[PATCH,rs6000] Optimize pcrel access of globals [ping]

Aaron Sawdey acsawdey@linux.ibm.com
Tue Jan 19 04:45:58 GMT 2021


Ping.

Aaron Sawdey, Ph.D. sawdey@linux.ibm.com
IBM Linux on POWER Toolchain
 

> On Dec 9, 2020, at 11:04 AM, acsawdey@linux.ibm.com wrote:
> 
> From: Aaron Sawdey <acsawdey@linux.ibm.com>
> 
> 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 mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-di.c
> create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-hi.c
> create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-qi.c
> create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-sf.c
> create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-si.c
> create mode 100644 gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-vector.c
> 
> diff --git a/gcc/config.gcc b/gcc/config.gcc
> index dc6d68bd4eb..1e4862785ea 100644
> --- 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"
> 	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"
> @@ -524,6 +524,7 @@ powerpc*-*-*)
> 	esac
> 	extra_options="${extra_options} g.opt fused-madd.opt rs6000/rs6000-tables.opt"
> 	target_gtfiles="$target_gtfiles \$(srcdir)/config/rs6000/rs6000-logue.c \$(srcdir)/config/rs6000/rs6000-call.c"
> +	target_gtfiles="$target_gtfiles \$(srcdir)/config/rs6000/pcrel-opt.c"
> 	;;
> pru-*-*)
> 	cpu_type=pru
> @@ -535,8 +536,9 @@ riscv*)
> 	;;
> rs6000*-*-*)
> 	extra_options="${extra_options} g.opt fused-madd.opt rs6000/rs6000-tables.opt"
> -	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"
> 	target_gtfiles="$target_gtfiles \$(srcdir)/config/rs6000/rs6000-logue.c \$(srcdir)/config/rs6000/rs6000-call.c"
> +	target_gtfiles="$target_gtfiles \$(srcdir)/config/rs6000/pcrel-opt.c"
> 	;;
> sparc*-*-*)
> 	cpu_type=sparc
> diff --git a/gcc/config/rs6000/pcrel-opt.c b/gcc/config/rs6000/pcrel-opt.c
> new file mode 100644
> index 00000000000..c49358ddf51
> --- /dev/null
> +++ b/gcc/config/rs6000/pcrel-opt.c
> @@ -0,0 +1,888 @@
> +/* Subroutines used support the pc-relative linker optimization.
> +   Copyright (C) 2020 Free Software Foundation, Inc.
> +
> +   This file is part of GCC.
> +
> +   GCC is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published
> +   by the Free Software Foundation; either version 3, or (at your
> +   option) any later version.
> +
> +   GCC is distributed in the hope that it will be useful, but WITHOUT
> +   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
> +   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
> +   License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with GCC; see the file COPYING3.  If not see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +/* 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
> +
> +	<possibly other insns that do not use 'addr_reg' or 'data_reg'>
> +
> +	lwz data_reg,0(addr_reg)
> +
> +   into:
> +
> +	plwz data_reg,var@pcrel
> +
> +	<possibly other insns that do not use 'addr_reg' or 'data_reg'>
> +
> +	nop
> +
> +   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
> +
> +		<possibly other insns that do not use 'addr_reg' or 'data_reg'>
> +
> +		lwz data_reg,0(addr_reg)
> +
> +   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
> +
> +	<possibly other insns that do not use 'addr_reg' or 'data_reg'>
> +
> +	stw data_reg,0(addr_reg)
> +
> +   into:
> +
> +	pstw data_reg,var@pcrel
> +
> +	<possibly other insns that do not use 'addr_reg' or 'data_reg'>
> +
> +	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:
> +
> +		.section .got
> +	.Lvar_got:
> +		.dword var
> +
> +		.section .text
> +		pld addr_reg,.Lvar_got@pcrel
> +
> +		<possibly other insns that do not use 'addr_reg' or 'data_reg'>
> +
> +		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.  */
> +
> +#define IN_TARGET_CODE 1
> +
> +#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"
> +
> +/* 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;
> +
> +/* 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);
> +}
> +
> +/* Optimize a PC-relative load address to be used in a load.
> +
> +   If the sequence of insns is safe to use the PCREL_OPT optimization (i.e. no
> +   additional references to the address register, the address register dies at
> +   the load, and no references to the load), convert insns of the form:
> +
> +	(set (reg:DI addr)
> +	     (symbol_ref:DI "ext_symbol"))
> +
> +	...
> +
> +	(set (reg:<MODE> value)
> +	     (mem:<MODE> (reg:DI addr)))
> +
> +   into:
> +
> +	(parallel [(set (reg:DI addr)
> +			(unspec:<MODE> [(symbol_ref:DI "ext_symbol")
> +					(const_int label_num)
> +					(const_int 0)]
> +				       UNSPEC_PCREL_OPT_LD_ADDR))
> +		   (set (reg:DI data)
> +			(unspec:DI [(const_int 0)]
> +				   UNSPEC_PCREL_OPT_LD_ADDR))])
> +
> +	...
> +
> +	(parallel [(set (reg:<MODE>)
> +			(unspec:<MODE> [(mem:<MODE> (reg:DI addr))
> +					(reg:DI data)
> +					(const_int label_num)]
> +				       UNSPEC_PCREL_OPT_LD_RELOC))
> +		   (clobber (reg:DI addr))])
> +
> +   If the register being loaded is the same register that was used to hold the
> +   external address, we generate the following insn instead:
> +
> +	(set (reg:DI data)
> +	     (unspec:DI [(symbol_ref:DI "ext_symbol")
> +			 (const_int label_num)
> +			 (const_int 1)]
> +			UNSPEC_PCREL_OPT_LD_ADDR))
> +
> +   In the first insn, we set both the address of the external variable, and
> +   mark that the variable being loaded both are created in that insn, and are
> +   consumed in the second insn.  It doesn't matter what mode the register that
> +   we will ultimately do the load into, so we use DImode.  We just need to mark
> +   that both registers may be set in the first insn, and will be used in the
> +   second insn.
> +
> +   The UNSPEC_PCREL_OPT_LD_ADDR insn will generate the load address plus
> +   a definition of a label (.Lpcrel<n>), while the UNSPEC_PCREL_OPT_LD_RELOC
> +   insn will generate the .reloc to tell the linker to tie the load address and
> +   load using that address together.
> +
> +	pld b,ext_symbol@got@pcrel
> +   .Lpcrel1:
> +
> +	...
> +
> +	.reloc .Lpcrel1-8,R_PPC64_PCREL_OPT,.-(.Lpcrel1-8)
> +	lwz r,0(b)
> +
> +   If ext_symbol is defined in another object file in the main program and we
> +   are linking the main program, the linker will convert the above instructions
> +   to:
> +
> +	plwz r,ext_symbol@got@pcrel
> +
> +	...
> +
> +	nop  */
> +
> +static void
> +pcrel_opt_load (rtx_insn *addr_insn,		/* insn loading address.  */
> +		rtx_insn *load_insn)		/* insn using address.  */
> +{
> +  rtx addr_set = PATTERN (addr_insn);
> +  gcc_assert (GET_CODE (addr_set) == SET);
> +
> +  rtx addr_reg = SET_DEST (addr_set);
> +  gcc_assert (base_reg_operand (addr_reg, Pmode));
> +
> +  rtx addr_symbol = SET_SRC (addr_set);
> +  gcc_assert (pcrel_external_address (addr_symbol, Pmode));
> +
> +  rtx load_set = PATTERN (load_insn);
> +  gcc_assert (GET_CODE (load_set) == SET);
> +
> +  /* Make sure there are no references to the register being loaded
> +     between the two insns.  */
> +  rtx reg = SET_DEST (load_set);
> +  if (!register_operand (reg, GET_MODE (reg))
> +      || reg_used_between_p (reg, addr_insn, load_insn)
> +      || reg_set_between_p (reg, addr_insn, load_insn))
> +    return;
> +
> +  rtx mem = SET_SRC (load_set);
> +  machine_mode reg_mode = GET_MODE (reg);
> +  machine_mode mem_mode = GET_MODE (mem);
> +  rtx mem_inner = mem;
> +  unsigned int reg_regno = reg_or_subregno (reg);
> +
> +  /* LWA is a DS format instruction, but LWZ is a D format instruction.  We use
> +     DImode for the mode to force checking whether the bottom 2 bits are 0.
