACMN:
+	case ACMP:
+	case AMULU:
+	case ADIVU:
+	case AMUL:
+	case ADIV:
+	case AMOD:
+	case AMODU:
+	case ABL:
+		return 1;
+	}
+	if(p->scond & C_SBIT)
+		return 1;
+	return 0;
 }
 
 /*
@@ -1401,10 +1427,10 @@ joinsplit(Reg *r, Joininfo *j)
 	return Toolong;
 }
 
-Reg *
+Reg*
 successor(Reg *r)
 {
-	if (r->s1)
+	if(r->s1)
 		return r->s1;
 	else
 		return r->s2;
@@ -1418,23 +1444,24 @@ applypred(Reg *rstart, Joininfo *j, int cond, int branch)
 
 	if(j->len == 0)
 		return;
-	if (cond == Truecond)
+	if(cond == Truecond)
 		pred = predinfo[rstart->prog->as - ABEQ].scond;
 	else
 		pred = predinfo[rstart->prog->as - ABEQ].notscond;
 
-	for (r = j->start; ; r = successor(r)) {
+	for(r = j->start;; r = successor(r)) {
 		if (r->prog->as == AB) {
 			if (r != j->last || branch == Delbranch)
 				excise(r);
 			else {
-			  if (cond == Truecond)
-				r->prog->as = predinfo[rstart->prog->as - ABEQ].opcode;
-			  else
-				r->prog->as = predinfo[rstart->prog->as - ABEQ].notopcode;
+				if (cond == Truecond)
+					r->prog->as = predinfo[rstart->prog->as - ABEQ].opcode;
+				else
+					r->prog->as = predinfo[rstart->prog->as - ABEQ].notopcode;
 			}
 		}
-		else if (predicable(r->prog))
+		else
+		if (predicable(r->prog))
 			r->prog->scond = (r->prog->scond&~C_SCOND)|pred;
 		if (r->s1 != r->link) {
 			r->s1 = r->link;
@@ -1474,3 +1501,11 @@ predicate(void)
 		}
 	}
 }
+
+int
+isdconst(Addr *a)
+{
+	if(a->type == D_CONST && a->reg == NREG)
+		return 1;
+	return 0;
+}
diff --git a/src/cmd/5g/reg.c b/src/cmd/5g/reg.c
index 46471a016c..8f998b8764 100644
--- a/src/cmd/5g/reg.c
+++ b/src/cmd/5g/reg.c
@@ -102,7 +102,7 @@ excise(Reg *r)
 	p->scond = zprog.scond;
 	p->from = zprog.from;
 	p->to = zprog.to;
-	p->reg = zprog.reg; /**/
+	p->reg = zprog.reg;
 }
 
 static void
@@ -139,22 +139,16 @@ regopt(Prog *firstp)
 
 	if(first == 0) {
 		fmtinstall('Q', Qconv);
-//		exregoffset = D_R13;	// R14,R15 are external
 	}
 	first++;
 
-//if(!debug['K'])
-//	return;
-
-//if(first != 19) {
-//	return;
-//}
-
-//print("optimizing %S\n", curfn->nname->sym);
-
-//debug['R'] = 2;
-//debug['P'] = 2;
-
+	if(debug['K']) {
+		if(first != 20)
+			return;
+//		debug['R'] = 2;
+//		debug['P'] = 2;
+		print("optimizing %S\n", curfn->nname->sym);
+	}
 
 	// count instructions
 	nr = 0;
@@ -189,7 +183,6 @@ regopt(Prog *firstp)
 	 * allocate pcs
 	 * find use and set of variables
 	 */
-if(0) print("pass 1\n");
 	nr = 0;
 	for(p=firstp; p != P; p = p->link) {
 		switch(p->as) {
@@ -284,7 +277,6 @@ if(0) print("pass 1\n");
 	 * turn branch references to pointers
 	 * build back pointers
 	 */
-if(0) print("pass 2\n");
 	for(r=firstr; r!=R; r=r->link) {
 		p = r->prog;
 		if(p->to.type == D_BRANCH) {
@@ -311,7 +303,6 @@ if(0) print("pass 2\n");
 	 * pass 2.5
 	 * find looping structure
 	 */
-if(0) print("pass 2.5\n");
 	for(r = firstr; r != R; r = r->link)
 		r->active = 0;
 	change = 0;
@@ -323,7 +314,6 @@ if(0) print("pass 2.5\n");
 	 * 	back until flow graph is complete
 	 */
 loop1:
-if(0) print("loop 1\n");
 	change = 0;
 	for(r = firstr; r != R; r = r->link)
 		r->active = 0;
@@ -331,7 +321,6 @@ if(0) print("loop 1\n");
 		if(r->prog->as == ARET)
 			prop(r, zbits, zbits);
 loop11:
-if(0) print("loop 11\n");
 	/* pick up unreachable code */
 	i = 0;
 	for(r = firstr; r != R; r = r1) {
@@ -353,7 +342,6 @@ if(0) print("loop 11\n");
 	 * 	forward until graph is complete
 	 */
 loop2:
-if(0) print("loop 2\n");
 	change = 0;
 	for(r = firstr; r != R; r = r->link)
 		r->active = 0;
@@ -400,7 +388,6 @@ if(0) print("loop 2\n");
 	 * isolate regions
 	 * calculate costs (paint1)
 	 */
-if(0) print("pass 5\n");
 	r = firstr;
 	if(r) {
 		for(z=0; z<BITS; z++)
@@ -490,7 +477,6 @@ brk:
 	 * pass 7
 	 * peep-hole on basic block
 	 */
-if(0) print("pass 7\n");
 	if(!debug['R'] || debug['P']) {
 		peep();
 	}
@@ -652,8 +638,12 @@ mkvar(Reg *r, Adr *a, int docon)
 		print("type %d %d %D\n", t, a->name, a);
 		goto none;
 
-	case D_NONE:
 	case D_CONST:
+		if(a->reg != NREG)
+			r->regu |= RtoB(a->reg);
+		// fallthrough
+
+	case D_NONE:
 	case D_FCONST:
 	case D_BRANCH:
 		goto none;
@@ -1028,9 +1018,6 @@ allreg(uint32 b, Rgn *r)
 		}
 		break;
 
-	case TINT64:
-	case TUINT64:
-	case TPTR64:
 	case TFLOAT32:
 	case TFLOAT64:
 	case TFLOAT:
@@ -1040,6 +1027,14 @@ allreg(uint32 b, Rgn *r)
 			return FtoB(i);
 		}
 		break;
+
+	case TINT64:
+	case TUINT64:
+	case TPTR64:
+	case TINTER:
+	case TSTRUCT:
+	case TARRAY:
+		break;
 	}
 	return 0;
 }