re PR middle-end/46637 (SIGSEGV in if_then_else_cond - too deep recursion)

	PR middle-end/46637
	* combine.c (try_combine): When substing i2dest for i2src, pass
	1 as last argument even if
	i0_feeds_i1_n && i1_feeds_i2_n && i0dest_in_i0src.

	* gcc.c-torture/compile/pr46637.c: New test.

From-SVN: r167148

gcc/ChangeLog

+2010-11-25  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/46637
+	* combine.c (try_combine): When substing i2dest for i2src, pass
+	1 as last argument even if
+	i0_feeds_i1_n && i1_feeds_i2_n && i0dest_in_i0src.
+
 2010-11-25  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR middle-end/46647

gcc/combine.c

@@ -3096,10 +3096,12 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int *new_direct_jump_p)
       /* If I1 feeds into I2 and I1DEST is in I1SRC, we need to make a unique
 	 copy of I2SRC each time we substitute it, in order to avoid creating
 	 self-referential RTL when we will be substituting I1SRC for I1DEST
-	 later.  Likewise if I0 feeds into I2 and I0DEST is in I0SRC.  */
+	 later.  Likewise if I0 feeds into I2, either directly or indirectly
+	 through I1, and I0DEST is in I0SRC.  */
       newpat = subst (PATTERN (i3), i2dest, i2src, 0,
 		      (i1_feeds_i2_n && i1dest_in_i1src)
-		      || (i0_feeds_i2_n && i0dest_in_i0src));
+		      || ((i0_feeds_i2_n || (i0_feeds_i1_n && i1_feeds_i2_n))
+			  && i0dest_in_i0src));
       substed_i2 = 1;
 
       /* Record whether I2's body now appears within I3's body.  */

gcc/testsuite/ChangeLog

+2010-11-25  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/46637
+	* gcc.c-torture/compile/pr46637.c: New test.
+
 2010-11-25  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* gfortran.dg/pr46519-1.f: Add -mtune=generic.

gcc/testsuite/gcc.c-torture/compile/pr46637.c

+/* PR middle-end/46637 */
+
+struct S { int s[5]; } *p;
+
+void
+foo (long x)
+{
+  long a = x == 1 ? 4L : 1L;
+  asm ("" : "+m" (p->s[a]));
+  p->s[0]++;
+}