code review 7395050: cmd/6g, cmd/8g: switch to DX for indirect call block

src/cmd/6g/ggen.c

 // Copyright 2009 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.
 
 #undef  EXTERN
 #define EXTERN
 #include <u.h>
 #include <libc.h>
 #include "gg.h"
 #include "opt.h"
@@ skipping 59 matching lines @@
 
         case 0: // normal call
         case -1:        // normal call but no return
                 if(f->op == ONAME && f->class == PFUNC) {
                         p = gins(ACALL, N, f);
                         afunclit(&p->to, f);
                         if(proc == -1 || noreturn(p))
                                 gins(AUNDEF, N, N);
                         break;
                 }
-                nodreg(&reg, types[tptr], D_AX);
+                nodreg(&reg, types[tptr], D_DX);
                 nodreg(&r1, types[tptr], D_BX);
                 gmove(f, &reg);
                 reg.op = OINDREG;
                 gmove(&reg, &r1);
                 gins(ACALL, N, &r1);
                 break;
 ········
         case 3: // normal call of c function pointer
                 gins(ACALL, N, f);
                 break;
@@ skipping 877 matching lines @@
                 gins(ASTOSB, N, N);     // STOB AL,*(DI)+
         } else
         while(c > 0) {
                 gins(ASTOSB, N, N);     // STOB AL,*(DI)+
                 c--;
         }
 
         restx(&n1, &oldn1);
         restx(&ax, &oldax);
 }