Problem with Delayed Branch Scheduling

[Ian Lance Taylor]

Steven Bosscher <stevenb@suse.de> writes:

> So you have a few instructions bundled into a VLIW instruction, and
> one of the instructions in the bundle is moved into the delay slot,
> thus breaking your VLIW bundle.  Right?

I think there are two natural approaches.

1) Do the VLIW bundling after delayed branch scheduling.  The way to
   do that is to the bundling in TARGET_ASM_FUNCTION_PROLOGUE.  The
   FRV backend does this.  I've done this successfully in the past.

2) When you do the VLIW bundling, put the instructions into a
   PARALLEL.

In general the gcc scheduler does not handle VLIW scheduling very
well, and it needs a fair amount of target specific help.

Ian