match.pd: Implement pattern from simplify_conversion_from_bitmask.

2014-11-10  Richard Biener  <rguenther@suse.de>

	* match.pd: Implement pattern from simplify_conversion_from_bitmask.
	* tree-ssa-forwprop.c (simplify_conversion_from_bitmask): Remove.
	(pass_forwprop::execute): Do not call simplify_conversion_from_bitmask.

From-SVN: r217284

gcc/ChangeLog

 2014-11-10  Richard Biener  <rguenther@suse.de>
 
+	* match.pd: Implement pattern from simplify_conversion_from_bitmask.
+	* tree-ssa-forwprop.c (simplify_conversion_from_bitmask): Remove.
+	(pass_forwprop::execute): Do not call simplify_conversion_from_bitmask.
+
+2014-11-10  Richard Biener  <rguenther@suse.de>
+
 	* match.pd: Move rest of the conversion combining patterns
 	from tree-ssa-forwprop.c.
 	* tree-ssa-forwprop.c (combine_conversions): Remove.

gcc/match.pd

@@ -431,3 +431,15 @@ along with GCC; see the file COPYING3.  If not see
 	(unsigned) significand_size (TYPE_MODE (inter_type))
 	>= inside_prec - !inside_unsignedp)
     (convert @0))))))
+
+/* If we have a narrowing conversion to an integral type that is fed by a
+   BIT_AND_EXPR, we might be able to remove the BIT_AND_EXPR if it merely
+   masks off bits outside the final type (and nothing else).  */
+(simplify
+  (convert (bit_and @0 INTEGER_CST@1))
+  (if (INTEGRAL_TYPE_P (type)
+       && INTEGRAL_TYPE_P (TREE_TYPE (@0))
+       && TYPE_PRECISION (type) <= TYPE_PRECISION (TREE_TYPE (@0))
+       && operand_equal_p (@1, build_low_bits_mask (TREE_TYPE (@1),
+						    TYPE_PRECISION (type)), 0))
+   (convert @0)))

gcc/tree-ssa-forwprop.c

@@ -1214,78 +1214,6 @@ bailout:
 }
 
 
-/* GSI_P points to a statement which performs a narrowing integral
-   conversion.
-
-   Look for cases like:
-
-     t = x & c;
-     y = (T) t;
-
-   Turn them into:
-
-     t = x & c;
-     y = (T) x;
-
-   If T is narrower than X's type and C merely masks off bits outside
-   of (T) and nothing else.
-
-   Normally we'd let DCE remove the dead statement.  But no DCE runs
-   after the last forwprop/combine pass, so we remove the obviously
-   dead code ourselves.
-
-   Return TRUE if a change was made, FALSE otherwise.  */
-
-static bool 
-simplify_conversion_from_bitmask (gimple_stmt_iterator *gsi_p)
-{
-  gimple stmt = gsi_stmt (*gsi_p);
-  gimple rhs_def_stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt));
-
-  /* See if the input for the conversion was set via a BIT_AND_EXPR and
-     the only use of the BIT_AND_EXPR result is the conversion.  */
-  if (is_gimple_assign (rhs_def_stmt)
-      && gimple_assign_rhs_code (rhs_def_stmt) == BIT_AND_EXPR
-      && has_single_use (gimple_assign_lhs (rhs_def_stmt)))
-    {
-      tree rhs_def_operand1 = gimple_assign_rhs1 (rhs_def_stmt);
-      tree rhs_def_operand2 = gimple_assign_rhs2 (rhs_def_stmt);
-      tree lhs_type = TREE_TYPE (gimple_assign_lhs (stmt));
-
-      /* Now verify suitability of the BIT_AND_EXPR's operands.
-	 The first must be an SSA_NAME that we can propagate and the
-	 second must be an integer constant that masks out all the
-	 bits outside the final result's type, but nothing else.  */
-      if (TREE_CODE (rhs_def_operand1) == SSA_NAME
-	  && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand1)
-	  && TREE_CODE (rhs_def_operand2) == INTEGER_CST
-	  && operand_equal_p (rhs_def_operand2,
-			      build_low_bits_mask (TREE_TYPE (rhs_def_operand2),
-			       			   TYPE_PRECISION (lhs_type)),
-						   0))
-	{
-	  /* This is an optimizable case.  Replace the source operand
-	     in the conversion with the first source operand of the
-	     BIT_AND_EXPR.  */
-	  gimple_assign_set_rhs1 (stmt, rhs_def_operand1);
-	  stmt = gsi_stmt (*gsi_p);
-	  update_stmt (stmt);
-
-	  /* There is no DCE after the last forwprop pass.  It's
-	     easy to clean up the first order effects here.  */
-	  gimple_stmt_iterator si;
-	  si = gsi_for_stmt (rhs_def_stmt);
-	  gsi_remove (&si, true);
-	  fwprop_invalidate_lattice (gimple_get_lhs (rhs_def_stmt));
-	  release_defs (rhs_def_stmt);
-	  return true;
-	}
-    }
-
-  return false;
-}
-
-
 /* Helper function for simplify_gimple_switch.  Remove case labels that
    have values outside the range of the new type.  */
 
@@ -2940,24 +2868,6 @@ pass_forwprop::execute (function *fun)
 			&& maybe_clean_or_replace_eh_stmt (stmt, stmt))
 		      bitmap_set_bit (to_purge, bb->index);
 		  }
-		else if (CONVERT_EXPR_CODE_P (code)
-			 || code == FLOAT_EXPR
-			 || code == FIX_TRUNC_EXPR)
-		  {
-		    /* If we have a narrowing conversion to an integral
-		       type that is fed by a BIT_AND_EXPR, we might be
-		       able to remove the BIT_AND_EXPR if it merely
-		       masks off bits outside the final type (and nothing
-		       else.  */
-		    tree outer_type = TREE_TYPE (gimple_assign_lhs (stmt));
-		    tree inner_type = TREE_TYPE (gimple_assign_rhs1 (stmt));
-		    if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
-			&& INTEGRAL_TYPE_P (outer_type)
-			&& INTEGRAL_TYPE_P (inner_type)
-			&& (TYPE_PRECISION (outer_type)
-			    <= TYPE_PRECISION (inner_type)))
-		      changed = simplify_conversion_from_bitmask (&gsi);
-		  }
 		else if (code == VEC_PERM_EXPR)
 		  {
 		    int did_something = simplify_permutation (&gsi);