From 0cd7d8826ebc37c4f1962fa15a4701ac468dd0ed Mon Sep 17 00:00:00 2001
From: sater <none@none>
Date: Sat, 19 May 1984 11:49:01 +0000
Subject: [PATCH] erase(reg) now also erases all register whose contents depend
 on the contents of reg.

---
 mach/proto/cg/reg.c | 42 ++++++++++++++++++++++++++++++++----------
 1 file changed, 32 insertions(+), 10 deletions(-)

diff --git a/mach/proto/cg/reg.c b/mach/proto/cg/reg.c
index 0e10ab8bf..4482dce10 100644
--- a/mach/proto/cg/reg.c
+++ b/mach/proto/cg/reg.c
@@ -71,23 +71,45 @@ getrefcount(regno) {
 
 erasereg(regno) {
 	register struct reginfo *rp;
-	register i;
 
 #if MAXMEMBERS==0
-	rp= &machregs[regno];
-	rp->r_contents.t_token = 0;
-	for (i=0;i<TOKENSIZE;i++)
-		rp->r_contents.t_att[i].aw=0;
+	awayreg(regno);
 #else
 	for (rp=machregs;rp<machregs+NREGS;rp++)
-		if (rp->r_clash[regno>>4]&(1<<(regno&017))) {
-			rp->r_contents.t_token = 0;
-			for (i=0;i<TOKENSIZE;i++)
-				rp->r_contents.t_att[i].aw=0;
-		}
+		if (rp->r_clash[regno>>4]&(1<<(regno&017)))
+			awayreg(rp-machregs);
 #endif
 }
 
+awayreg(regno) {
+	register struct reginfo *rp;
+	register tkdef_p tdp;
+	register i;
+
+	rp = &machregs[regno];
+	rp->r_contents.t_token = 0;
+	for (i=0;i<TOKENSIZE;i++)
+		rp->r_contents.t_att[i].aw = 0;
+
+	/* Now erase recursively all registers containing
+	 * something using this one
+	 */
+	for (rp=machregs;rp<machregs+NREGS;rp++) {
+		if (rp->r_contents.t_token == -1) {
+			if (rp->r_contents.t_att[0].ar == regno)
+				erasereg(rp-machregs);
+		} else {
+			tdp= & tokens[rp->r_contents.t_token];
+			for (i=0;i<TOKENSIZE;i++)
+				if (tdp->t_type[i] == EV_REG && 
+				    rp->r_contents.t_att[i].ar == regno) {
+					erasereg(rp-machregs);
+					break;
+				}
+		}
+	}
+}
+
 cleanregs() {
 	register struct reginfo *rp;
 	register i;