From: Jason Merrill <jason@redhat.com>
Date: Tue, 25 Mar 2003 20:23:25 +0000 (-0500)
Subject: re PR rtl-optimization/10171 (wrong code for inlined function)
X-Git-Tag: releases/gcc-3.2.3~70
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bb39b9627c28d8831568c5f7d738ad23df583d07;p=thirdparty%2Fgcc.git

re PR rtl-optimization/10171 (wrong code for inlined function)

        PR optimization/10171
        * unroll.c (unroll_loop): Don't delete the jump at the end unless
        we also delete a jump at the beginning.

From-SVN: r64862
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4facc063b519..ebdd20c98d54 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2003-03-25  Jason Merrill  <jason@redhat.com>
+
+	PR optimization/10171
+	* unroll.c (unroll_loop): Don't delete the jump at the end unless
+	we also delete a jump at the beginning.
+
 2003-03-25  Gerald Pfeifer  <pfeifer@dbai.tuwien.ac.at>
 
 	* doc/passes.texi (Passes): Properly document that we do not
diff --git a/gcc/unroll.c b/gcc/unroll.c
index b9232274add6..7c2425653233 100644
--- a/gcc/unroll.c
+++ b/gcc/unroll.c
@@ -353,9 +353,11 @@ unroll_loop (loop, insn_count, strength_reduce_p)
 	 jump to the loop condition.  Make sure to delete the jump
 	 insn, otherwise the loop body will never execute.  */
 
+      /* FIXME this actually checks for a jump to the continue point, which
+	 is not the same as the condition in a for loop.  As a result, this
+	 optimization fails for most for loops.  We should really use flow
+	 information rather than instruction pattern matching.  */
       rtx ujump = ujump_to_loop_cont (loop->start, loop->cont);
-      if (ujump)
-	delete_related_insns (ujump);
 
       /* If number of iterations is exactly 1, then eliminate the compare and
 	 branch at the end of the loop since they will never be taken.
@@ -367,9 +369,10 @@ unroll_loop (loop, insn_count, strength_reduce_p)
       if (GET_CODE (last_loop_insn) == BARRIER)
 	{
 	  /* Delete the jump insn.  This will delete the barrier also.  */
-	  delete_related_insns (PREV_INSN (last_loop_insn));
+	  last_loop_insn = PREV_INSN (last_loop_insn);
 	}
-      else if (GET_CODE (last_loop_insn) == JUMP_INSN)
+
+      if (ujump && GET_CODE (last_loop_insn) == JUMP_INSN)
 	{
 #ifdef HAVE_cc0
 	  rtx prev = PREV_INSN (last_loop_insn);
@@ -381,24 +384,27 @@ unroll_loop (loop, insn_count, strength_reduce_p)
 	  if (only_sets_cc0_p (prev))
 	    delete_related_insns (prev);
 #endif
-	}
 
-      /* Remove the loop notes since this is no longer a loop.  */
-      if (loop->vtop)
-	delete_related_insns (loop->vtop);
-      if (loop->cont)
-	delete_related_insns (loop->cont);
-      if (loop_start)
-	delete_related_insns (loop_start);
-      if (loop_end)
-	delete_related_insns (loop_end);
+	  delete_related_insns (ujump);
 
-      return;
+	  /* Remove the loop notes since this is no longer a loop.  */
+	  if (loop->vtop)
+	    delete_related_insns (loop->vtop);
+	  if (loop->cont)
+	    delete_related_insns (loop->cont);
+	  if (loop_start)
+	    delete_related_insns (loop_start);
+	  if (loop_end)
+	    delete_related_insns (loop_end);
+
+	  return;
+	}
     }
-  else if (loop_info->n_iterations > 0
-	   /* Avoid overflow in the next expression.  */
-	   && loop_info->n_iterations < MAX_UNROLLED_INSNS
-	   && loop_info->n_iterations * insn_count < MAX_UNROLLED_INSNS)
+
+  if (loop_info->n_iterations > 0
+      /* Avoid overflow in the next expression.  */
+      && loop_info->n_iterations < MAX_UNROLLED_INSNS
+      && loop_info->n_iterations * insn_count < MAX_UNROLLED_INSNS)
     {
       unroll_number = loop_info->n_iterations;
       unroll_type = UNROLL_COMPLETELY;