cmd/8c: disable use of prefetch with GO386=387

Fixes #4798.

R=ken2
CC=golang-dev
https://golang.org/cl/7323061

diff --git a/src/cmd/8c/txt.c b/src/cmd/8c/txt.c
index d7873e385536b38c64dca0d35db57a2bf8f91c73..1b7617bc52734e7e41e86cf0fd6392542055dbb1 100644 (file)
--- a/src/cmd/8c/txt.c
+++ b/src/cmd/8c/txt.c
@@ -1396,6 +1396,9 @@ gprefetch(Node *n)
 {
        Node n1;
        
+       if(strcmp(getgo386(), "sse2") != 0) // assume no prefetch on old machines
+               return;
+
        regalloc(&n1, n, Z);
        gmove(n, &n1);
        n1.op = OINDREG;