[RISC-V][V2] Fix type on vector move patterns

Updated version of my prior patch to fix type attributes on the
pre-allocation vector move pattern.  This version just adds a suitable
set of attributes to a second pattern that was obviously wrong.

Passed on my tester for rv64 and rv32 crosses.  Bootstrapped and
regression tested on riscv64-linux-gnu as well.

--

So I was looking into a horrific schedule for SAD a week or so ago and
came across this gem.

Basically we were treating a vector load as a vector move from a
scheduling standpoint during sched1.  Naturally we didn't expose much
ILP during sched1.  That in turn caused the register allocator to pack
the pseudos onto the physical vector registers tightly.  regrename
didn't do anything useful and the resulting code had too many false
dependencies for sched2 to do anything useful.

As a result we were taking many load->use stalls in x264's SAD routine.

I'm confident the types are fine, but I'm a lot less sure about the
other attributes (mode, avl_type_index, mode_idx).  If someone could
take a look at that, it'd be greatly appreciated.

There's other cases that may need similar treatment.  But I didn't want
to muck with them until I understood those other attributes and how they
need adjustments.

In particular mov<VLS_AVL_REG:mode><P:mode>_lra appears to have the same
problem.

--

gcc/
	* config/riscv/vector.md (mov<mode> pattern/splitter): Fix type and
	other attributes.
	(mov<VLS_AVL_REG:mode><P:mode>_lra): Likewise.
This commit is contained in:
Jeff Law 2024-11-14 16:57:50 -07:00
parent f70c1d517e
commit aaada43a2a

View file

@ -1395,7 +1395,10 @@
gcc_assert (ok_p);
DONE;
}
[(set_attr "type" "vmov")]
[(set_attr "type" "vlde,vste,vmov")
(set_attr "mode" "<MODE>")
(set (attr "avl_type_idx") (const_int INVALID_ATTRIBUTE))
(set (attr "mode_idx") (const_int INVALID_ATTRIBUTE))]
)
(define_expand "mov<mode>"
@ -1442,7 +1445,10 @@
}
DONE;
}
[(set_attr "type" "vmov")]
[(set_attr "type" "vlde,vste,vmov")
(set_attr "mode" "<VLS_AVL_REG:MODE>")
(set (attr "avl_type_idx") (const_int INVALID_ATTRIBUTE))
(set (attr "mode_idx") (const_int INVALID_ATTRIBUTE))]
)
(define_insn "*mov<mode>_vls"