Fix assert in gimple_phi_arg

2017-07-19  Tom de Vries  <tom@codesourcery.com>

	* gimple.h (gimple_phi_arg): Make assert more strict.

From-SVN: r250351

gcc/ChangeLog

+2017-07-19  Tom de Vries  <tom@codesourcery.com>
+
+	* gimple.h (gimple_phi_arg): Make assert more strict.
+
 2017-07-19  Steven Munroe  <munroesj@gcc.gnu.org>
 
 	* config.gcc (powerpc*-*-*): Add mmintrin.h.

gcc/gimple.h

@@ -4341,7 +4341,7 @@ static inline struct phi_arg_d *
 gimple_phi_arg (gimple *gs, unsigned index)
 {
   gphi *phi_stmt = as_a <gphi *> (gs);
-  gcc_gimple_checking_assert (index <= phi_stmt->capacity);
+  gcc_gimple_checking_assert (index < phi_stmt->capacity);
   return &(phi_stmt->args[index]);
 }