diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ec354394aa8..d8443197009 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Mon Aug  2 23:46:45 1999  J"orn Rennecke <amylaar@cygnus.co.uk>
+
+	* loop.c (strength_reduce): When doing biv->giv conversion, fix up
+	reg_biv_class.
+
 1999-08-02  Jakub Jelinek  <jj@ultra.linux.cz>
 
 	* config/float-sparc.h: New file.
diff --git a/gcc/loop.c b/gcc/loop.c
index db50a1862e5..0b02cc2a41c 100644
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -4072,6 +4072,7 @@ strength_reduce (scan_start, end, loop_top, insn_count,
 		fprintf (loop_dump_stream, "is giv of biv %d\n", bl2->regno);
 	      /* Let this giv be discovered by the generic code.  */
 	      REG_IV_TYPE (bl->regno) = UNKNOWN_INDUCT;
+	      reg_biv_class[bl->regno] = NULL_PTR;
 	      /* We can get better optimization if we can move the giv setting
 		 before the first giv use.  */
 	      if (dominator
@@ -4123,7 +4124,13 @@ strength_reduce (scan_start, end, loop_top, insn_count,
 		}
 	      /* Remove this biv from the chain.  */
 	      if (bl->next)
-		*bl = *bl->next;
+		{
+		  /* We move the following giv from *bl->next into *bl.
+		     We have to update reg_biv_class for that moved biv
+		     to point to its new address.  */
+		  *bl = *bl->next;
+		  reg_biv_class[bl->regno] = bl;
+		}
 	      else
 		{
 		  *backbl = 0;