From: ebotcazou <ebotcazou@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Tue, 22 Jan 2008 22:27:47 +0000 (+0000)
Subject: 	PR rtl-optimization/34628
X-Git-Tag: upstream/4.9.2~44031
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3888eedd894b7bfb3b3080e59ff66f6091a3fdc9;p=platform%2Fupstream%2Flinaro-gcc.git

	PR rtl-optimization/34628
	* combine.c (try_combine): Stop and undo after the first combination
	if an autoincrement side-effect on the first insn has effectively
	been lost.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@131744 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f882548..b59acd5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2008-01-22  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR rtl-optimization/34628
+	* combine.c (try_combine): Stop and undo after the first combination
+	if an autoincrement side-effect on the first insn has effectively
+	been lost.
+
 2008-01-22  David Edelsohn  <edelsohn@gnu.org>
 
 	PR target/34529
diff --git a/gcc/combine.c b/gcc/combine.c
index 43623a4..5cfa305 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -2751,12 +2751,17 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
 
   if (i1 && GET_CODE (newpat) != CLOBBER)
     {
-      /* Before we can do this substitution, we must redo the test done
-	 above (see detailed comments there) that ensures  that I1DEST
-	 isn't mentioned in any SETs in NEWPAT that are field assignments.  */
-
-      if (! combinable_i3pat (NULL_RTX, &newpat, i1dest, NULL_RTX,
-			      0, (rtx*) 0))
+      /* Check that an autoincrement side-effect on I1 has not been lost.
+	 This happens if I1DEST is mentioned in I2 and dies there, and
+	 has disappeared from the new pattern.  */
+      if ((FIND_REG_INC_NOTE (i1, NULL_RTX) != 0
+	   && !i1_feeds_i3
+	   && dead_or_set_p (i2, i1dest)
+	   && !reg_overlap_mentioned_p (i1dest, newpat))
+	  /* Before we can do this substitution, we must redo the test done
+	     above (see detailed comments there) that ensures  that I1DEST
+	     isn't mentioned in any SETs in NEWPAT that are field assignments.  */
+          || !combinable_i3pat (NULL_RTX, &newpat, i1dest, NULL_RTX, 0, 0))
 	{
 	  undo_all ();
 	  return 0;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 255201a..4ae4df9 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2008-01-22  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc.c-torture/execute/20080122-1.c: New test.
+
 2008-01-22  Tom Tromey  <tromey@redhat.com>
 
 	PR c++/34859:
diff --git a/gcc/testsuite/gcc.c-torture/execute/20080122-1.c b/gcc/testsuite/gcc.c-torture/execute/20080122-1.c
new file mode 100644
index 0000000..a2f7fed
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20080122-1.c
@@ -0,0 +1,35 @@
+/* PR rtl-optimization/34628 */
+/* Origin: Martin Michlmayr <tbm@cyrius.com> */
+
+typedef unsigned short u16;
+typedef unsigned char u8;
+
+static void
+do_segfault(u8 in_buf[], const u8 out_buf[], const int len)
+{
+  int i;
+
+  for (i = 0; i < len; i++) {
+    asm("");
+
+    in_buf[2*i] = (   out_buf[2*i] | out_buf[(2*i)+1]<<8  ) & 0xFF;
+
+    asm("");
+
+    in_buf[(2*i)+1] =  ( out_buf[2*i] | out_buf[(2*i)+1]<<8 ) >> 8;
+
+    asm("");
+  }
+}
+
+int main(int argc, char *argv[])
+{
+  u8 outbuf[32] = "buffer     ";
+  u8 inbuf[32] = "\f";
+
+  asm("");
+  do_segfault(inbuf, outbuf, 12);
+  asm("");
+
+  return 0;
+}