gc: Escape analysis.
For now it's switch-on-and-offable with -s, and the effects can be inspected
with -m. Defaults are the old codepaths.
R=rsc
CC=golang-dev
https://golang.org/cl/4634073
diff --git a/src/cmd/gc/select.c b/src/cmd/gc/select.c
index 909ad3a..973e9fe 100644
--- a/src/cmd/gc/select.c
+++ b/src/cmd/gc/select.c
@@ -59,7 +59,7 @@
break;
case OAS2RECV:
- // convert x, ok = <-c into OSELRECV(x, <-c) with ntest=ok
+ // convert x, ok = <-c into OSELRECV2(x, <-c) with ntest=ok
if(n->right->op != ORECV) {
yyerror("select assignment must have receive on right hand side");
break;
@@ -73,6 +73,7 @@
case ORECV:
// convert <-c into OSELRECV(N, <-c)
n = nod(OSELRECV, N, n);
+ n->typecheck = 1;
ncase->left = n;
break;