> +     However FPR and vector registers uses the LFIWAX/LXSIWAX instructions
> +     which only have indexed forms.  */
> +  if (GET_CODE (mem) == SIGN_EXTEND && GET_MODE (XEXP (mem, 0)) == SImode)
> +    {
> +      if (!INT_REGNO_P (reg_regno))
> +	return;
> +
> +      mem_inner = XEXP (mem, 0);
> +      mem_mode = DImode;
> +    }
> +
> +  else if (GET_CODE (mem) == SIGN_EXTEND
> +	   || GET_CODE (mem) == ZERO_EXTEND
> +	   || GET_CODE (mem) == FLOAT_EXTEND)
> +    {
> +      mem_inner = XEXP (mem, 0);
> +      mem_mode = GET_MODE (mem_inner);
> +    }
> +
> +  if (!MEM_P (mem_inner))
> +    return;
> +
> +  /* If the address isn't a non-prefixed offsettable instruction, we can't do
> +     the optimization.  */
> +  if (!offsettable_non_prefixed_memory (reg, mem_mode, mem_inner))
> +    return;
> +
> +  /* Allocate a new PC-relative label, and update the load external address
> +     insn.
> +
> +     If the register being loaded is different from the address register, we
> +     need to indicate both registers are set at the load of the address.
> +
> +	(parallel [(set (reg load)
> +			(unspec [(symbol_ref addr_symbol)
> +				 (const_int label_num)]
> +				UNSPEC_PCREL_OPT_LD_ADDR))
> +		   (set (reg addr)
> +			(unspec [(const_int 0)]
> +				UNSPEC_PCREL_OPT_LD_ADDR))])
> +
> +     If the register being loaded is the same as the address register, we use
> +     an alternate form:
> +
> +	(set (reg load)
> +	     (unspec [(symbol_ref addr_symbol)
> +		      (const_int label_num)]
> +		     UNSPEC_PCREL_OPT_LD_ADDR_SAME_REG))  */
> +  unsigned int addr_regno = reg_or_subregno (addr_reg);
> +  rtx label_num = pcrel_opt_next_marker ();
> +  rtx reg_di = gen_rtx_REG (DImode, reg_regno);
> +  rtx addr_pattern;
> +
> +  /* Create the load address, either using the pattern with an explicit clobber
> +     if the address register is not the same as the register being loaded, or
> +     using the pattern that requires the address register to be the address
> +     loaded.  */
> +  if (addr_regno != reg_regno)
> +    addr_pattern = gen_pcrel_opt_ld_addr (addr_reg, addr_symbol, label_num,
> +					  reg_di);
> +  else
> +    addr_pattern = gen_pcrel_opt_ld_addr_same_reg (addr_reg, addr_symbol,
> +						   label_num);
> +
> +  validate_change (addr_insn, &PATTERN (addr_insn), addr_pattern, false);
> +
> +  /* Update the load insn.  If the mem had a sign/zero/float extend, add that
> +     also after doing the UNSPEC.  Add an explicit clobber of the external
> +     address register just to make it clear that the address register dies.
> +
> +	(parallel [(set (reg:<MODE> data)
> +			(unspec:<MODE> [(mem (addr_reg)
> +					(reg:DI data)
> +					(const_int label_num)]
> +				       UNSPEC_PCREL_OPT_LD_RELOC))
> +		   (clobber (reg:DI addr_reg))])  */
> +  rtvec v_load = gen_rtvec (3, mem_inner, reg_di, label_num);
> +  rtx new_load = gen_rtx_UNSPEC (GET_MODE (mem_inner), v_load,
> +				 UNSPEC_PCREL_OPT_LD_RELOC);
> +
> +  if (GET_CODE (mem) != GET_CODE (mem_inner))
> +    new_load = gen_rtx_fmt_e (GET_CODE (mem), reg_mode, new_load);
> +
> +  rtx new_load_set = gen_rtx_SET (reg, new_load);
> +  rtx load_clobber = gen_rtx_CLOBBER (VOIDmode,
> +				      (addr_regno == reg_regno
> +				       ? gen_rtx_SCRATCH (Pmode)
> +				       : addr_reg));
> +  rtx new_load_pattern
> +    = gen_rtx_PARALLEL (VOIDmode, gen_rtvec (2, new_load_set, load_clobber));
> +
> +  validate_change (load_insn, &PATTERN (load_insn), new_load_pattern, false);
> +
> +  /* Note whether the changes were sucessful or not.  */
> +  if (apply_change_group ())
> +    {
> +      /* PCREL_OPT load optimization succeeded.  */
> +      counters.loads++;
> +      if (next_nonnote_insn (addr_insn) == load_insn)
> +	counters.adjacent_loads++;
> +
> +      if (dump_file)
> +	fprintf (dump_file,
> +		 "PCREL_OPT load (addr insn = %d, use insn = %d).\n",
> +		 INSN_UID (addr_insn),
> +		 INSN_UID (load_insn));
> +
> +      df_analyze ();
> +    }
> +  else
> +    {
> +      /* PCREL_OPT load optimization did not succeed.  */
> +      counters.failed_loads++;
> +      if (dump_file)
> +	fprintf (dump_file,
> +		 "PCREL_OPT load failed (addr insn = %d, use insn = %d).\n",
> +		 INSN_UID (addr_insn),
> +		 INSN_UID (load_insn));
> +    }
> +
> +  return;
> +}
> +
> +/* Optimize a PC-relative load address to be used in a store.
> +
> +   If the sequence of insns is safe to use the PCREL_OPT optimization (i.e. no
> +   additional references to the address register, the address register dies at
> +   the load, and no references to the load), convert insns of the form:
> +
> +	(set (reg:DI addr)
> +	     (symbol_ref:DI "ext_symbol"))
> +
> +	...
> +
> +	(set (mem:<MODE> (reg:DI addr))
> +	     (reg:<MODE> value))
> +
> +   into:
> +
> +	(parallel [(set (reg:DI addr)
> +			(unspec:DI [(symbol_ref:DI "ext_symbol")
> +				    (const_int label_num)]
> +				  UNSPEC_PCREL_OPT_ST_ADDR))
> +		  (use (reg:<MODE> value))])
> +
> +	...
> +
> +	(parallel [(set (mem:<MODE> (reg:DI addr))
> +			(unspec:<MODE> [(reg:<MODE>)
> +					(const_int label_num)]
> +				       UNSPEC_PCREL_OPT_ST_RELOC))
> +		   (clobber (reg:DI addr))])
> +
> +   The UNSPEC_PCREL_OPT_ST_ADDR insn will generate the load address plus a
> +   definition of a label (.Lpcrel<n>), while the UNSPEC_PCREL_OPT_ST_RELOC insn
> +   will generate the .reloc to tell the linker to tie the load address and load
> +   using that address together.
> +
> +	pld b,ext_symbol@got@pcrel
> +   .Lpcrel1:
> +
> +	...
> +
> +	.reloc .Lpcrel1-8,R_PPC64_PCREL_OPT,.-(.Lpcrel1-8)
> +	stw r,0(b)
> +
> +   If ext_symbol is defined in another object file in the main program and we
> +   are linking the main program, the linker will convert the above instructions
> +   to:
> +
> +	pstwz r,ext_symbol@got@pcrel
> +
> +	...
