On Mon, 27 Nov 2023, Tamar Christina wrote:
> Hi All,
>
> LIM notices that in some cases the condition and the results are loop
> invariant and tries to move them out of the loop.
>
> While the resulting code is operationally sound, moving the compare out of the
> gcond results in generating code that no longer branches, so cbranch is no
> longer applicable. As such I now add code to check during this motion to see
> if the target supports flag setting vector comparison as general operation.
>
> I have tried writing a GIMPLE testcase for this but the gimple FE seems to be
> having some trouble with the vector types. It seems to fail parsing.
>
> The early break code testsuite however has a test for this
> (vect-early-break_67.c).
>
> Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
>
> Ok for master?
OK.
Thanks,
Richard.
> Thanks,
> Tamar
>
> gcc/ChangeLog:
>
> * tree-ssa-loop-im.cc (determine_max_movement): Import insn-codes.h
> and optabs-tree.h and check for vector compare motion out of gcond.
>
> --- inline copy of patch --
> diff --git a/gcc/tree-ssa-loop-im.cc b/gcc/tree-ssa-loop-im.cc
> index
> 396963b6754c7671e2e5404302a69129918555e2..2ebf6d6548c4858fd5a8b4f9ab6f332f3fe8f6cd
> 100644
> --- a/gcc/tree-ssa-loop-im.cc
> +++ b/gcc/tree-ssa-loop-im.cc
> @@ -48,6 +48,8 @@ along with GCC; see the file COPYING3. If not see
> #include "tree-dfa.h"
> #include "tree-ssa.h"
> #include "dbgcnt.h"
> +#include "insn-codes.h"
> +#include "optabs-tree.h"
>
> /* TODO: Support for predicated code motion. I.e.
>
> @@ -852,6 +854,17 @@ determine_max_movement (gimple *stmt, bool
> must_preserve_exec)
> if (!extract_true_false_args_from_phi (dom, phi, NULL, NULL))
> return false;
>
> + /* Check if one of the depedent statement is a vector compare whether
> + the target supports it, otherwise it's invalid to hoist it out of
> + the gcond it belonged to. */
> + if (VECTOR_TYPE_P (TREE_TYPE (gimple_cond_lhs (cond))))
> + {
> + tree type = TREE_TYPE (gimple_cond_lhs (cond));
> + auto code = gimple_cond_code (cond);
> + if (!target_supports_op_p (type, code, optab_vector))
> + return false;
> + }
> +
> /* Fold in dependencies and cost of the condition. */
> FOR_EACH_SSA_TREE_OPERAND (val, cond, iter, SSA_OP_USE)
> {
>
>
>
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
