[COMMITTED][MSP430] Fix postinc addressing mode being used for dst operand of CMP insns

[Jeff Law]

On 12/5/19 4:32 AM, Jozef Lawrynowicz wrote:
> MSP430 RTL patterns for conditional branch instructions allow the post
> increment addressing mode to be used for the "dest" operand of CMP instructions
> used in these patterns.
> 
> This is currently causing trunk to FTB for msp430-elf since these instructions
> are being generated using an autoinc for the dest operand, and the assembler is
> rejecting them:
> 
>> ldtoa.s:1104: Error: this addressing mode is not applicable for destination operand
> 
> The attached patch fixes this by using the "msp430_general_dst_nonv_operand"
> predicate instead of the "nonimmediate_operand" predicate for the offending RTL
> patterns.
> 
> Successfully regtested for msp430-elf on trunk and committed as obvious.
> 
Thanks.  I suspect that'll bring the msp430 back to "green" state in my
tester.  I'd been meaning to bisect that, but I'm fighting multiple
other higher priority issues right now.

jeff