combine.c (known_cond): Do not reverse the condition when SMAX/UMAX is being considered and the...

        * combine.c (known_cond): Do not reverse the condition when
        SMAX/UMAX is being considered and the condition is for equality
        or inequality.

        * testsuite/gcc.c-torture/execute/20010221-1.c: New test.

From-SVN: r40077

gcc/ChangeLog

+2001-02-26  Jason Eckhardt  <jle@redhat.com>
+
+	* combine.c (known_cond): Do not reverse the condition when
+	SMAX/UMAX is being considered and the condition is for equality 
+	or inequality.
+
+	* testsuite/gcc.c-torture/execute/20010221-1.c: New test.
+
 2001-02-26  Philip Blundell  <philb@gnu.org>
 
 	* config.gcc: Remove obsolete targets "arm*-*-linuxoldld" and

gcc/combine.c

@@ -7512,7 +7512,12 @@ known_cond (x, cond, reg, val)
 	    {
 	      int unsignedp = (code == UMIN || code == UMAX);
 
-	      if (code == SMAX || code == UMAX)
+	      /* Do not reverse the condition when it is NE or EQ.
+		 This is because we cannot conclude anything about
+		 the value of 'SMAX (x, y)' when x is not equal to y,
+		 but we can when x equals y.  */ 
+	      if ((code == SMAX || code == UMAX)
+		  && ! (cond == EQ || cond == NE))
 		cond = reverse_condition (cond);
 
 	      switch (cond)

gcc/testsuite/gcc.c-torture/execute/20010221-1.c

+
+int n = 2;
+
+main ()
+{
+  int i, x = 45;
+
+  for (i = 0; i < n; i++)
+    {
+      if (i != 0)
+	x = ( i > 0 ) ? i : 0;
+    }
+
+  if (x != 1)
+    abort ();
+  exit (0);
+}