indexing optimizations and bug fix

R=r
OCL=19886
CL=19886

diff --git a/src/cmd/6g/cgen.c b/src/cmd/6g/cgen.c
index d6f27a929609daadc75e1b9f71b746631b13f935..74e945e65488d4efb054d666b5cc25a4223bbfb5 100644 (file)
--- a/src/cmd/6g/cgen.c
+++ b/src/cmd/6g/cgen.c
@@ -351,9 +351,12 @@ agen(Node *n, Node *res)
                if(nr->addable)
                        goto iprad;
                if(nl->addable) {
-                       regalloc(&n1, nr->type, N);
-                       cgen(nr, &n1);
-                       cgen(nl, res);
+                       if(whatis(nr) != Wlitint) {
+                               regalloc(&n1, nr->type, N);
+                               cgen(nr, &n1);
+                       }
+                       regalloc(&n3, types[tptr], res);
+                       cgen(nl, &n3);
                        goto index;
                }
                cgen(nr, res);
@@ -361,9 +364,12 @@ agen(Node *n, Node *res)
                gmove(res, &tmp);
 
        iprad:
-               cgen(nl, res);
-               regalloc(&n1, nr->type, N);
-               cgen(nr, &n1);
+               regalloc(&n3, types[tptr], res);
+               cgen(nl, &n3);
+               if(whatis(nr) != Wlitint) {
+                       regalloc(&n1, nr->type, N);
+                       cgen(nr, &n1);
+               }
                goto index;
 
        case OINDEX:
@@ -371,9 +377,12 @@ agen(Node *n, Node *res)
                if(nr->addable)
                        goto irad;
                if(nl->addable) {
-                       regalloc(&n1, nr->type, N);
-                       cgen(nr, &n1);
-                       agen(nl, res);
+                       if(whatis(nr) != Wlitint) {
+                               regalloc(&n1, nr->type, N);
+                               cgen(nr, &n1);
+                       }
+                       regalloc(&n3, types[tptr], res);
+                       agen(nl, &n3);
                        goto index;
                }
                cgen(nr, res);
@@ -381,66 +390,39 @@ agen(Node *n, Node *res)
                gmove(res, &tmp);
 
        irad:
-               agen(nl, res);
-               regalloc(&n1, nr->type, N);
-               cgen(nr, &n1);
+               regalloc(&n3, types[tptr], res);
+               agen(nl, &n3);
+               if(whatis(nr) != Wlitint) {
+                       regalloc(&n1, nr->type, N);
+                       cgen(nr, &n1);
+               }
                goto index;
 
        index:
-               // &a is in res
-               // i is in &n1
+               // &a is in &n3 (allocated in res)
+               // i is in &n1 (if not constant)
                // w is width
 
                if(w == 0)
                        fatal("index is zero width");
 
-               if(isptrdarray(nl->type)) {
-                       regalloc(&n2, types[tptr], res);
-                       gmove(res, &n2);
-
-                       if(!debug['B']) {
-                               // check bounds
-                               n3 = n2;
-                               n3.op = OINDREG;
-                               n3.type = types[tptr];
-                               n3.xoffset = offsetof(Array, nel);
-                               gins(optoas(OCMP, types[TUINT32]), &n1, &n3);
-
-                               p1 = gbranch(optoas(OLT, types[TUINT32]), T);
-
-                               gins(ACALL, N, throwindex);
-                               patch(p1, pc);
-                       }
-
-                       // fetch array base from dope
-                       n3 = n2;
-                       n3.op = OINDREG;
-                       n3.type = types[tptr];
-                       n3.xoffset = offsetof(Array, array);
-                       gins(AMOVQ, &n3, &n2);
-                       gmove(&n2, res);
-                       regfree(&n2);
-               } else
-                       if(!debug['B']) {
-                               // check bounds
-                               nodconst(&n3, types[TUINT32], nl->type->bound);
-                               if(isptrarray(nl->type))
-                                       nodconst(&n3, types[TUINT32], nl->type->type->bound);
-                               gins(optoas(OCMP, types[TUINT32]), &n1, &n3);
-
-                               p1 = gbranch(optoas(OLT, types[TUINT32]), T);
-                               gins(ACALL, N, throwindex);
-                               patch(p1, pc);
-                       }
-
                if(whatis(nr) == Wlitint) {
-                       regfree(&n1);
+                       if(isptrdarray(nl->type)) {
+                               n1 = n3;
+                               n1.op = OINDREG;
+                               n1.type = types[tptr];
+                               n1.xoffset = offsetof(Array, array);
+                               gmove(&n1, &n3);
+                       }
                        v = mpgetfix(nr->val.u.xval);
                        nodconst(&n2, types[tptr], v*w);
-                       gins(optoas(OADD, types[tptr]), &n2, res);
+                       gins(optoas(OADD, types[tptr]), &n2, &n3);
+                       gmove(&n3, res);
+                       regfree(&n3);
                        break;
                }
 
+               // type of the index
                t = types[TUINT64];
                if(issigned[n1.type->etype])
                        t = types[TINT64];
@@ -449,10 +431,41 @@ agen(Node *n, Node *res)
                gmove(&n1, &n2);
                regfree(&n1);
 
-               nodconst(&n3, t, w);                    // w
-               gins(optoas(OMUL, t), &n3, &n2);
-               gins(optoas(OADD, types[tptr]), &n2, res);
+               if(!debug['B']) {
+                       // check bounds
+                       if(isptrdarray(nl->type)) {
+                               n1 = n3;
+                               n1.op = OINDREG;
+                               n1.type = types[tptr];
+                               n1.xoffset = offsetof(Array, nel);
+                       } else {
+                               nodconst(&n1, types[TUINT64], nl->type->bound);
+                               if(isptrarray(nl->type))
+                                       nodconst(&n1, types[TUINT64], nl->type->type->bound);
+                       }
+                       gins(optoas(OCMP, types[TUINT64]), &n2, &n1);
+                       p1 = gbranch(optoas(OLT, types[TUINT64]), T);
+                       gins(ACALL, N, throwindex);
+                       patch(p1, pc);
+               }
+
+               if(w != 1) {
+                       nodconst(&n1, t, w);                    // w
+                       gins(optoas(OMUL, t), &n1, &n2);
+               }
+
+               if(isptrdarray(nl->type)) {
+                       n1 = n3;
+                       n1.op = OINDREG;
+                       n1.type = types[tptr];
+                       n1.xoffset = offsetof(Array, array);
+                       gmove(&n1, &n3);
+               }
+               gins(optoas(OADD, types[tptr]), &n2, &n3);
+               gmove(&n3, res);
+
                regfree(&n2);
+               regfree(&n3);
                break;
 
        case OIND: