Re: [PATCH,rs6000] Optimize pcrel access of globals [ping]
Hi!
On Wed, Dec 09, 2020 at 11:04:44AM -0600, acsaw...@linux.ibm.com wrote:
> This patch implements a RTL pass that looks for pc-relative loads of the
> address of an external variable using the PCREL_GOT relocation and a
> single load or store that uses that external address.
> --- a/gcc/config.gcc
> +++ b/gcc/config.gcc
> @@ -509,7 +509,7 @@ or1k*-*-*)
> ;;
> powerpc*-*-*)
> cpu_type=rs6000
> - extra_objs="rs6000-string.o rs6000-p8swap.o rs6000-logue.o
> rs6000-call.o"
> + extra_objs="rs6000-string.o rs6000-p8swap.o rs6000-logue.o
> rs6000-call.o pcrel-opt.o"
Make this fit on its line? Just like extra_headers for example:
> extra_headers="ppc-asm.h altivec.h htmintrin.h htmxlintrin.h"
> extra_headers="${extra_headers} bmi2intrin.h bmiintrin.h"
> extra_headers="${extra_headers} xmmintrin.h mm_malloc.h emmintrin.h"
> +/* This file implements a RTL pass that looks for pc-relative loads of the
> + address of an external variable using the PCREL_GOT relocation and a
> single
> + load that uses that external address. If that is found we create the
> + PCREL_OPT relocation to possibly convert:
> +
> + pld addr_reg,var@pcrel@got
> +
> +
> +
> + lwz data_reg,0(addr_reg)
> +
> + into:
> +
> + plwz data_reg,var@pcrel
> +
> +
> +
> + nop
The nop first seems much simpler, but you cannot replace a 4-byte insn
with an 8-byte one (without huge effort). Pity. Maybe mention that
somewhere?
> + If the variable is not defined in the main program or the code using it is
> + not in the main program, the linker puts the address in the .got section
> and
> + generates:
> +
> + .section .got
> + .Lvar_got:
> + .dword var
> +
> + .section .text
> + pld addr_reg,.Lvar_got@pcrel
> +
> +
> +
> + lwz data_reg,0(addr_reg)
What is the advantage of this, over what we started with?
> + We look for a single usage in the basic block where the external
> + address is loaded. Multiple uses or references in another basic block
> will
> + force us to not use the PCREL_OPT relocation.
> +
> + We also optimize stores to the address of an external variable using the
> + PCREL_GOT relocation and a single store that uses that external address.
> If
> + that is found we create the PCREL_OPT relocation to possibly convert:
> +
> + pld addr_reg,var@pcrel@got
> +
> +
> +
> + stw data_reg,0(addr_reg)
> +
> + into:
> +
> + pstw data_reg,var@pcrel
> +
> +
> +
> + nop
> +
> + If the variable is not defined in the main program or the code using it is
> + not in the main program, the linker put the address in the .got section
> and
> + do:
"puts and does"? Or "will put and will do"?
> + .section .got
> + .Lvar_got:
> + .dword var
> +
> + .section .text
> + pld addr_reg,.Lvar_got@pcrel
> +
> +
> +
> + stw data_reg,0(addr_reg)
> +
> + We only look for a single usage in the basic block where the external
> + address is loaded. Multiple uses or references in another basic block
> will
> + force us to not use the PCREL_OPT relocation. */
That sounds like it is a restriction, but you cannot do better at all,
not without communicating a lot more info to the linker anyway.
