code review 92760044: runtime: use duff zero and copy to initialize memory

src/cmd/5g/prog.c

 // Copyright 2013 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 #include <u.h>
 #include <libc.h>
 #include "gg.h"
 #include "opt.h"
 
 enum
@@ skipping 75 matching lines @@
         [AMOVDW]=               {SizeL | LeftRead | RightWrite | Conv},
         [AMOVFD]=               {SizeD | LeftRead | RightWrite | Conv},
         [AMOVFW]=               {SizeL | LeftRead | RightWrite | Conv},
 
         // Moves.
         [AMOVB]=                {SizeB | LeftRead | RightWrite | Move},
         [AMOVD]=                {SizeD | LeftRead | RightWrite | Move},
         [AMOVF]=                {SizeF | LeftRead | RightWrite | Move},
         [AMOVH]=                {SizeW | LeftRead | RightWrite | Move},
         [AMOVW]=                {SizeL | LeftRead | RightWrite | Move},
+        // In addtion, duffzero reads R0,R1 and writes R1.  This fact is
+        // encoded in peep.c
+        [ADUFFZERO]=            {Call},
+        // In addtion, duffcopy reads R1,R2 and writes R0,R1,R2.  This fact is
+        // encoded in peep.c
+        [ADUFFCOPY]=            {Call},
 
         // These should be split into the two different conversions instead
         // of overloading the one.
         [AMOVBS]=               {SizeB | LeftRead | RightWrite | Conv},
         [AMOVBU]=               {SizeB | LeftRead | RightWrite | Conv},
         [AMOVHS]=               {SizeW | LeftRead | RightWrite | Conv},
         [AMOVHU]=               {SizeW | LeftRead | RightWrite | Conv},
 ········
         // Jumps.
         [AB]=           {Jump | Break},
@@ skipping 30 matching lines @@
         }
 
         if((info->flags & RegRead) && p->reg == NREG) {
                 info->flags &= ~RegRead;
                 info->flags |= CanRegRead | RightRead;
         }
 ········
         if(((p->scond & C_SCOND) != C_SCOND_NONE) && (info->flags & RightWrite))
                 info->flags |= RightRead;
 }