> +
> +	nop  */
> +
> +static void
> +pcrel_opt_store (rtx_insn *addr_insn,		/* insn loading address.  */
> +		 rtx_insn *store_insn)		/* insn using address.  */
> +{
> +  rtx addr_old_set = PATTERN (addr_insn);
> +  gcc_assert (GET_CODE (addr_old_set) == SET);
> +
> +  rtx addr_reg = SET_DEST (addr_old_set);
> +  gcc_assert (base_reg_operand (addr_reg, Pmode));
> +
> +  rtx addr_symbol = SET_SRC (addr_old_set);
> +  gcc_assert (pcrel_external_address (addr_symbol, Pmode));
> +
> +  rtx store_set = PATTERN (store_insn);
> +  gcc_assert (GET_CODE (store_set) == SET);
> +
> +  rtx mem = SET_DEST (store_set);
> +  if (!MEM_P (mem))
> +    return;
> +
> +  machine_mode mem_mode = GET_MODE (mem);
> +  rtx reg = SET_SRC (store_set);
> +
> +  /*  Don't allow storing the address of the external variable.  Make sure the
> +      value being stored wasn't updated.  */
> +  if (!register_operand (reg, GET_MODE (reg))
> +      && reg_or_subregno (reg) != reg_or_subregno (addr_reg)
> +      && !reg_set_between_p (reg, addr_insn, store_insn))
> +    return;
> +
> +  /* If the address isn't a non-prefixed offsettable instruction, we can't do
> +     the optimization.  */
> +  if (!offsettable_non_prefixed_memory (reg, mem_mode, mem))
> +    return;
> +
> +  /* Allocate a new PC-relative label, and update the load address insn.
> +
> +	(parallel [(set (reg addr)
> +			(unspec [(symbol_ref symbol)
> +				 (const_int label_num)]
> +				UNSPEC_PCREL_OPT_ST_ADDR))
> +		   (use (reg store))])  */
> +  rtx label_num = pcrel_opt_next_marker ();
> +  rtvec v_addr = gen_rtvec (2, addr_symbol, label_num);
> +  rtx addr_unspec = gen_rtx_UNSPEC (Pmode, v_addr,
> +				   UNSPEC_PCREL_OPT_ST_ADDR);
> +  rtx addr_new_set = gen_rtx_SET (addr_reg, addr_unspec);
> +  rtx addr_use = gen_rtx_USE (VOIDmode, reg);
> +  rtx addr_new_pattern
> +    = gen_rtx_PARALLEL (VOIDmode, gen_rtvec (2, addr_new_set, addr_use));
> +
> +  validate_change (addr_insn, &PATTERN (addr_insn), addr_new_pattern, false);
> +
> +  /* Update the store insn.  Add an explicit clobber of the external address
> +     register just to be sure there are no additional uses of the address
> +     register.
> +
> +	(parallel [(set (mem (addr_reg)
> +			(unspec:<MODE> [(reg)
> +					(const_int label_num)]
> +				       UNSPEC_PCREL_OPT_ST_RELOC))
> +		  (clobber (reg:DI addr_reg))])  */
> +  rtvec v_store = gen_rtvec (2, reg, label_num);
> +  rtx new_store = gen_rtx_UNSPEC (mem_mode, v_store,
> +				  UNSPEC_PCREL_OPT_ST_RELOC);
> +
> +  rtx new_store_set = gen_rtx_SET (mem, new_store);
> +  rtx store_clobber = gen_rtx_CLOBBER (VOIDmode, addr_reg);
> +  rtx new_store_pattern
> +    = gen_rtx_PARALLEL (VOIDmode, gen_rtvec (2, new_store_set, store_clobber));
> +
> +  validate_change (store_insn, &PATTERN (store_insn), new_store_pattern, false);
> +
> +  /* Note whether changes succeeded or not.  */
> +  if (apply_change_group ())
> +    {
> +      /* PCREL_OPT store succeeded.  */
> +      counters.stores++;
> +      if (next_nonnote_insn (addr_insn) == store_insn)
> +	counters.adjacent_stores++;
> +
> +      if (dump_file)
> +	fprintf (dump_file,
> +		 "PCREL_OPT store (addr insn = %d, use insn = %d).\n",
> +		 INSN_UID (addr_insn),
> +		 INSN_UID (store_insn));
> +
> +      df_analyze();
> +    }
> +  else
> +    {
> +      /* PCREL_OPT store failed.  */
> +      counters.failed_stores++;
> +      if (dump_file)
> +	fprintf (dump_file,
> +		 "PCREL_OPT store failed (addr insn = %d, use insn = %d).\n",
> +		 INSN_UID (addr_insn),
> +		 INSN_UID (store_insn));
> +    }
> +
> +  return;
> +}
> +
> +/* Return the register used as the base register of MEM.  We look for
> +   BSWAP and UNSPEC (which might be LFIWAX/LFIWZX/STFIWX) to exclude
> +   instructions that do not have a pc-relative form.  We don't
> +   explicitly look for lxvd2x (rotate or vec_select) because we do not
> +   expect to see that generated for p9 or newer anyway.  */
> +
> +static rtx
> +get_mem_base_reg (rtx mem)
> +{
> +  const char * fmt;
> +  /* If we have a zero_extend, etc., strip them.  */
> +  while (!MEM_P (mem))
> +    {
> +      if (GET_CODE (mem) == BSWAP
> +	  || GET_CODE (mem) == UNSPEC)
> +	return NULL_RTX;
> +      if (GET_RTX_LENGTH (GET_CODE (mem)) < 1)
> +	return NULL_RTX;
> +      fmt = GET_RTX_FORMAT (GET_CODE (mem));
> +      if (fmt[0] != 'e')
> +	return NULL_RTX;
> +      mem = XEXP (mem, 0);
> +      if (mem == NULL_RTX )
> +	return NULL_RTX;
> +    }
> +
> +  rtx addr_rtx;
> +  if (!MEM_SIZE_KNOWN_P (mem))
> +    return NULL_RTX;
> +
> +  addr_rtx = (XEXP (mem, 0));
> +  if (GET_CODE (addr_rtx) == PRE_MODIFY)
> +    addr_rtx = XEXP (addr_rtx, 1);
> +
> +  while (GET_CODE (addr_rtx) == PLUS
> +	 && CONST_INT_P (XEXP (addr_rtx, 1)))
> +    addr_rtx = XEXP (addr_rtx, 0);
> +
> +  return REG_P (addr_rtx) ? addr_rtx : NULL_RTX;
> +}
> +
> +/* Check whether INSN contains an invalid reference to REGNO.  If TYPE is a
> +   load or store instruction, then we cannot allow any definitions of REGNO.
