[wide-int] Fix mask inversions in expand_copysign_bit

[Richard Sandiford]

At some point the original "~"s got straightened to "-"s.

Tested on powerpc64-linux-gnu and x86_64-linux-gnu.  This fixed
a testsuite difference in bfin-elf.  Applied as obvious.

Thanks,
Richard


Index: gcc/optabs.c
===================================================================
--- gcc/optabs.c        (revision 204311)
+++ gcc/optabs.c        (working copy)
@@ -3678,7 +3678,7 @@
              if (!op0_is_abs)
                op0_piece
                  = expand_binop (imode, and_optab, op0_piece,
-                                 immed_wide_int_const (-mask, imode),
+                                 immed_wide_int_const (~mask, imode),
                                  NULL_RTX, 1, OPTAB_LIB_WIDEN);
              op1 = expand_binop (imode, and_optab,
                                  operand_subword_force (op1, i, mode),
@@ -3708,7 +3708,7 @@
       op0 = gen_lowpart (imode, op0);
       if (!op0_is_abs)
        op0 = expand_binop (imode, and_optab, op0,
-                           immed_wide_int_const (-mask, imode),
+                           immed_wide_int_const (~mask, imode),
                            NULL_RTX, 1, OPTAB_LIB_WIDEN);
       temp = expand_binop (imode, ior_optab, op0, op1,
                           gen_lowpart (imode, target), 1, OPTAB_LIB_WIDEN);