From: Donn Seeley <donn@ucbvax.Berkeley.EDU>
Date: Sat, 16 Jan 1988 11:24:28 +0000 (-0800)
Subject: In bflow(), it was possible to inadvertently delete an instruction that
X-Git-Tag: BSD-4_3_Net_1-Snapshot-Development~2678
X-Git-Url: https://git.subgeniuskitty.com/unix-history/.git/commitdiff_plain/e0921d75160a6f36e16b90aff41f8e1a4b098705

In bflow(), it was possible to inadvertently delete an instruction that
writes into a temporary register because it was examined a second time for
writes to a dead register after a preceding instruction was deleted.  I fixed
this by forcing a return after the first deletion.  There are probably more
bugs like this lurking in bflow()...

SCCS-vsn: old/pcc/c2.tahoe/c21.c 1.6
---

diff --git a/usr/src/old/pcc/c2.tahoe/c21.c b/usr/src/old/pcc/c2.tahoe/c21.c
index 776178dc36..5988699f63 100644
--- a/usr/src/old/pcc/c2.tahoe/c21.c
+++ b/usr/src/old/pcc/c2.tahoe/c21.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static char sccsid[] = "@(#)c21.c	1.5 (Berkeley/CCI) %G%";
+static char sccsid[] = "@(#)c21.c	1.6 (Berkeley/CCI) %G%";
 #endif
 
 /*
@@ -650,7 +650,8 @@ bflow(p)
 				if (tempreg(src,r2))
 					uses[r2]=uses[r], uses[r]=0;
 				redun3(p);
-				newcode(p); redunm++; flow=r;
+				newcode(p); redunm++;
+				return(p);	/* avoid stale uses[] data */
 			} else
 				splitrand(p);
 		}