> +   If TYPE is a load instruction, then we cannot allow any uses either.  */
> +
> +static bool
> +insn_references_regno_p (rtx_insn *insn, unsigned int regno, enum attr_type type)
> +{
> +  struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
> +  df_ref ref;
> +
> +  /* All definitions of REGNO are invalid.  */
> +  for (ref = DF_INSN_INFO_DEFS (insn_info); ref; ref = DF_REF_NEXT_LOC (ref))
> +    if (DF_REF_REGNO (ref) == regno)
> +      return true;
> +
> +  /* Any uses of REGNO are invalid if we're attempting to optimize a load.  */
> +  if (type == TYPE_LOAD
> +      || type == TYPE_FPLOAD
> +      || type == TYPE_VECLOAD)
> +    for (ref = DF_INSN_INFO_USES (insn_info); ref; ref = DF_REF_NEXT_LOC (ref))
> +      if (DF_REF_REGNO (ref) == regno)
> +	return true;
> +
> +  return false;
> +}
> +
> +/* Given an insn that loads up a base register with the address of an
> +   external symbol, see if we can optimize it with the PCREL_OPT
> +   optimization.  */
> +
> +static void
> +pcrel_opt_address (rtx_insn *addr_insn)
> +{
> +  counters.extern_addrs++;
> +
> +  /* Do some basic validation.  */
> +  rtx addr_set = PATTERN (addr_insn);
> +  if (GET_CODE (addr_set) != SET)
> +    return;
> +
> +  rtx addr_reg = SET_DEST (addr_set);
> +  rtx addr_symbol = SET_SRC (addr_set);
> +
> +  if (!base_reg_operand (addr_reg, Pmode)
> +      || !pcrel_external_address (addr_symbol, Pmode))
> +    return;
> +
> +  /* The address register must have exactly one definition.  */
> +  struct df_insn_info *insn_info = DF_INSN_INFO_GET (addr_insn);
> +  if (!insn_info)
> +    return;
> +
> +  df_ref def = df_single_def (insn_info);
> +  if (!def)
> +    return;
> +
> +  /* Make sure there is at least one use.  */
> +  df_link *chain = DF_REF_CHAIN (def);
> +  if (!chain || !chain->ref)
> +    return;
> +
> +  /* Get the insn of the possible load or store.  */
> +  rtx_insn *use_insn = DF_REF_INSN (chain->ref);
> +
> +  /* Ensure there are no other uses.  */
> +  for (chain = chain->next; chain; chain = chain->next)
> +    if (chain->ref && DF_REF_INSN_INFO (chain->ref))
> +      {
> +	gcc_assert (DF_REF_INSN (chain->ref));
> +	if (NONDEBUG_INSN_P (DF_REF_INSN (chain->ref)))
> +	  return;
> +      }
> +
> +  /* The use instruction must be a single non-prefixed instruction.  */
> +  if (get_attr_length (use_insn) != 4)
> +    return;
> +
> +  /* The address and the memory operation must be in the same basic block.  */
> +  if (BLOCK_FOR_INSN (use_insn) != BLOCK_FOR_INSN (addr_insn))
> +    return;
> +
> +  /* If this isn't a simple SET, skip doing the optimization.  */
> +  if (GET_CODE (PATTERN (use_insn)) != SET)
> +    return;
> +
> +  /* Check the insns between loading the address and its use to classify what
> +     type of insn it is.  */
> +  rtx_insn *insn;
> +  rtx_insn *last_insn_in_bb = BB_END (BLOCK_FOR_INSN (use_insn));
> +  enum attr_type use_insn_type = get_attr_type (use_insn);
> +  unsigned int use_regno;
> +
> +  switch (use_insn_type)
> +    {
> +    case TYPE_LOAD:
> +    case TYPE_FPLOAD:
> +    case TYPE_VECLOAD:
> +      /* Make sure our address register is the same register used in the
> +	 base address of the load.  */
> +      if (addr_reg != get_mem_base_reg (SET_SRC (PATTERN (use_insn))))
> +	return;
> +      use_regno = REGNO (SET_DEST (PATTERN (use_insn)));
> +      break;
> +    case TYPE_STORE:
> +    case TYPE_FPSTORE:
> +    case TYPE_VECSTORE:
> +      /* Make sure our address register is the same register used in the
> +	 base address of the store.  */
> +      if (addr_reg != get_mem_base_reg (SET_DEST (PATTERN (use_insn))))
> +	return;
> +      use_regno = REGNO (SET_SRC (PATTERN (use_insn)));
> +      break;
> +    default:
> +      /* We can only optimize loads and stores.  Ignore everything else.  */
> +      return;
> +    }
> +
> +
> +  for (insn = NEXT_INSN (addr_insn);
> +       insn != use_insn;
> +       insn = NEXT_INSN (insn))
> +    {
> +      /* If we see things like labels, calls, etc., or we've reached the end
> +	 of the block without seeing the load or store, then don't do the
> +	 PCREL_OPT optimization.  */
> +      if (!insn
> +	  || LABEL_P (insn)
> +	  || JUMP_P (insn)
> +	  || CALL_P (insn)
> +	  || BARRIER_P (insn)
> +	  || insn == last_insn_in_bb)
> +	return;
> +
> +      /* For a normal insn, see if it is a load or store.  */
> +      if (NONDEBUG_INSN_P (insn)
> +	  && GET_CODE (PATTERN (insn)) != USE
> +	  && GET_CODE (PATTERN (insn)) != CLOBBER)
> +	{
> +	  switch (get_attr_type (insn))
> +	    {
> +	    case TYPE_LOAD:
> +	      /* While load of the external address is a 'load' for scheduling
> +		 purposes, it should be safe to allow loading other external
> +		 addresses between the load of the external address we are
> +		 currently looking at and the load or store using that
> +		 address.  */
> +	      if (get_attr_loads_extern_addr (insn) == LOADS_EXTERN_ADDR_YES)
> +		break;
> +	      /* fall through */
> +
> +	    case TYPE_FPLOAD:
> +	    case TYPE_VECLOAD:
> +	      /* Don't do the PCREL_OPT store optimization if there is a load
> +		 operation.  For example, the load might be trying to load the
> +		 value being stored in between getting the address and doing
> +		 the store.  */
> +	      if (use_insn_type == TYPE_STORE
> +		  || use_insn_type == TYPE_FPSTORE
> +		  || use_insn_type == TYPE_VECSTORE)
> +		return;
> +	      break;
> +
> +	    case TYPE_STORE:
> +	    case TYPE_FPSTORE:
> +	    case TYPE_VECSTORE:
> +	      /* Don't do the PCREL_OPT load optimization if there is a store
> +		 operation.  Perhaps the store might be to the global variable
> +		 through a pointer.  */
> +	      return;
> +
> +	    case TYPE_LOAD_L:
> +	    case TYPE_STORE_C:
> +	    case TYPE_HTM:
> +	    case TYPE_HTMSIMPLE:
> +	      /* Don't do the optimization through atomic operations.  */
> +	      return;
> +
> +	    default:
> +	      break;
> +	    }
> +	}
> +
> +      /* Check for invalid references of the non-address register that is
> +	 used in the load or store instruction.  */
> +      if (insn_references_regno_p (insn, use_regno, use_insn_type))
> +	return;
> +    }
> +
> +  /* Is this a load or a store?  */
> +  switch (use_insn_type)
> +    {
> +    case TYPE_LOAD:
> +    case TYPE_FPLOAD:
> +    case TYPE_VECLOAD:
> +      pcrel_opt_load (addr_insn, use_insn);
> +      break;
> +
> +    case TYPE_STORE:
> +    case TYPE_FPSTORE:
> +    case TYPE_VECSTORE:
> +      pcrel_opt_store (addr_insn, use_insn);
> +      break;
> +
> +    default:
> +      gcc_unreachable ();
> +    }
> +}
> +
> +/* Optimize pcrel external variable references.  */
> +
> +static unsigned int
> +pcrel_opt_pass (function *fun)
> +{
> +  basic_block bb;
> +  rtx_insn *insn, *curr_insn = 0;
> +
> +  memset ((char *) &counters, '\0', sizeof (counters));
> +
> +  /* Dataflow analysis for use-def chains.  */
> +  df_set_flags (DF_RD_PRUNE_DEAD_DEFS);
