On Wed, Aug 13, 2014 at 7:14 PM, Bill Schmidt <wschm...@linux.vnet.ibm.com> wrote: > Hi, > > This patch adds a PowerPC-specific pass just prior to the first cse RTL > pass. The pass runs only when generating little-endian code for Power8 > with VSX enabled, and for -O1 and up. For this particular subtarget, > the use of the big-endian-biased vector load and store instructions > requires permutations to order vector elements for little endian. To > reduce the overhead of these permutations, this pass looks for > computations for which the exact lanes in which computations are > performed does not matter, so long as the results are returned to > storage in the proper order. For such computations we can remove the > xxpermdi's associated with the vector loads and stores. > > This patch relies on another patch posted today that converts a struct > used by the web pass into a base class that this patch can subclass. If > it's determined that the other patch isn't appropriate, then this patch > will need modifications to duplicate the union-find logic. > > A complete description of the new pass appears in rs6000.c (search for > "Analyze vector computations"). That description also identifies some > remaining opportunities we can follow up with later. > > A number of new tests are added to verify that the pass works as > expected for some vectorized code samples. > > Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no > regressions. Is this ok for trunk? > > Thanks, > Bill > > > [gcc] > > 2014-08-13 Bill Schmidt <wschm...@linux.vnet.ibm.com> > > * config/rs6000/rs6000.c (context.h): New include. > (tree-pass.h): Likewise. > (make_pass_analyze_swaps): New decl. > (rs6000_option_override): Register pass_analyze_swaps. > (swap_web_entry): New subsclass of web_entry_base (df.h). > (special_handling_values): New enum. > (union_defs): New function. > (union_uses): Likewise. > (insn_is_load_p): Likewise. > (insn_is_store_p): Likewise. > (insn_is_swap_p): Likewise. > (rtx_is_swappable_p): Likewise. > (insn_is_swappable_p): Likewise. > (chain_purpose): New enum. > (chain_contains_only_swaps): New function. > (mark_swaps_for_removal): Likewise. > (swap_const_vector_halves): Likewise. > (adjust_subreg_index): Likewise. > (permute_load): Likewise. > (permute_store): Likewise. > (handle_special_swappables): Likewise. > (replace_swap_with_copy): Likewise. > (dump_swap_insn_table): Likewise. > (rs6000_analyze_swaps): Likewise. > (pass_data_analyze_swaps): New pass_data. > (pass_analyze_swaps): New rtl_opt_pass. > (make_pass_analyze_swaps): New function. > * config/rs6000/rs6000.opt (moptimize-swaps): New option. > > [gcc/testsuite] > > 2014-08-13 Bill Schmidt <wschm...@linux.vnet.ibm.com> > > * gcc.target/powerpc/swaps-p8-1.c: New test. > * gcc.target/powerpc/swaps-p8-2.c: New test. > * gcc.target/powerpc/swaps-p8-3.c: New test. > * gcc.target/powerpc/swaps-p8-4.c: New test. > * gcc.target/powerpc/swaps-p8-5.c: New test. > * gcc.target/powerpc/swaps-p8-6.c: New test. > * gcc.target/powerpc/swaps-p8-7.c: New test. > * gcc.target/powerpc/swaps-p8-8.c: New test. > * gcc.target/powerpc/swaps-p8-9.c: New test. > * gcc.target/powerpc/swaps-p8-10.c: New test. > * gcc.target/powerpc/swaps-p8-11.c: New test. > * gcc.target/powerpc/swaps-p8-12.c: New test.
This looks okay, although I was hoping that other developers with more DF and web experience would double check. Why are you specifically gating the pass on POWER8? Thanks, David
