Re: Move some bit and binary optimizations in simplify and match

["Hurugalawadi, Naveen" <Naveen.Hurugalawadi@caviumnetworks.com>]

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Hi,

Thanks very much for your detailed explanation regarding the queries.

>> you are missing the convert? on the lshift now, without it the
>> tree_nop_conversion_p check always evaluates to true.
Done.

>> fold-const.c which handles TRUTH_NOT_EXPR but logical_inverted_value
>> does not handle it.  I suggest to add
Done.

Please find attached the modified patch as per your suggestions.

>> You should move them to match.pd.  It requires duplication to
>> handle the const vs. non-const cases the fold-const.c code handled.

Have modified patterns to handle const and non-const cases.
Will test it and post it once finished with it.

Thanks,
Naveen

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diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index de45a2c..1e7fbb4 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -9803,20 +9803,6 @@ fold_binary_loc (location_t loc,
       goto associate;
 
     case MULT_EXPR:
-      /* (-A) * (-B) -> A * B  */
-      if (TREE_CODE (arg0) == NEGATE_EXPR && negate_expr_p (arg1))
-	return fold_build2_loc (loc, MULT_EXPR, type,
-			    fold_convert_loc (loc, type,
-					      TREE_OPERAND (arg0, 0)),
-			    fold_convert_loc (loc, type,
-					      negate_expr (arg1)));
-      if (TREE_CODE (arg1) == NEGATE_EXPR && negate_expr_p (arg0))
-	return fold_build2_loc (loc, MULT_EXPR, type,
-			    fold_convert_loc (loc, type,
-					      negate_expr (arg0)),
-			    fold_convert_loc (loc, type,
-					      TREE_OPERAND (arg1, 0)));
-
       if (! FLOAT_TYPE_P (type))
 	{
 	  /* Transform x * -C into -x * C if x is easily negatable.  */
@@ -9830,16 +9816,6 @@ fold_binary_loc (location_t loc,
 						  negate_expr (arg0)),
 				tem);
 
-	  /* (a * (1 << b)) is (a << b)  */
-	  if (TREE_CODE (arg1) == LSHIFT_EXPR
-	      && integer_onep (TREE_OPERAND (arg1, 0)))
-	    return fold_build2_loc (loc, LSHIFT_EXPR, type, op0,
-				TREE_OPERAND (arg1, 1));
-	  if (TREE_CODE (arg0) == LSHIFT_EXPR
-	      && integer_onep (TREE_OPERAND (arg0, 0)))
-	    return fold_build2_loc (loc, LSHIFT_EXPR, type, op1,
-				TREE_OPERAND (arg0, 1));
-
 	  /* (A + A) * C -> A * 2 * C  */
 	  if (TREE_CODE (arg0) == PLUS_EXPR
 	      && TREE_CODE (arg1) == INTEGER_CST
@@ -9882,21 +9858,6 @@ fold_binary_loc (location_t loc,
 	}
       else
 	{
-	  /* Convert (C1/X)*C2 into (C1*C2)/X.  This transformation may change
-             the result for floating point types due to rounding so it is applied
-             only if -fassociative-math was specify.  */
-	  if (flag_associative_math
-	      && TREE_CODE (arg0) == RDIV_EXPR
-	      && TREE_CODE (arg1) == REAL_CST
-	      && TREE_CODE (TREE_OPERAND (arg0, 0)) == REAL_CST)
-	    {
-	      tree tem = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 0),
-				      arg1);
-	      if (tem)
-		return fold_build2_loc (loc, RDIV_EXPR, type, tem,
-				    TREE_OPERAND (arg0, 1));
-	    }
-
           /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y.  */
 	  if (operand_equal_p (arg0, arg1, 0))
 	    {
@@ -10053,22 +10014,6 @@ fold_binary_loc (location_t loc,
       goto bit_rotate;
 