> +  df_chain_add_problem (DF_DU_CHAIN + DF_UD_CHAIN);
> +  df_note_add_problem ();
> +  df_analyze ();
> +  df_set_flags (DF_DEFER_INSN_RESCAN | DF_LR_RUN_DCE);
> +
> +  if (dump_file)
> +    fprintf (dump_file, "\n");
> +
> +  /* Look at each basic block to see if there is a load of an external
> +     variable's external address, and a single load/store using that external
> +     address.  */
> +  FOR_ALL_BB_FN (bb, fun)
> +    {
> +      FOR_BB_INSNS_SAFE (bb, insn, curr_insn)
> +	{
> +	  if (NONJUMP_INSN_P (insn)
> +	      && single_set (insn)
> +	      && get_attr_loads_extern_addr (insn) == LOADS_EXTERN_ADDR_YES)
> +	    pcrel_opt_address (insn);
> +	}
> +    }
> +
> +  if (dump_file)
> +    {
> +      fprintf (dump_file,
> +	       "\n# of load(s) of an address of an external symbol = %lu\n",
> +	       counters.extern_addrs);
> +
> +      fprintf (dump_file, "# of PCREL_OPT load(s) = %lu (adjacent %lu)\n",
> +	       counters.loads, counters.adjacent_loads);
> +
> +      if (counters.failed_loads)
> +	fprintf (dump_file, "# of failed PCREL_OPT load(s) = %lu\n",
> +		 counters.failed_loads);
> +
> +      fprintf (dump_file, "# of PCREL_OPT store(s) = %lu (adjacent %lu)\n",
> +	       counters.stores, counters.adjacent_stores);
> +
> +      if (counters.failed_stores)
> +	fprintf (dump_file, "# of failed PCREL_OPT store(s) = %lu\n",
> +		 counters.failed_stores);
> +
> +      fprintf (dump_file, "\n");
> +    }
> +
> +  df_remove_problem (df_chain);
> +  df_process_deferred_rescans ();
> +  df_set_flags (DF_RD_PRUNE_DEAD_DEFS | DF_LR_RUN_DCE);
> +  df_analyze ();
> +  return 0;
> +}
> +
> +/* Optimize pc-relative references for the new PCREL_OPT pass.  */
> +const pass_data pass_data_pcrel_opt =
> +{
> +  RTL_PASS,			/* type.  */
> +  "pcrel_opt",			/* name.  */
> +  OPTGROUP_NONE,		/* optinfo_flags.  */
> +  TV_NONE,			/* tv_id.  */
> +  0,				/* properties_required.  */
> +  0,				/* properties_provided.  */
> +  0,				/* properties_destroyed.  */
> +  0,				/* todo_flags_start.  */
> +  TODO_df_finish,		/* todo_flags_finish.  */
> +};
> +
> +/* Pass data structures.  */
> +class pcrel_opt : public rtl_opt_pass
> +{
> +public:
> +  pcrel_opt (gcc::context *ctxt)
> +  : rtl_opt_pass (pass_data_pcrel_opt, ctxt)
> +  {}
> +
> +  ~pcrel_opt (void)
> +  {}
> +
> +  /* opt_pass methods:  */
> +  virtual bool gate (function *)
> +  {
> +    return (TARGET_PCREL && TARGET_PCREL_OPT && optimize);
> +  }
> +
> +  virtual unsigned int execute (function *fun)
> +  {
> +    return pcrel_opt_pass (fun);
> +  }
> +
> +  opt_pass *clone ()
> +  {
> +    return new pcrel_opt (m_ctxt);
> +  }
> +};
> +
> +rtl_opt_pass *
> +make_pass_pcrel_opt (gcc::context *ctxt)
> +{
> +  return new pcrel_opt (ctxt);
> +}
> diff --git a/gcc/config/rs6000/pcrel-opt.md b/gcc/config/rs6000/pcrel-opt.md
> new file mode 100644
> index 00000000000..95338f9d2fe
> --- /dev/null
> +++ b/gcc/config/rs6000/pcrel-opt.md
> @@ -0,0 +1,386 @@
> +;; Machine description for the PCREL_OPT optimization.
> +;; Copyright (C) 2020 Free Software Foundation, Inc.
> +;; Contributed by Michael Meissner (meissner@linux.ibm.com)
> +
> +;; This file is part of GCC.
> +
> +;; GCC is free software; you can redistribute it and/or modify it
> +;; under the terms of the GNU General Public License as published
> +;; by the Free Software Foundation; either version 3, or (at your
> +;; option) any later version.
> +
> +;; GCC is distributed in the hope that it will be useful, but WITHOUT
> +;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
> +;; or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU General Public
> +;; License for more details.
> +
> +;; You should have received a copy of the GNU General Public License
> +;; along with GCC; see the file COPYING3.  If not see
> +;; <http://www.gnu.org/licenses/>.
> +
> +;; Support for the PCREL_OPT optimization.  PCREL_OPT looks for instances where
> +;; an external variable is used only once, either for reading or for writing.
> +;;
> +;; If we are optimizing a single read, normally the code would look like:
> +;;
> +;;	(set (reg:DI <ptr>)
> +;;	     (symbol_ref:DI "<extern_addr>"))	# <data> is currently dead
> +;;
> +;;		...	# insns do not need to be adjacent
> +;;
> +;;	(set (reg:SI <data>)
> +;;	     (mem:SI (reg:DI <xxx>)))		# <ptr> dies with this insn
> +;;
> +;; We transform this into:
> +;;
> +;;	(parallel [(set (reg:DI <ptr>)
> +;;			(unspec:SI [(symbol_ref:DI <extern_addr>)
> +;;				    (const_int <marker>)]
> +;;				   UNSPEC_PCREL_OPT_LD_ADDR))
> +;;		   (set (reg:DI <data>)
> +;;			(unspec:DI [(const_int 0)]
> +;;				   UNSPEC_PCREL_OPT_LD_ADDR))])
> +;;
> +;;	...
> +;;
> +;;	(parallel [(set (reg:SI <data>)
> +;;		   (unspec:SI [(mem:SI (reg:DI <ptr>))
> +;;			       (reg:DI <data>)
> +;;			       (const_int <marker>)]
> +;;			      UNSPEC_PCREL_OPT_LD))
> +;;		   (clobber (reg:DI <ptr>))])
> +;;
> +;; The marker is an integer constant that links the load of the external
> +;; address to the load of the actual variable.
> +;;
> +;; In the first insn, we set both the address of the external variable, and
> +;; mark that the variable being loaded both are created in that insn, and are
> +;; consumed in the second insn.	 It doesn't matter what mode the register that
> +;; we will ultimately do the load into, so we use DImode.  We just need to mark
> +;; that both registers may be set in the first insn, and will be used in the
> +;; second insn.
> +;;
> +;; Since we use UNSPEC's and link both the the register holding the external
> +;; address and the value being loaded, it should prevent other passes from
> +;; modifying it.
> +;;
> +;; If the register being loaded is the same as the base register, we use an
> +;; alternate form of the insns.
> +;;
> +;;	(set (reg:DI <data_ptr>)
> +;;	     (unspec:DI [(symbol_ref:DI <extern_addr>)
> +;;			 (const_int <marker>)]
> +;;			UNSPEC_PCREL_OPT_LD_ADDR_SAME_REG))
> +;;
> +;;	...
> +;;
> +;;	(parallel [(set (reg:SI <data>)
> +;;		   (unspec:SI [(mem:SI (reg:DI <ptr>))
> +;;			       (reg:DI <data>)
> +;;			       (const_int <marker>)]
> +;;			      UNSPEC_PCREL_OPT_LD))
> +;;		   (clobber (reg:DI <ptr>))])
> +
> +(define_c_enum "unspec"
> +  [UNSPEC_PCREL_OPT_LD_ADDR
> +   UNSPEC_PCREL_OPT_LD_ADDR_SAME_REG
> +   UNSPEC_PCREL_OPT_LD_RELOC
> +   UNSPEC_PCREL_OPT_ST_ADDR
> +   UNSPEC_PCREL_OPT_ST_RELOC])
> +
> +;; Modes that are supported for PCREL_OPT
> +(define_mode_iterator PO [QI HI SI DI TI SF DF KF
> +			  V1TI V2DI V4SI V8HI V16QI V2DF V4SF
> +			  (TF "TARGET_FLOAT128_TYPE && TARGET_IEEEQUAD")])
> +
> +;; Vector modes for PCREL_OPT
> +(define_mode_iterator PO_VECT [TI KF V1TI V2DI V4SI V8HI V16QI V2DF V4SF
> +			       (TF "TARGET_FLOAT128_TYPE && TARGET_IEEEQUAD")])
> +
> +;; Insn for loading the external address, where the register being loaded is not
> +;; the same as the register being loaded with the data.
