diff --git a/src/cmd/5g/reg.c b/src/cmd/5g/reg.c
index b72b9c1657..93724d0326 100644
--- a/src/cmd/5g/reg.c
+++ b/src/cmd/5g/reg.c
@@ -1029,6 +1029,13 @@ prop(Reg *r, Bits ref, Bits cal)
 				ref.b[z] = 0;
 			}
 			break;
+
+		default:
+			// Work around for issue 1304:
+			// flush modified globals before each instruction.
+			for(z=0; z<BITS; z++)
+				cal.b[z] |= externs.b[z];
+			break;
 		}
 		for(z=0; z<BITS; z++) {
 			ref.b[z] = (ref.b[z] & ~r1->set.b[z]) |
diff --git a/src/cmd/6g/reg.c b/src/cmd/6g/reg.c
index 82a2ce3125..bed9f8da68 100644
--- a/src/cmd/6g/reg.c
+++ b/src/cmd/6g/reg.c
@@ -1085,6 +1085,13 @@ prop(Reg *r, Bits ref, Bits cal)
 				ref.b[z] = 0;
 			}
 			break;
+
+		default:
+			// Work around for issue 1304:
+			// flush modified globals before each instruction.
+			for(z=0; z<BITS; z++)
+				cal.b[z] |= externs.b[z];
+			break;
 		}
 		for(z=0; z<BITS; z++) {
 			ref.b[z] = (ref.b[z] & ~r1->set.b[z]) |
diff --git a/src/cmd/8g/reg.c b/src/cmd/8g/reg.c
index 4ff68625d2..29270c8203 100644
--- a/src/cmd/8g/reg.c
+++ b/src/cmd/8g/reg.c
@@ -968,6 +968,13 @@ prop(Reg *r, Bits ref, Bits cal)
 				ref.b[z] = 0;
 			}
 			break;
+
+		default:
+			// Work around for issue 1304:
+			// flush modified globals before each instruction.
+			for(z=0; z<BITS; z++)
+				cal.b[z] |= externs.b[z];
+			break;
 		}
 		for(z=0; z<BITS; z++) {
 			ref.b[z] = (ref.b[z] & ~r1->set.b[z]) |