i386: Fix signed integer overflow in ix86_expand_int_movcc [PR120604]

i386: Fix signed integer overflow in ix86_expand_int_movcc [PR120604]

Patch for PR120553 enabled full 64-bit DImode immediates in
ix86_expand_int_movcc.  However, the function calculates the difference
between two immediate arguments using signed 64-bit HOST_WIDE_INT
subtractions that can cause signed integer overflow.

Avoid the overflow by casting operands of subtractions to
(unsigned HOST_WIDE_INT).

	PR target/120604

gcc/ChangeLog:

	* config/i386/i386-expand.cc (ix86_expand_int_movcc): Cast operands of
	signed 64-bit HOST_WIDE_INT subtractions to (unsigned HOST_WIDE_INT).