re PR target/93141 (Missed optimization : Use of adc when checking overflow)

re PR target/93141 (Missed optimization : Use of adc when checking overflow)

	PR target/93141
	* config/i386/i386.md (subv<mode>4): Use SWIDWI iterator instead of
	SWI.  Use <general_hilo_operand> instead of <general_operand>.  Use
	CONST_SCALAR_INT_P instead of CONST_INT_P.
	(*subv<mode>4_1): Rename to ...
	(subv<mode>4_1): ... this.
	(*subv<dwi>4_doubleword, *addv<dwi>4_doubleword_1): New
	define_insn_and_split patterns.
	(*subv<mode>4_overflow_1, *addv<mode>4_overflow_2): New define_insn
	patterns.

	* gcc.target/i386/pr93141-1.c: Add tests with constants that have MSB
	of the low half of the constant set.
	* gcc.target/i386/pr93141-2.c: New test.

From-SVN: r280029