MSP430: Emulate 16-bit shifts with rotate insn when src operand is in memory

MSP430: Emulate 16-bit shifts with rotate insn when src operand is in memory

gcc/ChangeLog

2019-06-06  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* config/msp430/msp430.md (ashlhi3): Force shift src operand into a
	register if it is in memory, so the shift can be emulated with a rotate
	instruction.
	(ashrhi3): Likewise.
	(lshrhi3): Likewise.

gcc/testsuite/ChangeLog

2019-06-06  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* gcc.target/msp430/emulate-slli.c: New test.
	* gcc.target/msp430/emulate-srai.c: New test.
	* gcc.target/msp430/emulate-srli.c: New test.

From-SVN: r271993