ifcvt: Allow constants for noce_convert_multiple.

This lifts the restriction of not allowing constants for
noce_convert_multiple.  The code later checks if a valid sequence
is produced anyway.

gcc/ChangeLog:

	* ifcvt.cc (noce_convert_multiple_sets): Allow constants.
	(bb_ok_for_noce_convert_multiple_sets): Likewise.

diff --git a/gcc/ifcvt.cc b/gcc/ifcvt.cc
index 0f7a126..c696563 100644 (file)
--- a/gcc/ifcvt.cc
+++ b/gcc/ifcvt.cc
@@ -3288,7 +3288,9 @@ noce_convert_multiple_sets (struct noce_if_info *if_info)
         we'll end up trying to emit r4:HI = cond ? (r1:SI) : (r3:HI).
         Wrap the two cmove operands into subregs if appropriate to prevent
         that.  */
-      if (GET_MODE (new_val) != GET_MODE (temp))
+
+      if (!CONSTANT_P (new_val)
+         && GET_MODE (new_val) != GET_MODE (temp))
        {
          machine_mode src_mode = GET_MODE (new_val);
          machine_mode dst_mode = GET_MODE (temp);
@@ -3299,7 +3301,8 @@ noce_convert_multiple_sets (struct noce_if_info *if_info)
            }
          new_val = lowpart_subreg (dst_mode, new_val, src_mode);
        }
-      if (GET_MODE (old_val) != GET_MODE (temp))
+      if (!CONSTANT_P (old_val)
+         && GET_MODE (old_val) != GET_MODE (temp))
        {
          machine_mode src_mode = GET_MODE (old_val);
          machine_mode dst_mode = GET_MODE (temp);
@@ -3441,9 +3444,9 @@ bb_ok_for_noce_convert_multiple_sets (basic_block test_bb)
       if (!REG_P (dest))
        return false;
 
-      if (!(REG_P (src)
-          || (GET_CODE (src) == SUBREG && REG_P (SUBREG_REG (src))
-              && subreg_lowpart_p (src))))
+      if (!((REG_P (src) || CONSTANT_P (src))
+           || (GET_CODE (src) == SUBREG && REG_P (SUBREG_REG (src))
+             && subreg_lowpart_p (src))))
        return false;
 
       /* Destination must be appropriate for a conditional write.  */