shift for non-64 bit integers.
R=rsc
http://go/go-review/1015017
diff --git a/src/cmd/5g/cgen.c b/src/cmd/5g/cgen.c
index e213ddf..bcbc979 100644
--- a/src/cmd/5g/cgen.c
+++ b/src/cmd/5g/cgen.c
@@ -244,11 +244,14 @@
// asymmetric binary
case OSUB:
- case OLSH:
- case ORSH:
a = optoas(n->op, nl->type);
goto abop;
+ case OLSH:
+ case ORSH:
+ cgen_shift(n->op, nl, nr, res);
+ break;
+
case OCONV:
if(eqtype(n->type, nl->type) || noconv(n->type, nl->type)) {
cgen(nl, res);
diff --git a/src/cmd/5g/gg.h b/src/cmd/5g/gg.h
index 04b16d2..98e5278 100644
--- a/src/cmd/5g/gg.h
+++ b/src/cmd/5g/gg.h
@@ -102,6 +102,7 @@
Prog * gregshift(int as, Node *lhs, int32 stype, Node *reg, Node *rhs);
void naddr(Node*, Addr*, int);
void cgen_aret(Node*, Node*);
+void cgen_shift(int, Node*, Node*, Node*);
/*
* cgen64.c
diff --git a/src/cmd/5g/ggen.c b/src/cmd/5g/ggen.c
index ddd6936..a224320 100644
--- a/src/cmd/5g/ggen.c
+++ b/src/cmd/5g/ggen.c
@@ -536,6 +536,95 @@
return 1;
}
+/*
+ * generate shift according to op, one of:
+ * res = nl << nr
+ * res = nl >> nr
+ */
+void
+cgen_shift(int op, Node *nl, Node *nr, Node *res)
+{
+ Node n1, n2, n3, t;
+ int w;
+ Prog *p1, *p2, *p3;
+ uvlong sc;
+
+ if(nl->type->width > 4)
+ fatal("cgen_shift %T", nl->type);
+
+ w = nl->type->width * 8;
+
+ if(nr->op == OLITERAL) {
+ regalloc(&n1, nl->type, res);
+ cgen(nl, &n1);
+ sc = mpgetfix(nr->val.u.xval);
+ if(sc == 0) {
+ return;
+ } else if(sc >= nl->type->width*8) {
+ if(op == ORSH && issigned[nl->type->etype])
+ gshift(AMOVW, &n1, SHIFT_AR, w, &n1);
+ else
+ gins(AEOR, &n1, &n1);
+ } else {
+ if(op == ORSH && issigned[nl->type->etype])
+ gshift(AMOVW, &n1, SHIFT_AR, sc, &n1);
+ else if(op == ORSH)
+ gshift(AMOVW, &n1, SHIFT_LR, sc, &n1);
+ else // OLSH
+ gshift(AMOVW, &n1, SHIFT_LL, sc, &n1);
+ }
+ gmove(&n1, res);
+ regfree(&n1);
+ return;
+ }
+
+ if(nl->ullman >= nr->ullman) {
+ regalloc(&n2, nl->type, res);
+ cgen(nl, &n2);
+ regalloc(&n1, nr->type, N);
+ cgen(nr, &n1);
+ } else {
+ regalloc(&n1, nr->type, N);
+ cgen(nr, &n1);
+ regalloc(&n2, nl->type, res);
+ cgen(nl, &n2);
+ }
+
+ // test for shift being 0
+ p1 = gins(AMOVW, &n1, &n1);
+ p1->scond |= C_SBIT;
+ p3 = gbranch(ABEQ, T);
+
+ // test and fix up large shifts
+ regalloc(&n3, nr->type, N);
+ nodconst(&t, types[TUINT32], w);
+ gmove(&t, &n3);
+ gcmp(ACMP, &n1, &n3);
+ if(op == ORSH) {
+ if(issigned[nl->type->etype]) {
+ p1 = gshift(AMOVW, &n2, SHIFT_AR, w-1, &n2);
+ p2 = gregshift(AMOVW, &n2, SHIFT_AR, &n1, &n2);
+ } else {
+ p1 = gins(AEOR, &n2, &n2);
+ p2 = gregshift(AMOVW, &n2, SHIFT_LR, &n1, &n2);
+ }
+ p1->scond = C_SCOND_HS;
+ p2->scond = C_SCOND_LO;
+ } else {
+ p1 = gins(AEOR, &n2, &n2);
+ p2 = gregshift(AMOVW, &n2, SHIFT_LL, &n1, &n2);
+ p1->scond = C_SCOND_HS;
+ p2->scond = C_SCOND_LO;
+ }
+ regfree(&n3);
+
+ patch(p3, pc);
+ gmove(&n2, res);
+
+ regfree(&n1);
+ regfree(&n2);
+}
+
void
clearfat(Node *nl)
{
diff --git a/src/cmd/5g/gsubr.c b/src/cmd/5g/gsubr.c
index bd5f0de..b14c7d2 100644
--- a/src/cmd/5g/gsubr.c
+++ b/src/cmd/5g/gsubr.c
@@ -923,6 +923,7 @@
}
/* generate a comparison
+TODO(kaib): one of the args can actually be a small constant. relax the constraint and fix call sites.
*/
Prog*
gcmp(int as, Node *lhs, Node *rhs)
diff --git a/src/cmd/8g/ggen.c b/src/cmd/8g/ggen.c
index 3f535cf..99c8b78 100644
--- a/src/cmd/8g/ggen.c
+++ b/src/cmd/8g/ggen.c
@@ -627,7 +627,7 @@
uvlong sc;
if(nl->type->width > 4)
- fatal("cgen_shift %T", nl->type->width);
+ fatal("cgen_shift %T", nl->type);
w = nl->type->width * 8;