> +#include "config.h"
> +#include "system.h"
> +#include "coretypes.h"
> +#include "backend.h"
> +#include "rtl.h"
> +#include "tree.h"
> +#include "memmodel.h"
> +#include "expmed.h"
> +#include "optabs.h"
> +#include "recog.h"
> +#include "df.h"
> +#include "tm_p.h"
> +#include "ira.h"
> +#include "print-tree.h"
> +#include "varasm.h"
> +#include "explow.h"
> +#include "expr.h"
> +#include "output.h"
> +#include "tree-pass.h"
> +#include "rtx-vector-builder.h"
> +#include "print-rtl.h"
> +#include "insn-attr.h"
> +#include "insn-codes.h"
Do you need all these header files? It looks quite reduced, and in the
right order, but did you check :-)
> +/* Various counters. */
> +static struct {
> + unsigned long extern_addrs;
> + unsigned long loads;
> + unsigned long adjacent_loads;
> + unsigned long failed_loads;
> + unsigned long stores;
> + unsigned long adjacent_stores;
> + unsigned long failed_stores;
> +} counters;
There is the whole statistics.[ch] you could use for this. I've never
used it, no idea if there are actual advantages to it :-)
> +/* Return a marker to identify the PCREL_OPT load address and
> + load/store instruction. We use a unique integer which is appended
> + to ".Lpcrel" to make the label. */
> +
> +static rtx
> +pcrel_opt_next_marker (void)
> +{
> + static unsigned int pcrel_opt_next_num;
> +
> + pcrel_opt_next_num++;
> + return GEN_INT (pcrel_opt_next_num);
> +}
You could just open-code it the whole two places you use this, that is
more straightforward.
> +/* Optimize a PC-relative load address to be used in a load.
> +
> + If the
Re: [PATCH,rs6000] Optimize pcrel access of globals [ping]
Ping. Aaron Sawdey, Ph.D. saw...@linux.ibm.com IBM Linux on POWER Toolchain > On Dec 9, 2020, at 11:04 AM, acsaw...@linux.ibm.com wrote: > > From: Aaron Sawdey > > Ping. I've folded in the changes to comments suggested by Will Schmidt. > > This patch implements a RTL pass that looks for pc-relative loads of the > address of an external variable using the PCREL_GOT relocation and a > single load or store that uses that external address. > > Produced by a cast of thousands: > * Michael Meissner > * Peter Bergner > * Bill Schmidt > * Alan Modra > * Segher Boessenkool > * Aaron Sawdey > > Passes bootstrap/regtest on ppc64le power10. Should have no effect on > other processors. OK for trunk? > > Thanks! > Aaron > > gcc/ChangeLog: > > * config.gcc: Add pcrel-opt.c and pcrel-opt.o. > * config/rs6000/pcrel-opt.c: New file. > * config/rs6000/pcrel-opt.md: New file. > * config/rs6000/predicates.md: Add d_form_memory predicate. > * config/rs6000/rs6000-cpus.def: Add OPTION_MASK_PCREL_OPT. > * config/rs6000/rs6000-passes.def: Add pass_pcrel_opt. > * config/rs6000/rs6000-protos.h: Add reg_to_non_prefixed(), > offsettable_non_prefixed_memory(), output_pcrel_opt_reloc(), > and make_pass_pcrel_opt(). > * config/rs6000/rs6000.c (reg_to_non_prefixed): Make global. > (rs6000_option_override_internal): Add pcrel-opt. > (rs6000_delegitimize_address): Support pcrel-opt. > (rs6000_opt_masks): Add pcrel-opt. > (offsettable_non_prefixed_memory): New function. > (reg_to_non_prefixed): Make global. > (rs6000_asm_output_opcode): Reset next_insn_prefixed_p. > (output_pcrel_opt_reloc): New function. > * config/rs6000/rs6000.md (loads_extern_addr): New attr. > (pcrel_extern_addr): Set loads_extern_addr. > Add include for pcrel-opt.md. > * config/rs6000/rs6000.opt: Add -mpcrel-opt. > * config/rs6000/t-rs6000: Add