[30/77] Use scalar_int_mode for doubleword splits

[Richard Sandiford <richard.sandiford@linaro.org>]

This patch uses is_a <scalar_int_mode> in a couple of places that
were splitting doubleword integer operations into word_mode
operations.  It also uses scalar_int_mode in the expand_expr_real_2
handling of doubleword shifts.

2017-07-13  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* expr.c (expand_expr_real_2): Use scalar_int_mode for the
	double-word mode.
	* lower-subreg.c (resolve_shift_zext): Use is_a <scalar_int_mode>.
	* optabs.c (expand_unop): Likewise.

Index: gcc/expr.c
===================================================================
--- gcc/expr.c	2017-07-13 09:18:35.048126637 +0100
+++ gcc/expr.c	2017-07-13 09:18:36.841969327 +0100
@@ -8201,6 +8201,7 @@ expand_expr_real_2 (sepops ops, rtx targ
   tree type;
   int unsignedp;
   machine_mode mode;
+  scalar_int_mode int_mode;
   enum tree_code code = ops->code;
   optab this_optab;
   rtx subtarget, original_target;
@@ -9165,8 +9166,8 @@ #define REDUCE_BIT_FIELD(expr)	(reduce_b
 	if (code == LSHIFT_EXPR
 	    && target
 	    && REG_P (target)
-	    && mode == GET_MODE_WIDER_MODE (word_mode).else_void ()
-	    && GET_MODE_SIZE (mode) == 2 * GET_MODE_SIZE (word_mode)
+	    && GET_MODE_2XWIDER_MODE (word_mode).exists (&int_mode)
+	    && mode == int_mode
 	    && TREE_CONSTANT (treeop1)
 	    && TREE_CODE (treeop0) == SSA_NAME)
 	  {
@@ -9177,20 +9178,20 @@ #define REDUCE_BIT_FIELD(expr)	(reduce_b
 		machine_mode rmode = TYPE_MODE
 		  (TREE_TYPE (gimple_assign_rhs1 (def)));
 
-		if (GET_MODE_SIZE (rmode) < GET_MODE_SIZE (mode)
+		if (GET_MODE_SIZE (rmode) < GET_MODE_SIZE (int_mode)
 		    && TREE_INT_CST_LOW (treeop1) < GET_MODE_BITSIZE (word_mode)
 		    && ((TREE_INT_CST_LOW (treeop1) + GET_MODE_BITSIZE (rmode))
 			>= GET_MODE_BITSIZE (word_mode)))
 		  {
 		    rtx_insn *seq, *seq_old;
 		    unsigned int high_off = subreg_highpart_offset (word_mode,
-								    mode);
+								    int_mode);
 		    bool extend_unsigned
 		      = TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def)));
-		    rtx low = lowpart_subreg (word_mode, op0, mode);
-		    rtx dest_low = lowpart_subreg (word_mode, target, mode);
+		    rtx low = lowpart_subreg (word_mode, op0, int_mode);
+		    rtx dest_low = lowpart_subreg (word_mode, target, int_mode);
 		    rtx dest_high = simplify_gen_subreg (word_mode, target,
-							 mode, high_off);
+							 int_mode, high_off);
 		    HOST_WIDE_INT ramount = (BITS_PER_WORD
 					     - TREE_INT_CST_LOW (treeop1));
 		    tree rshift = build_int_cst (TREE_TYPE (treeop1), ramount);
@@ -9213,12 +9214,13 @@ #define REDUCE_BIT_FIELD(expr)	(reduce_b
 		    end_sequence ();
 		    temp = target ;
 
-		    if (have_insn_for (ASHIFT, mode))
+		    if (have_insn_for (ASHIFT, int_mode))
 		      {
 			bool speed_p = optimize_insn_for_speed_p ();
 			start_sequence ();
-			rtx ret_old = expand_variable_shift (code, mode, op0,
-							     treeop1, target,
+			rtx ret_old = expand_variable_shift (code, int_mode,
+							     op0, treeop1,
+							     target,
 							     unsignedp);
 
 			seq_old = get_insns ();
Index: gcc/lower-subreg.c
===================================================================
--- gcc/lower-subreg.c	2017-07-13 09:18:29.217658709 +0100
+++ gcc/lower-subreg.c	2017-07-13 09:18:36.841969327 +0100
@@ -1219,6 +1219,7 @@ resolve_shift_zext (rtx_insn *insn)
   rtx_insn *insns;
   rtx src_reg, dest_reg, dest_upper, upper_src = NULL_RTX;
   int src_reg_num, dest_reg_num, offset1, offset2, src_offset;
+  scalar_int_mode inner_mode;
 
   set = single_set (insn);
   if (!set)
@@ -1232,6 +1233,8 @@ resolve_shift_zext (rtx_insn *insn)
     return NULL;
 
   op_operand = XEXP (op, 0);
+  if (!is_a <scalar_int_mode> (GET_MODE (op_operand), &inner_mode))
+    return NULL;
 
   /* We can tear this operation apart only if the regs were already
      torn apart.  */
@@ -1244,8 +1247,7 @@ resolve_shift_zext (rtx_insn *insn)
   src_reg_num = (GET_CODE (op) == LSHIFTRT || GET_CODE (op) == ASHIFTRT)
 		? 1 : 0;
 
-  if (WORDS_BIG_ENDIAN
-      && GET_MODE_SIZE (GET_MODE (op_operand)) > UNITS_PER_WORD)
+  if (WORDS_BIG_ENDIAN && GET_MODE_SIZE (inner_mode) > UNITS_PER_WORD)
     src_reg_num = 1 - src_reg_num;
 
   if (GET_CODE (op) == ZERO_EXTEND)
Index: gcc/optabs.c
===================================================================
--- gcc/optabs.c	2017-07-13 09:18:35.049126549 +0100
+++ gcc/optabs.c	2017-07-13 09:18:36.842969240 +0100
@@ -2736,22 +2736,24 @@ expand_unop (machine_mode mode, optab un
     }
 
   if (unoptab == popcount_optab
-      && GET_MODE_SIZE (mode) == 2 * UNITS_PER_WORD
+      && is_a <scalar_int_mode> (mode, &int_mode)
+      && GET_MODE_SIZE (int_mode) == 2 * UNITS_PER_WORD
       && optab_handler (unoptab, word_mode) != CODE_FOR_nothing
       && optimize_insn_for_speed_p ())
     {
-      temp = expand_doubleword_popcount (mode, op0, target);
+      temp = expand_doubleword_popcount (int_mode, op0, target);
       if (temp)
 	return temp;
     }
 
   if (unoptab == parity_optab
-      && GET_MODE_SIZE (mode) == 2 * UNITS_PER_WORD
+      && is_a <scalar_int_mode> (mode, &int_mode)
+      && GET_MODE_SIZE (int_mode) == 2 * UNITS_PER_WORD
       && (optab_handler (unoptab, word_mode) != CODE_FOR_nothing
 	  || optab_handler (popcount_optab, word_mode) != CODE_FOR_nothing)
       && optimize_insn_for_speed_p ())
     {
-      temp = expand_doubleword_parity (mode, op0, target);
+      temp = expand_doubleword_parity (int_mode, op0, target);
       if (temp)
 	return temp;
     }