re PR target/51408 (Miscompilation in arm.md:*minmax_arithsi)

gcc/
	PR target/51408
	* config/arm/arm.md (*minmax_arithsi): Always require the else
	clause in the MINUS case.

gcc/testsuite/
	PR target/51408
	* gcc.dg/pr51408.c: New.

From-SVN: r182014

gcc/ChangeLog

+2011-12-05  Kazu Hirata  <kazu@codesourcery.com>
+
+	PR target/51408
+	* config/arm/arm.md (*minmax_arithsi): Always require the else
+	clause in the MINUS case.
+
 2011-12-05  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/50904

gcc/config/arm/arm.md

@@ -3413,7 +3413,7 @@
     bool need_else;
 
     if (which_alternative != 0 || operands[3] != const0_rtx
-        || (code != PLUS && code != MINUS && code != IOR && code != XOR))
+        || (code != PLUS && code != IOR && code != XOR))
       need_else = true;
     else
       need_else = false;

gcc/testsuite/ChangeLog

+2011-12-05  Kazu Hirata  <kazu@codesourcery.com>
+
+	PR target/51408
+	* gcc.dg/pr51408.c: New.
+
 2011-12-05  Jason Merrill  <jason@redhat.com>
 
 	* g++.dg/cpp0x/dc6.C: New.

gcc/testsuite/gcc.dg/pr51408.c

+/* This testcase used to fail because of a bug in 
+   arm.md:*minmax_arithsi.  */
+
+/* { dg-do run } */
+/* { dg-options "-O1" } */
+
+extern void abort (void);
+
+int __attribute__((noinline))
+foo (int a, int b)
+{
+  int max = (b > 0) ? b : 0;
+  return max - a;
+}
+
+int
+main (void)
+{
+  if (foo (3, -1) != -3)
+    abort ();
+  return 0;
+}