rules for pcrel-opt.c and > pcrel-opt.md. > > gcc/testsuite/ChangeLog: > > * gcc.target/powerpc/pcrel-opt-inc-di.c: New test. > * gcc.target/powerpc/pcrel-opt-ld-df.c: New test. > * gcc.target/powerpc/pcrel-opt-ld-di.c: New test. > * gcc.target/powerpc/pcrel-opt-ld-hi.c: New test. > * gcc.target/powerpc/pcrel-opt-ld-qi.c: New test. > * gcc.target/powerpc/pcrel-opt-ld-sf.c: New test. > * gcc.target/powerpc/pcrel-opt-ld-si.c: New test. > * gcc.target/powerpc/pcrel-opt-ld-vector.c: New test. > * gcc.target/powerpc/pcrel-opt-st-df.c: New test. > * gcc.target/powerpc/pcrel-opt-st-di.c: New test. > * gcc.target/powerpc/pcrel-opt-st-hi.c: New test. > * gcc.target/powerpc/pcrel-opt-st-qi.c: New test. > * gcc.target/powerpc/pcrel-opt-st-sf.c: New test. > * gcc.target/powerpc/pcrel-opt-st-si.c: New test. > * gcc.target/powerpc/pcrel-opt-st-vector.c: New test. > --- > gcc/config.gcc| 6 +- > gcc/config/rs6000/pcrel-opt.c | 888 ++ > gcc/config/rs6000/pcrel-opt.md| 386 > gcc/config/rs6000/predicates.md | 23 + > gcc/config/rs6000/rs6000-cpus.def | 2 + > gcc/config/rs6000/rs6000-passes.def | 8 + > gcc/config/rs6000/rs6000-protos.h | 4 + > gcc/config/rs6000/rs6000.c| 116 ++- > gcc/config/rs6000/rs6000.md | 8 +- > gcc/config/rs6000/rs6000.opt | 4 + > gcc/config/rs6000/t-rs6000| 7 +- > .../gcc.target/powerpc/pcrel-opt-inc-di.c | 18 + > .../gcc.target/powerpc/pcrel-opt-ld-df.c | 36 + > .../gcc.target/powerpc/pcrel-opt-ld-di.c | 43 + > .../gcc.target/powerpc/pcrel-opt-ld-hi.c | 42 + > .../gcc.target/powerpc/pcrel-opt-ld-qi.c | 42 + > .../gcc.target/powerpc/pcrel-opt-ld-sf.c | 42 + > .../gcc.target/powerpc/pcrel-opt-ld-si.c | 41 + > .../gcc.target/powerpc/pcrel-opt-ld-vector.c | 36 + > .../gcc.target/powerpc/pcrel-opt-st-df.c | 36 + > .../gcc.target/powerpc/pcrel-opt-st-di.c | 37 + > .../gcc.target/powerpc/pcrel-opt-st-hi.c | 42 + > .../gcc.target/powerpc/pcrel-opt-st-qi.c | 42 + > .../gcc.target/powerpc/pcrel-opt-st-sf.c | 36 + > .../gcc.target/powerpc/pcrel-opt-st-si.c | 41 + > .../gcc.target/powerpc/pcrel-opt-st-vector.c | 36 + > 26 files changed, 2013 insertions(+), 9 deletions(-) > create mode 100644 gcc/config/rs6000/pcrel-opt.c > create mode 100644 gcc/config/rs6000/pcrel-opt.md > create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-inc-di.c > create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-df.c > create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-di.c > create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-hi.c > create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-qi.c > create mode 100644
[PATCH,rs6000] Optimize pcrel access of globals [ping]
From: Aaron Sawdey Ping. I've folded in the changes to comments suggested by Will Schmidt. This patch implements a RTL pass that looks for pc-relative loads of the address of an external variable using the PCREL_GOT relocation and a single load or store that uses that external address. Produced by a cast of thousands: * Michael Meissner * Peter Bergner * Bill Schmidt * Alan Modra * Segher Boessenkool * Aaron Sawdey Passes bootstrap/regtest on ppc64le power10. Should have no effect on other processors. OK for trunk? Thanks! Aaron gcc/ChangeLog: * config.gcc: Add pcrel-opt.c and pcrel-opt.o. * config/rs6000/pcrel-opt.c: New file. * config/rs6000/pcrel-opt.md: New file. * config/rs6000/predicates.md: Add d_form_memory predicate. * config/rs6000/rs6000-cpus.def: Add OPTION_MASK_PCREL_OPT. * config/rs6000/rs6000-passes.def: Add