kc: import various changes from charles forsyth

diff --git a/sys/src/cmd/kc/cgen.c b/sys/src/cmd/kc/cgen.c
index a6b5771cbf4d04f1f429626b6931152c080ef9b3..aa3c2ebff3d2702c79417cfb61bc94a3d7e02e0c 100644 (file)
--- a/sys/src/cmd/kc/cgen.c
+++ b/sys/src/cmd/kc/cgen.c
@@ -1,5 +1,7 @@
 #include "gc.h"
 
+static void genasop(int, Node*, Node*, Node*);
+
 void
 cgen(Node *n, Node *nn)
 {
@@ -217,6 +219,8 @@ cgen(Node *n, Node *nn)
                                regfree(&nod2);
                        break;
                }
+               genasop(o, l, r, nn);
+               break;
 
        case OASLMUL:
        case OASLDIV:
@@ -226,29 +230,7 @@ cgen(Node *n, Node *nn)
        case OASMOD:
                if(l->op == OBIT)
                        goto asbitop;
-               if(l->complex >= r->complex) {
-                       if(l->addable < INDEXED)
-                               reglcgen(&nod2, l, Z);
-                       else
-                               nod2 = *l;
-                       regalloc(&nod, n, nn);
-                       cgen(r, &nod);
-               } else {
-                       regalloc(&nod, n, nn);
-                       cgen(r, &nod);
-                       if(l->addable < INDEXED)
-                               reglcgen(&nod2, l, Z);
-                       else
-                               nod2 = *l;
-               }
-               regalloc(&nod1, n, Z);
-               gopcode(OAS, &nod2, Z, &nod1);
-               gopcode(o, &nod, &nod1, &nod);
-               gopcode(OAS, &nod, Z, &nod2);
-               regfree(&nod);
-               regfree(&nod1);
-               if(l->addable < INDEXED)
-                       regfree(&nod2);
+               genasop(o, l, r, nn);
                break;
 
        asbitop:
@@ -517,6 +499,43 @@ cgen(Node *n, Node *nn)
        cursafe = curs;
 }
 
+static void
+genasop(int o, Node *l, Node *r, Node *nn)
+{
+       Node nod, nod1, nod2;
+       int hardleft;
+
+       hardleft = l->addable < INDEXED || l->complex >= FNX;
+       if(l->complex >= r->complex) {
+               if(hardleft)
+                       reglcgen(&nod2, l, Z);
+               else
+                       nod2 = *l;
+               regalloc(&nod1, r, Z);
+               cgen(r, &nod1);
+       } else {
+               regalloc(&nod1, r, Z);
+               cgen(r, &nod1);
+               if(hardleft)
+                       reglcgen(&nod2, l, Z);
+               else
+                       nod2 = *l;
+       }
+       if(nod1.type == nod2.type || !typefd[nod1.type->etype])
+               regalloc(&nod, &nod2, nn);
+       else
+               regalloc(&nod, &nod1, Z);
+       gmove(&nod2, &nod);
+       gopcode(o, &nod1, Z, &nod);
+       gmove(&nod, &nod2);
+       if(nn != Z)
+               gmove(&nod2, nn);
+       regfree(&nod);
+       regfree(&nod1);
+       if(hardleft)
+               regfree(&nod2);
+}
+
 void
 reglcgen(Node *t, Node *n, Node *nn)
 {
@@ -835,12 +854,12 @@ sugen(Node *n, Node *nn, long w)
 
        case OSTRUCT:
                /*
-                * rewrite so lhs has no fn call
+                * rewrite so lhs has no side effects
                 */
-               if(nn != Z && nn->complex >= FNX) {
+               if(nn != Z && side(nn)) {
                        nod1 = *n;
                        nod1.type = typ(TIND, n->type);
-                       regret(&nod2, &nod1);
+                       regalloc(&nod2, &nod1, Z);
                        lcgen(nn, &nod2);
                        regsalloc(&nod0, &nod1);
                        gopcode(OAS, &nod2, Z, &nod0);