> +(define_insn "pcrel_opt_ld_addr"
> +  [(set (match_operand:DI 0 "base_reg_operand" "=&b,&b")
> +	(unspec:DI [(match_operand:DI 1 "pcrel_external_address")
> +		    (match_operand 2 "const_int_operand" "n,n")]
> +		   UNSPEC_PCREL_OPT_LD_ADDR))
> +   (set (match_operand:DI 3 "gpc_reg_operand" "=r,wa")
> +	(unspec:DI [(const_int 0)]
> +		   UNSPEC_PCREL_OPT_LD_ADDR))]
> +  "TARGET_PCREL_OPT
> +   && reg_or_subregno (operands[0]) != reg_or_subregno (operands[3])"
> +  "ld %0,%a1\n.Lpcrel%2:"
> +  [(set_attr "prefixed" "yes")
> +   (set_attr "type" "load")
> +   (set_attr "loads_extern_addr" "yes")])
> +
> +;; Alternate form of loading up the external address that is the same register
> +;; as the final load.
> +(define_insn "pcrel_opt_ld_addr_same_reg"
> +  [(set (match_operand:DI 0 "base_reg_operand" "=b")
> +	(unspec:DI [(match_operand:DI 1 "pcrel_external_address")
> +		    (match_operand 2 "const_int_operand" "n")]
> +		   UNSPEC_PCREL_OPT_LD_ADDR_SAME_REG))]
> +  "TARGET_PCREL_OPT"
> +  "ld %0,%a1\n.Lpcrel%2:"
> +  [(set_attr "prefixed" "yes")
> +   (set_attr "type" "load")
> +   (set_attr "loads_extern_addr" "yes")])
> +
> +;; PCREL_OPT modes that are optimized for loading or storing GPRs.
> +(define_mode_iterator PO_GPR [QI HI SI DI SF DF])
> +
> +(define_mode_attr PO_GPR_LD [(QI "lbz")
> +			     (HI "lhz")
> +			     (SI "lwz")
> +			     (SF "lwz")
> +			     (DI "ld")
> +			     (DF "ld")])
> +
> +;; PCREL_OPT load operation of GPRs.  Operand 4 (the register used to hold the
> +;; address of the external symbol) is SCRATCH if the same register is used for
> +;; the normal load.
> +(define_insn "*pcrel_opt_ld<mode>_gpr"
> +  [(parallel [(set (match_operand:PO_GPR 0 "int_reg_operand" "+r")
> +		   (unspec:PO_GPR [(match_operand:PO_GPR 1 "d_form_memory" "o")
> +				   (match_operand:DI 2 "int_reg_operand" "0")
> +				   (match_operand 3 "const_int_operand" "n")]
> +				  UNSPEC_PCREL_OPT_LD_RELOC))
> +	      (clobber (match_scratch:DI 4 "=bX"))])]
> +  "TARGET_PCREL_OPT
> +   && (GET_CODE (operands[4]) == SCRATCH
> +       || reg_mentioned_p (operands[4], operands[1]))"
> +{
> +  output_pcrel_opt_reloc (operands[3]);
> +  return "<PO_GPR_LD> %0,%1";
> +}
> +  [(set_attr "type" "load")])
> +
> +;; PCREL_OPT load with sign/zero extension
> +(define_insn "*pcrel_opt_ldsi_<u><mode>_gpr"
> +  [(set (match_operand:EXTSI 0 "int_reg_operand" "+r")
> +	(any_extend:EXTSI
> +	 (unspec:SI [(match_operand:SI 1 "d_form_memory" "o")
> +		     (match_operand:DI 2 "int_reg_operand" "0")
> +		     (match_operand 3 "const_int_operand" "n")]
> +		     UNSPEC_PCREL_OPT_LD_RELOC)))
> +   (clobber (match_scratch:DI 4 "=bX"))]
> +  "TARGET_PCREL_OPT"
> +{
> +  output_pcrel_opt_reloc (operands[3]);
> +  return "lw<az> %0,%1";
> +}
> +  [(set_attr "type" "load")])
> +
> +(define_insn "*pcrel_opt_ldhi_<u><mode>_gpr"
> +  [(set (match_operand:EXTHI 0 "int_reg_operand" "+r")
> +	(any_extend:EXTHI
> +	 (unspec:HI [(match_operand:HI 1 "d_form_memory" "o")
> +		     (match_operand:DI 2 "int_reg_operand" "0")
> +		     (match_operand 3 "const_int_operand" "n")]
> +		     UNSPEC_PCREL_OPT_LD_RELOC)))
> +   (clobber (match_scratch:DI 4 "=bX"))]
> +  "TARGET_PCREL_OPT"
> +{
> +  output_pcrel_opt_reloc (operands[3]);
> +  return "lh<az> %0,%1";
> +}
> +  [(set_attr "type" "load")])
> +
> +(define_insn "*pcrel_opt_ldqi_u<mode>_gpr"
> +  [(set (match_operand:EXTQI 0 "int_reg_operand" "+r")
> +	(zero_extend:EXTQI
> +	 (unspec:QI [(match_operand:QI 1 "d_form_memory" "o")
> +		     (match_operand:DI 2 "int_reg_operand" "0")
> +		     (match_operand 3 "const_int_operand" "n")]
> +		     UNSPEC_PCREL_OPT_LD_RELOC)))
> +   (clobber (match_scratch:DI 4 "=bX"))]
> +  "TARGET_PCREL_OPT"
> +{
> +  output_pcrel_opt_reloc (operands[3]);
> +  return "lbz %0,%1";
> +}
> +  [(set_attr "type" "load")])
> +
> +;; Scalar types that can be optimized by loading them into floating point
> +;; or Altivec registers.
> +(define_mode_iterator PO_FP [DI DF SF])
> +
> +;; Load instructions to load up scalar floating point or 64-bit integer values
> +;; into floating point registers or Altivec registers.
> +(define_mode_attr PO_FPR_LD [(DI "lfd")	 (DF "lfd")  (SF "lfs")])
> +(define_mode_attr PO_AVX_LD [(DI "lxsd") (DF "lxsd") (SF "lxssp")])
> +
> +;; PCREL_OPT load operation of scalar DF/DI/SF into vector registers.
> +(define_insn "*pcrel_opt_ld<mode>_vsx"
> +  [(set (match_operand:PO_FP 0 "vsx_register_operand" "+d,v")
> +	(unspec:PO_FP [(match_operand:PO_FP 1 "d_form_memory" "o,o")
> +		       (match_operand:DI 2 "vsx_register_operand" "0,0")
> +		       (match_operand 3 "const_int_operand" "n,n")]
> +		       UNSPEC_PCREL_OPT_LD_RELOC))
> +   (clobber (match_operand:DI 4 "base_reg_operand" "=b,b"))]
> +  "TARGET_PCREL_OPT"
> +{
> +  output_pcrel_opt_reloc (operands[3]);
> +  return which_alternative ? "<PO_AVX_LD> %0,%1" : "<PO_FPR_LD> %0,%1";
> +}
> +  [(set_attr "type" "fpload")])
> +
> +;; PCREL_OPT optimization extending SFmode to DFmode via a load.
> +(define_insn "*pcrel_opt_ldsf_df"
> +  [(set (match_operand:DF 0 "vsx_register_operand" "+d,v")
> +	(float_extend:DF
> +	 (unspec:SF [(match_operand:SF 1 "d_form_memory" "o,o")
> +		     (match_operand:DI 2 "vsx_register_operand" "0,0")
> +		     (match_operand 3 "const_int_operand" "n,n")]
> +		    UNSPEC_PCREL_OPT_LD_RELOC)))
> +   (clobber (match_operand:DI 4 "base_reg_operand" "=b,b"))]
> +  "TARGET_PCREL_OPT"
> +{
> +  output_pcrel_opt_reloc (operands[3]);
> +  return which_alternative ? "lxssp %0,%1" : "lfs %0,%1";
> +}
> +  [(set_attr "type" "fpload")])
> +
> +;; PCREL_OPT load operation of vector/float128 types into vector registers.
