code review 9101048: cmd/gc: inline copy in frontend to call memmove directly.

src/cmd/8g/cgen.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.
 
 // TODO(rsc):
 //      assume CLD?
 
 #include <u.h>
 #include <libc.h>
 #include "gg.h"
@@ skipping 91 matching lines @@
                 if(n->type->width < 0)
                         fatal("forgot to compute width for %T", n->type);
                 sgen(n, res, n->type->width);
                 return;
         }
 
         // update addressability for string, slice
         // can't do in walk because n->left->addable
         // changes if n->left is an escaping local variable.
         switch(n->op) {
+        case OSPTR:
         case OLEN:
                 if(isslice(n->left->type) || istype(n->left->type, TSTRING))
                         n->addable = n->left->addable;
                 break;
         case OCAP:
                 if(isslice(n->left->type))
                         n->addable = n->left->addable;
                 break;
         case OITAB:
                 n->addable = n->left->addable;
@@ skipping 155 matching lines @@
         case OIND:
         case ONAME:     // PHEAP or PPARAMREF var
                 igen(n, &n1, res);
                 gmove(&n1, res);
                 regfree(&n1);
                 break;
 
         case OITAB:
                 igen(nl, &n1, res);
                 n1.type = ptrto(types[TUINTPTR]);
+                gmove(&n1, res);
+                regfree(&n1);
+                break;
+
+        case OSPTR:
+                // pointer is the first word of string or slice.
+                if(isconst(nl, CTSTR)) {
+                        regalloc(&n1, types[tptr], res);
+                        p1 = gins(ALEAL, N, &n1);
+                        datastring(nl->val.u.sval->s, nl->val.u.sval->len, &p1->from);
+                        gmove(&n1, res);
+                        regfree(&n1);
+                        break;
+                }
+                igen(nl, &n1, res);
+                n1.type = n->type;
                 gmove(&n1, res);
                 regfree(&n1);
                 break;
 
         case OLEN:
                 if(istype(nl->type, TMAP) || istype(nl->type, TCHAN)) {
                         // map has len in the first 32-bit word.
                         // a zero pointer means zero length
                         tempname(&n1, types[tptr]);
                         cgen(nl, &n1);
@@ skipping 1115 matching lines @@
                 regfree(&nodl);
         return 0;
 
 yes:
         if(freer)
                 regfree(&nodr);
         if(freel)
                 regfree(&nodl);
         return 1;
 }