[dev.power64] 9g: proginfo fixes

For D_OREG addresses, store the used registers in regindex
instead of reguse because they're really part of addressing.

Add implicit register use/set for DUFFZERO/DUFFCOPY.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/174050044

src/cmd/9g/prog.c

@@ -96,11 +96,8 @@ static ProgInfo progtable[ALAST] = {
 	[ABGT]=		{Cjmp},
 	[ABLE]=		{Cjmp},
 	[ARETURN]=	{Break},
-	// In addtion, duffzero reads R0,R2 and writes R2.  This fact must be
-	// encoded in peep.c (TODO)
+
 	[ADUFFZERO]=	{Call},
-	// In addtion, duffcopy reads R0,R2,R3 and writes R2,R3.  This fact must be
-	// encoded in peep.c (TODO)
 	[ADUFFCOPY]=	{Call},
 };
 
@@ -118,14 +115,14 @@ proginfo(ProgInfo *info, Prog *p)
 		info->flags |= /*CanRegRead |*/ RightRead;
 	}
 
-	if(p->from.type == D_OREG && p->from.reg != NREG) {
-		info->reguse |= RtoB(p->from.reg);
+	if((p->from.type == D_OREG || p->from.type == D_CONST) && p->from.reg != NREG) {
+		info->regindex |= RtoB(p->from.reg);
 		if(info->flags & PostInc) {
 			info->regset |= RtoB(p->from.reg);
 		}
 	}
-	if(p->to.type == D_OREG && p->to.reg != NREG) {
-		info->reguse |= RtoB(p->to.reg);
+	if((p->to.type == D_OREG || p->to.type == D_CONST) && p->to.reg != NREG) {
+		info->regindex |= RtoB(p->to.reg);
 		if(info->flags & PostInc) {
 			info->regset |= RtoB(p->to.reg);
 		}
@@ -135,4 +132,13 @@ proginfo(ProgInfo *info, Prog *p)
 		info->flags &= ~LeftRead;
 		info->flags |= LeftAddr;
 	}
+
+	if(p->as == ADUFFZERO) {
+		info->reguse |= RtoB(0) | RtoB(2);
+		info->regset |= RtoB(2);
+	}
+	if(p->as == ADUFFCOPY) {
+		info->reguse |= RtoB(0) | RtoB(2) | RtoB(3);
+		info->regset |= RtoB(2) | RtoB(3);
+	}
 }