[PATCH 3/3] MSP430: Simplify and extend shift instruction patterns

Jeff Law law@redhat.com
Tue Aug 25 19:16:13 GMT 2020

On Tue, 2020-07-21 at 19:29 +0100, Jozef Lawrynowicz wrote:
> The implementation of define_expand and define_insn patterns to handle
> shifts in the MSP430 backend is inconsistent, resulting in missed
> opportunities to make best use of the architecture's features.
> There's now a single define_expand used as the entry point for all valid
> shifts, and the decision to either use a helper function to perform the
> shift (often required for the 430 ISA), or fall through to the
> define_insn patterns can be made from that expander function.
> Shifts by a constant amount have been grouped into one define_insn for
> each type of shift, instead of having different define_insn patterns for
> shifts by different amounts.
> A new target option "-mmax-inline-shift=" has been added to allow tuning
> of the number of shift instructions to emit inline, instead of using
> a library helper function.
> Successfully regtested on trunk for msp430-elf, ok to apply?

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