i386: Do not use explicit operands for MOVS instructions [PR120019]

i386: Do not use explicit operands for MOVS instructions [PR120019]

Some assemblers do not support MOVS instructions with explicit operands.
Emit instruction with implicit operands, but prefix the instruction with a
segment override prefix if the memory operand refers to ADDR_SPACE_SEG_FS
or ADDR_SPACE_SEG_GS named address space.

	PR target/120019

gcc/ChangeLog:

	* config/i386/i386.cc (ix86_print_operand): Handle 'v' operand
	modifier to emit segment override prefix.
	* config/i386/i386.md (*strmovdi_rex_1): Use %v operand modifier
	to emit segment override prefix.
	(*strmovsi_1): Ditto.
	(*strmovhi_1): Ditto.
	(*strmovqi_1): Ditto.
	(*rep_movdi_rex64): Ditto.
	(*rep_movsi): Ditto.
	(*rep_movqi): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr111657-1.c (dg-do): Change to "assemble".
	(dg-options): Remove -masm=att and add -save-temps.
	(dg-final): Update scan-assembler and scan-assembler-not strings.

Co-authored-by: Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>