From 1ee83f851dd7b70564c54f60575957ed84a368b7 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Mon, 16 Nov 2009 17:40:47 -0800
Subject: [PATCH] gc: change "can we const evaluate this" from blacklist to
 whitelist

R=ken2
https://golang.org/cl/155074
---
 src/cmd/gc/const.c | 36 ++++++++++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 6 deletions(-)

diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index b11ab1c7f8..cca13b9528 100644
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -329,14 +329,38 @@ evconst(Node *n)
 	Val v;
 	Mpint b;
 
+	// pick off just the opcodes that can be
+	// constant evaluated.
 	switch(n->op) {
-	case OMAKE:
-	case OMAKEMAP:
-	case OMAKESLICE:
-	case OMAKECHAN:
-	case ODCLCONST:
-	case OCONVIFACE:
+	default:
 		return;
+	case OADD:
+	case OADDSTR:
+	case OAND:
+	case OANDAND:
+	case OANDNOT:
+	case OARRAYBYTESTR:
+	case OCOM:
+	case OCONV:
+	case ODIV:
+	case OEQ:
+	case OGE:
+	case OGT:
+	case OLE:
+	case OLSH:
+	case OLT:
+	case OMINUS:
+	case OMOD:
+	case OMUL:
+	case ONE:
+	case ONOT:
+	case OOR:
+	case OOROR:
+	case OPLUS:
+	case ORSH:
+	case OSUB:
+	case OXOR:
+		break;
 	}
 
 	nl = n->left;
-- 
2.48.1