pass_pcrel_opt. * config/rs6000/rs6000-protos.h: Add reg_to_non_prefixed(), offsettable_non_prefixed_memory(), output_pcrel_opt_reloc(), and make_pass_pcrel_opt(). * config/rs6000/rs6000.c (reg_to_non_prefixed): Make global. (rs6000_option_override_internal): Add pcrel-opt. (rs6000_delegitimize_address): Support pcrel-opt. (rs6000_opt_masks): Add pcrel-opt. (offsettable_non_prefixed_memory): New function. (reg_to_non_prefixed): Make global. (rs6000_asm_output_opcode): Reset next_insn_prefixed_p. (output_pcrel_opt_reloc): New function. * config/rs6000/rs6000.md (loads_extern_addr): New attr. (pcrel_extern_addr): Set loads_extern_addr. Add include for pcrel-opt.md. * config/rs6000/rs6000.opt: Add -mpcrel-opt. * config/rs6000/t-rs6000: Add rules for pcrel-opt.c and pcrel-opt.md. gcc/testsuite/ChangeLog: * gcc.target/powerpc/pcrel-opt-inc-di.c: New test. * gcc.target/powerpc/pcrel-opt-ld-df.c: New test. * gcc.target/powerpc/pcrel-opt-ld-di.c: New test. * gcc.target/powerpc/pcrel-opt-ld-hi.c: New test. * gcc.target/powerpc/pcrel-opt-ld-qi.c: New test. * gcc.target/powerpc/pcrel-opt-ld-sf.c: New test. * gcc.target/powerpc/pcrel-opt-ld-si.c: New test. * gcc.target/powerpc/pcrel-opt-ld-vector.c: New test. * gcc.target/powerpc/pcrel-opt-st-df.c: New test. * gcc.target/powerpc/pcrel-opt-st-di.c: New test. * gcc.target/powerpc/pcrel-opt-st-hi.c: New test. * gcc.target/powerpc/pcrel-opt-st-qi.c: New test. * gcc.target/powerpc/pcrel-opt-st-sf.c: New test. * gcc.target/powerpc/pcrel-opt-st-si.c: New test. * gcc.target/powerpc/pcrel-opt-st-vector.c: New test. --- gcc/config.gcc| 6 +- gcc/config/rs6000/pcrel-opt.c | 888 ++ gcc/config/rs6000/pcrel-opt.md| 386 gcc/config/rs6000/predicates.md | 23 + gcc/config/rs6000/rs6000-cpus.def | 2 + gcc/config/rs6000/rs6000-passes.def | 8 + gcc/config/rs6000/rs6000-protos.h | 4 + gcc/config/rs6000/rs6000.c| 116 ++- gcc/config/rs6000/rs6000.md | 8 +- gcc/config/rs6000/rs6000.opt | 4 + gcc/config/rs6000/t-rs6000| 7 +- .../gcc.target/powerpc/pcrel-opt-inc-di.c | 18 + .../gcc.target/powerpc/pcrel-opt-ld-df.c | 36 + .../gcc.target/powerpc/pcrel-opt-ld-di.c | 43 + .../gcc.target/powerpc/pcrel-opt-ld-hi.c | 42 + .../gcc.target/powerpc/pcrel-opt-ld-qi.c | 42 + .../gcc.target/powerpc/pcrel-opt-ld-sf.c | 42 + .../gcc.target/powerpc/pcrel-opt-ld-si.c | 41 + .../gcc.target/powerpc/pcrel-opt-ld-vector.c | 36 + .../gcc.target/powerpc/pcrel-opt-st-df.c | 36 + .../gcc.target/powerpc/pcrel-opt-st-di.c | 37 + .../gcc.target/powerpc/pcrel-opt-st-hi.c | 42 + .../gcc.target/powerpc/pcrel-opt-st-qi.c | 42 + .../gcc.target/powerpc/pcrel-opt-st-sf.c | 36 + .../gcc.target/powerpc/pcrel-opt-st-si.c | 41 + .../gcc.target/powerpc/pcrel-opt-st-vector.c | 36 + 26 files changed, 2013 insertions(+), 9 deletions(-) create mode 100644 gcc/config/rs6000/pcrel-opt.c create mode 100644 gcc/config/rs6000/pcrel-opt.md create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-inc-di.c create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-df.c create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-di.c create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-hi.c create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-qi.c create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-sf.c create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-si.c create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-vector.c create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-df.c create
