Move min(max...) and max(min...) folds to match.pd

This handles both integer and floating-point arguments.  It's needed
for the follow-on patch to move fmin and fmax to match.pd.

Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.

gcc/
	* fold-const.c (fold_minmax): Delete.
	(fold_binary_loc): Don't call it.
	* match.pd: Add rules previously handled by fold_minmax.

From-SVN: r229430

3 files changed, 14 insertions, 51 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 06b27fa..1066861 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2015-10-27  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* fold-const.c (fold_minmax): Delete.
+	(fold_binary_loc): Don't call it.
+	* match.pd: Add rules previously handled by fold_minmax.
+
+2015-10-27  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* builtins.c (fold_builtin_fma): Remove constant handling.
 	(fold_builtin_3): Handle constant fma arguments here.
 
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index ffad732..e8ff1de 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -8073,49 +8073,6 @@ fold_truth_andor (location_t loc, enum tree_code code, tree type,
   return NULL_TREE;
 }
 
-/* Fold a binary expression of code CODE and type TYPE with operands
-   OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
-   Return the folded expression if folding is successful.  Otherwise,
-   return NULL_TREE.  */
-
-static tree
-fold_minmax (location_t loc, enum tree_code code, tree type, tree op0, tree op1)
-{
-  enum tree_code compl_code;
-
-  if (code == MIN_EXPR)
-    compl_code = MAX_EXPR;
-  else if (code == MAX_EXPR)
-    compl_code = MIN_EXPR;
-  else
-    gcc_unreachable ();
-
-  /* MIN (MAX (a, b), b) == b.  */
-  if (TREE_CODE (op0) == compl_code
-      && operand_equal_p (TREE_OPERAND (op0, 1), op1, 0))
-    return omit_one_operand_loc (loc, type, op1, TREE_OPERAND (op0, 0));
-
-  /* MIN (MAX (b, a), b) == b.  */
-  if (TREE_CODE (op0) == compl_code
-      && operand_equal_p (TREE_OPERAND (op0, 0), op1, 0)
-      && reorder_operands_p (TREE_OPERAND (op0, 1), op1))
-    return omit_one_operand_loc (loc, type, op1, TREE_OPERAND (op0, 1));
-
-  /* MIN (a, MAX (a, b)) == a.  */
-  if (TREE_CODE (op1) == compl_code
-      && operand_equal_p (op0, TREE_OPERAND (op1, 0), 0)
-      && reorder_operands_p (op0, TREE_OPERAND (op1, 1)))
-    return omit_one_operand_loc (loc, type, op0, TREE_OPERAND (op1, 1));
-
-  /* MIN (a, MAX (b, a)) == a.  */
-  if (TREE_CODE (op1) == compl_code
-      && operand_equal_p (op0, TREE_OPERAND (op1, 1), 0)
-      && reorder_operands_p (op0, TREE_OPERAND (op1, 0)))
-    return omit_one_operand_loc (loc, type, op0, TREE_OPERAND (op1, 0));
-
-  return NULL_TREE;
-}
-
 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
    by changing CODE to reduce the magnitude of constants involved in
    ARG0 of the comparison.
@@ -10426,15 +10383,7 @@ fold_binary_loc (location_t loc,
       return NULL_TREE;
 
     case MIN_EXPR:
-      tem = fold_minmax (loc, MIN_EXPR, type, arg0, arg1);
-      if (tem)
-	return tem;
-      goto associate;
-
     case MAX_EXPR:
-      tem = fold_minmax (loc, MAX_EXPR, type, arg0, arg1);
-      if (tem)
-	return tem;
       goto associate;
 
     case TRUTH_ANDIF_EXPR:
diff --git a/gcc/match.pd b/gcc/match.pd
index ca393e8..8de7987 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -1176,6 +1176,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (simplify
   (minmax @0 @0)
   @0))
+/* min(max(x,y),y) -> y.  */
+(simplify
+ (min:c (max:c @0 @1) @1)
+ @1)
+/* max(min(x,y),y) -> y.  */
+(simplify
+ (max:c (min:c @0 @1) @1)
+ @1)
 (simplify
  (min @0 @1)
  (if (INTEGRAL_TYPE_P (type)