     case BIT_AND_EXPR:
-      /* ~X & X, (X == 0) & X, and !X & X are always zero.  */
-      if ((TREE_CODE (arg0) == BIT_NOT_EXPR
-	   || TREE_CODE (arg0) == TRUTH_NOT_EXPR
-	   || (TREE_CODE (arg0) == EQ_EXPR
-	       && integer_zerop (TREE_OPERAND (arg0, 1))))
-	  && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0))
-	return omit_one_operand_loc (loc, type, integer_zero_node, arg1);
-
-      /* X & ~X , X & (X == 0), and X & !X are always zero.  */
-      if ((TREE_CODE (arg1) == BIT_NOT_EXPR
-	   || TREE_CODE (arg1) == TRUTH_NOT_EXPR
-	   || (TREE_CODE (arg1) == EQ_EXPR
-	       && integer_zerop (TREE_OPERAND (arg1, 1))))
-	  && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
-	return omit_one_operand_loc (loc, type, integer_zero_node, arg0);
-
       /* Fold (X ^ 1) & 1 as (X & 1) == 0.  */
       if (TREE_CODE (arg0) == BIT_XOR_EXPR
 	  && INTEGRAL_TYPE_P (type)
diff --git a/gcc/match.pd b/gcc/match.pd
index f3813d8..1120c59 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -324,6 +324,22 @@ along with GCC; see the file COPYING3.  If not see
     (if (real_isinteger (&TREE_REAL_CST (@1), &n) && (n & 1) == 0)
      (pows @0 @1))))))
 
+/* Fold (a * (1 << b)) into (a << b)  */
+(simplify
+ (mult:c @0 (convert? (lshift integer_onep@1 @2)))
+  (if (! FLOAT_TYPE_P (type)
+       && tree_nop_conversion_p (type, TREE_TYPE (@1)))
+   (lshift @0 @2)))
+
+/* Fold (C1/X)*C2 into (C1*C2)/X.  */
+(simplify
+ (mult (rdiv:s REAL_CST@0 @1) REAL_CST@2)
+  (if (flag_associative_math)
+  (with
+   { tree tem = const_binop (MULT_EXPR, type, @0, @2); }
+  (if (tem)
+   (rdiv { tem; } @1)))))
+
 /* X % Y is smaller than Y.  */
 (for cmp (lt ge)
  (simplify
@@ -543,6 +559,13 @@ along with GCC; see the file COPYING3.  If not see
 (match negate_expr_p
  VECTOR_CST
  (if (FLOAT_TYPE_P (TREE_TYPE (type)) || TYPE_OVERFLOW_WRAPS (type))))
+
+/* (-A) * (-B) -> A * B  */
+(simplify
+ (mult:c (convert1? (negate @0)) (convert2? negate_expr_p@1))
+  (if (tree_nop_conversion_p (type, TREE_TYPE (@0))
+       && tree_nop_conversion_p (type, TREE_TYPE (@1)))
+   (mult (convert @0) (convert (negate @1)))))
  
 /* -(A + B) -> (-B) - A.  */
 (simplify
@@ -629,6 +652,8 @@ along with GCC; see the file COPYING3.  If not see
   (truth_not @0))
 
 (match (logical_inverted_value @0)
+ (truth_not @0))
+(match (logical_inverted_value @0)
  (bit_not truth_valued_p@0))
 (match (logical_inverted_value @0)
  (eq @0 integer_zerop))
@@ -646,6 +671,10 @@ along with GCC; see the file COPYING3.  If not see
  (simplify
   (op:c truth_valued_p@0 (logical_inverted_value @0))
   { constant_boolean_node (true, type); }))
+/* Simplify ~X & X as zero.  */
+(simplify
+ (bit_and:c (convert? truth_valued_p@0) (convert? (logical_inverted_value @0)))
+  { build_zero_cst (type); })
 /* X ==/!= !X is false/true.  */
 (for op (eq ne)
  (simplify