Hi!
On Wed, Feb 26, 2020 at 01:02:46PM +0100, Henri Cloetens wrote:
> 1. The epilogue generator emits an instruction "popret_internal" that
> a. Restores R18 in mode DI. (which corresponds to R18 and R19 in
> mode SI)
> b. Does the function return.
> 2. Then, during scheduling, the compiler shifts an add instruction PAST
> this return
> instruction, which is incorrect, because:
> (a.) The instruction writes R19. (it restores R18 and R19). The
> scheduler should see this.
Yes. So why doesn't it? Look at the various dump files to see what the
df ("dataflow") framework thinks about this.
> (b.) The instruction changes the PC (program counter).
The documentation says you should write just
(return)
instead of
(set (pc) (return))
(unlikely to be causing any of this, but a good cleanup to make).
> Q. Why is this happening ?. How can I prevent this ?.
You can have the scheduler print much more debugging info, but I'd
start with the usual stuff: -dap.
Segher
