Do not foward a branch to just after a loop exit before

loop optimization; this broke doloop detection.

From-SVN: r57260

gcc/ChangeLog

+2002-09-17  Dale Johannesen  <dalej@apple.com>
+	* cfgcleanup.c (try_forward_edges):  Do not forward a
+	branch to just after a loop exit before loop optimization;
+	this interfered with doloop detection.
+
 2002-09-17  Nick Clifton  <nickc@redhat.com>
 
 	* config/arm/arm.c (output_return_instruction): Do not
@@ -118,6 +123,7 @@ Tue Sep 17 13:40:13 2002  Nicola Pero  <n.pero@mi.flashnet.it>
 	* real.h (real_nan): Return bool.
 	* doc/extend.texi: Document new builtins.
 
+>>>>>>> 1.15460
 2002-09-16  Jason Merrill  <jason@redhat.com>
 	    Danny Smith  <dannysmith@users.sourceforge.net>
 

gcc/cfgcleanup.c

@@ -515,6 +515,15 @@ try_forward_edges (mode, b)
 
 	      if (GET_CODE (insn) == NOTE)
 		break;
+
+	      /* Do not clean up branches to just past the end of a loop
+		 at this time; it can mess up the loop optimizer's
+		 recognition of some patterns. */
+
+	      insn = PREV_INSN (target->head);
+	      if (insn && GET_CODE (insn) == NOTE
+		    && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
+		break;
 	    }
 
 	  counter++;

gcc/testsuite/gcc.dg/doloop-1.c

+/* Make sure both loops are recognized as doloops.
+   If so, "bdnz" will be generated on ppc; if not,
+   you will get "ble". */
+
+/* { dg-do compile { target powerpc-*-* } } */
+/* { dg-options "-O2" } */
+void foo (int count, char* pca, char* pcb) {
+    int i;
+    if (count > 10)
+        for (i = 0; i < count; ++i)
+            pcb += i;
+    else
+        for (i = 0; i < count; ++i)
+            pca += i;
+    *pca = *pcb;
+}
+/* { dg-final { scan-assembler "bdnz" } } */
+/* { dg-final { scan-assembler-not "blt" } } */