> +(define_insn "*pcrel_opt_ld<mode>"
> +  [(set (match_operand:PO_VECT 0 "vsx_register_operand" "+wa")
> +	(unspec:PO_VECT [(match_operand:PO_VECT 1 "d_form_memory" "o")
> +			 (match_operand:DI 2 "vsx_register_operand" "0")
> +			 (match_operand 3 "const_int_operand" "n")]
> +			UNSPEC_PCREL_OPT_LD_RELOC))
> +   (clobber (match_operand:DI 4 "base_reg_operand" "=b"))]
> +  "TARGET_PCREL_OPT"
> +{
> +  output_pcrel_opt_reloc (operands[3]);
> +  return "lxv %x0,%1";
> +}
> +  [(set_attr "type" "vecload")])
> +
> +
> +;; PCREL_OPT optimization for stores.  We need to put the label after the PLD
> +;; instruction, because the assembler might insert a NOP before the PLD for
> +;; alignment.
> +;;
> +;; If we are optimizing a single write, normally the code would look like:
> +;;
> +;;	(set (reg:DI <ptr>)
> +;;	     (symbol_ref:DI "<extern_addr>"))	# <data> must be live here
> +;;
> +;;	    ...		     # insns do not need to be adjacent
> +;;
> +;;	(set (mem:SI (reg:DI <xxx>))
> +;;	     (reg:SI <data>))			# <ptr> dies with this insn
> +;;
> +;; We optimize this to be:
> +;;
> +;;	(parallel [(set (reg:DI <ptr>)
> +;;			(unspec:DI [(symbol_ref:DI "<extern_addr>")
> +;;				    (const_int <marker>)]
> +;;				   UNSPEC_PCREL_OPT_ST_ADDR))
> +;;		   (use (reg:<MODE> <data>))])
> +;;
> +;;	    ...		     # insns do not need to be adjacent
> +;;
> +;;	(parallel [(set (mem:<MODE> (reg:DI <ptr>))
> +;;			(unspec:<MODE> [(reg:<MODE> <data>)
> +;;					(const_int <marker>)]
> +;;				       UNSPEC_PCREL_OPT_ST_RELOC))
> +;;		   (clobber (reg:DI <ptr>))])
> +
> +(define_insn "*pcrel_opt_st_addr<mode>"
> +  [(set (match_operand:DI 0 "gpc_reg_operand" "=b")
> +	(unspec:DI [(match_operand:DI 1 "pcrel_external_address")
> +		    (match_operand 2 "const_int_operand" "n")]
> +		UNSPEC_PCREL_OPT_ST_ADDR))
> +   (use (match_operand:PO 3 "gpc_reg_operand" "rwa"))]
> +  "TARGET_PCREL_OPT"
> +  "ld %0,%a1\n.Lpcrel%2:"
> +  [(set_attr "prefixed" "yes")
> +   (set_attr "type" "load")
> +   (set_attr "loads_extern_addr" "yes")])
> +
> +;; PCREL_OPT stores.
> +(define_insn "*pcrel_opt_st<mode>"
> +  [(set (match_operand:QHSI 0 "d_form_memory" "=o")
> +	(unspec:QHSI [(match_operand:QHSI 1 "gpc_reg_operand" "r")
> +		      (match_operand 2 "const_int_operand" "n")]
> +		     UNSPEC_PCREL_OPT_ST_RELOC))
> +   (clobber (match_operand:DI 3 "base_reg_operand" "=b"))]
> +  "TARGET_PCREL_OPT"
> +{
> +  output_pcrel_opt_reloc (operands[2]);
> +  return "st<wd> %1,%0";
> +}
> +  [(set_attr "type" "store")])
> +
> +(define_insn "*pcrel_opt_stdi"
> +  [(set (match_operand:DI 0 "d_form_memory" "=o,o,o")
> +	(unspec:DI [(match_operand:DI 1 "gpc_reg_operand" "r,d,v")
> +		    (match_operand 2 "const_int_operand" "n,n,n")]
> +		   UNSPEC_PCREL_OPT_ST_RELOC))
> +   (clobber (match_operand:DI 3 "base_reg_operand" "=b,b,b"))]
> +  "TARGET_PCREL_OPT && TARGET_POWERPC64"
> +{
> +  output_pcrel_opt_reloc (operands[2]);
> +  switch (which_alternative)
> +    {
> +    case 0: return "std %1,%0";
> +    case 1: return "stfd %1,%0";
> +    case 2: return "stxsd %1,%0";
> +    default: gcc_unreachable ();
> +    }
> +}
> +  [(set_attr "type" "store,fpstore,fpstore")])
> +
> +(define_insn "*pcrel_opt_stsf"
> +  [(set (match_operand:SF 0 "d_form_memory" "=o,o,o")
> +	(unspec:SF [(match_operand:SF 1 "gpc_reg_operand" "d,v,r")
> +		    (match_operand 2 "const_int_operand" "n,n,n")]
> +		   UNSPEC_PCREL_OPT_ST_RELOC))
> +   (clobber (match_operand:DI 3 "base_reg_operand" "=b,b,b"))]
> +  "TARGET_PCREL_OPT"
> +{
> +  output_pcrel_opt_reloc (operands[2]);
> +  switch (which_alternative)
> +    {
> +    case 0: return "stfs %1,%0";
> +    case 1: return "stxssp %1,%0";
> +    case 2: return "stw %1,%0";
> +    default: gcc_unreachable ();
> +    }
> +}
> +  [(set_attr "type" "fpstore,fpstore,store")])
> +
> +(define_insn "*pcrel_opt_stdf"
> +  [(set (match_operand:DF 0 "d_form_memory" "=o,o,o")
> +	(unspec:DF [(match_operand:DF 1 "gpc_reg_operand" "d,v,r")
> +		    (match_operand 2 "const_int_operand" "n,n,n")]
> +		   UNSPEC_PCREL_OPT_ST_RELOC))
> +   (clobber (match_operand:DI 3 "base_reg_operand" "=b,b,b"))]
> +  "TARGET_PCREL_OPT
> +   && (TARGET_POWERPC64 || vsx_register_operand (operands[1], DFmode))"
> +{
> +  output_pcrel_opt_reloc (operands[2]);
> +  switch (which_alternative)
> +    {
> +    case 0: return "stfd %1,%0";
> +    case 1: return "stxsd %1,%0";
> +    case 2: return "std %1,%0";
> +    default: gcc_unreachable ();
> +    }
> +}
> +  [(set_attr "type" "fpstore,fpstore,store")])
> +
> +(define_insn "*pcrel_opt_st<mode>"
> +  [(set (match_operand:PO_VECT 0 "d_form_memory" "=o")
> +	(unspec:PO_VECT [(match_operand:PO_VECT 1 "gpc_reg_operand" "wa")
> +		     (match_operand 2 "const_int_operand" "n")]
> +		    UNSPEC_PCREL_OPT_ST_RELOC))
> +   (clobber (match_operand:DI 3 "base_reg_operand" "=b"))]
> +  "TARGET_PCREL_OPT"
> +{
> +  output_pcrel_opt_reloc (operands[2]);
> +  return "stxv %x1,%0";
> +}
> +  [(set_attr "type" "vecstore")])
> diff --git a/gcc/config/rs6000/predicates.md b/gcc/config/rs6000/predicates.md
> index 4c2fe7fa312..9610587e1c1 100644
> --- a/gcc/config/rs6000/predicates.md
> +++ b/gcc/config/rs6000/predicates.md
> @@ -1876,3 +1876,26 @@ (define_predicate "prefixed_memory"
> {
>   return address_is_prefixed (XEXP (op, 0), mode, NON_PREFIXED_DEFAULT);
> })
> +
> +;; Return true if the operand is a valid memory operand with an offsettable
> +;; address that could be merged with the load of a PC-relative external address
> +;; with the PCREL_OPT optimization.  We don't check here whether or not the
> +;; offset needs to be used in a DS-FORM (bottom 2 bits 0) or DQ-FORM (bottom 4
> +;; bits 0) instruction.
> +(define_predicate "d_form_memory"
> +  (match_code "mem")
> +{
> +  if (!memory_operand (op, mode))
> +    return false;
> +
> +  rtx addr = XEXP (op, 0);
> +
> +  if (REG_P (addr) || SUBREG_P (addr))
> +    return true;
> +
> +  if (GET_CODE (addr) != PLUS)
> +    return false;
> +
> +  return (base_reg_operand (XEXP (addr, 0), Pmode)
> +	  && satisfies_constraint_I (XEXP (addr, 1)));
> +})
> diff --git a/gcc/config/rs6000/rs6000-cpus.def b/gcc/config/rs6000/rs6000-cpus.def
> index 8d2c1ffd6cf..d3f72d77a6e 100644
> --- a/gcc/config/rs6000/rs6000-cpus.def
> +++ b/gcc/config/rs6000/rs6000-cpus.def
> @@ -78,6 +78,7 @@
> /* Flags that need to be turned off if -mno-power10.  */
> #define OTHER_POWER10_MASKS	(OPTION_MASK_MMA			\
> 				 | OPTION_MASK_PCREL			\
> +				 | OPTION_MASK_PCREL_OPT		\
> 				 | OPTION_MASK_PREFIXED)
> 
> #define ISA_3_1_MASKS_SERVER	(ISA_3_0_MASKS_SERVER			\
> @@ -142,6 +143,7 @@
> 				 | OPTION_MASK_P9_MISC			\
> 				 | OPTION_MASK_P9_VECTOR		\
> 				 | OPTION_MASK_PCREL			\
> +				 | OPTION_MASK_PCREL_OPT		\
> 				 | OPTION_MASK_POPCNTB			\
> 				 | OPTION_MASK_POPCNTD			\
> 				 | OPTION_MASK_POWERPC64		\
> diff --git a/gcc/config/rs6000/rs6000-passes.def b/gcc/config/rs6000/rs6000-passes.def
> index 5164c526e34..b62244b8df2 100644
> --- a/gcc/config/rs6000/rs6000-passes.def
> +++ b/gcc/config/rs6000/rs6000-passes.def
> @@ -24,4 +24,12 @@ along with GCC; see the file COPYING3.  If not see
>    REPLACE_PASS (PASS, INSTANCE, TGT_PASS)
>  */
> 
> +  /* Pass to add the appropriate vector swaps on power8 little endian systems.
> +     The power8 does not have instructions that automaticaly do the byte swaps
> +     for loads and stores.  */
>   INSERT_PASS_BEFORE (pass_cse, 1, pass_analyze_swaps);
> +
> +  /* Pass to do the PCREL_OPT optimization that combines the load of an
> +     external symbol's address along with a single load or store using that
> +     address as a base register.  */
> +  INSERT_PASS_BEFORE (pass_sched2, 1, pass_pcrel_opt);
> diff --git a/gcc/config/rs6000/rs6000-protos.h b/gcc/config/rs6000/rs6000-protos.h
> index 25fa5dd57cd..75c659971ea 100644
> --- a/gcc/config/rs6000/rs6000-protos.h
> +++ b/gcc/config/rs6000/rs6000-protos.h
> @@ -190,10 +190,13 @@ enum non_prefixed_form {
> 
> extern enum insn_form address_to_insn_form (rtx, machine_mode,
> 					    enum non_prefixed_form);
> +extern enum non_prefixed_form reg_to_non_prefixed (rtx, machine_mode);
> +extern bool offsettable_non_prefixed_memory (rtx, machine_mode, rtx);
> extern bool prefixed_load_p (rtx_insn *);
> extern bool prefixed_store_p (rtx_insn *);
> extern bool prefixed_paddi_p (rtx_insn *);
> extern void rs6000_asm_output_opcode (FILE *);
> +extern void output_pcrel_opt_reloc (rtx);
> extern void rs6000_final_prescan_insn (rtx_insn *, rtx [], int);
> extern int rs6000_adjust_insn_length (rtx_insn *, int);
> 
> @@ -306,6 +309,7 @@ namespace gcc { class context; }
> class rtl_opt_pass;
> 
> extern rtl_opt_pass *make_pass_analyze_swaps (gcc::context *);
> +extern rtl_opt_pass *make_pass_pcrel_opt (gcc::context *);
> extern bool rs6000_sum_of_two_registers_p (const_rtx expr);
> extern bool rs6000_quadword_masked_address_p (const_rtx exp);
> extern rtx rs6000_gen_lvx (enum machine_mode, rtx, rtx);
> diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> index 1e506b83762..2c09d33bd74 100644
> --- a/gcc/config/rs6000/rs6000.c
> +++ b/gcc/config/rs6000/rs6000.c
> @@ -1173,7 +1173,6 @@ static bool rs6000_secondary_reload_move (enum rs6000_reg_type,
> 					  machine_mode,
> 					  secondary_reload_info *,
> 					  bool);
> -static enum non_prefixed_form reg_to_non_prefixed (rtx reg, machine_mode mode);
> rtl_opt_pass *make_pass_analyze_swaps (gcc::context*);
> 
> /* Hash table stuff for keeping track of TOC entries.  */
> @@ -4435,6 +4434,14 @@ rs6000_option_override_internal (bool global_init_p)
>       rs6000_isa_flags &= ~OPTION_MASK_MMA;
>     }
> 
> +  if (!TARGET_PCREL && TARGET_PCREL_OPT)
> +    {
> +      if ((rs6000_isa_flags_explicit & OPTION_MASK_PCREL_OPT) != 0)
> +	error ("%qs requires %qs", "-mpcrel-opt", "-mpcrel");
> +
> +	rs6000_isa_flags &= ~OPTION_MASK_PCREL_OPT;
> +    }
> +
>   if (TARGET_DEBUG_REG || TARGET_DEBUG_TARGET)
>     rs6000_print_isa_options (stderr, 0, "after subtarget", rs6000_isa_flags);
> 
> @@ -8634,8 +8641,57 @@ rs6000_delegitimize_address (rtx orig_x)
> {
>   rtx x, y, offset;
> 
> -  if (GET_CODE (orig_x) == UNSPEC && XINT (orig_x, 1) == UNSPEC_FUSION_GPR)
> -    orig_x = XVECEXP (orig_x, 0, 0);
> +  /* UNSPEC_FUSION_GPR is created by the peephole2 for power8 fusion.  It
> +     encodes loading up the high part of the address of a TOC reference along
> +     with a load of a GPR using the same base register used for the load.  We
> +     return the original SYMBOL_REF.
> +
> +	(set (reg:INT1 <reg>
> +	     (unspec:INT1 [<combined-address>] UNSPEC_FUSION_GPR)))
> +
> +     UNSPEC_PCREL_OPT_LD_ADDR is used by the power10 PCREL_OPT pass.  These
> +     UNSPECs include the external SYMBOL_REF along with the value being loaded.
> +     We return the original SYMBOL_REF.
> +
> +	(parallel [(set (reg:DI <base-reg>)
> +			(unspec:DI [(symbol_ref <symbol>)
> +				    (const_int <marker>)]
> +				   UNSPEC_PCREL_OPT_LD_ADDR))
> +		   (set (reg:DI <load-reg>)
> +			(unspec:DI [(const_int 0)]
> +				   UNSPEC_PCREL_OPT_LD_ADDR))])
> +
> +     UNSPEC_PCREL_OPT_LD_ADDR_SAME_REG is an alternative that is used if the
> +     GPR being loaded is the same as the GPR used to hold the external address.
> +
> +	(set (reg:DI <base-reg>)
> +	     (unspec:DI [(symbol_ref <symbol>)
> +			 (const_int <marker>)]
> +			UNSPEC_PCREL_OPT_LD_ADDR_SAME_REG))
> +
> +     UNSPEC_PCREL_OPT_ST_ADDR is used by the power10 PCREL_OPT pass.  This
> +     UNSPEC include the external SYMBOL_REF along with the value being loaded.
> +     We return the original SYMBOL_REF.
> +
> +	(parallel [(set (reg:DI <base-reg>)
> +			(unspec:DI [(symbol_ref <symbol>)
> +				    (const_int <marker>)]
> +				   UNSPEC_PCREL_OPT_ST_ADDR))
> +		   (use (reg <store-reg>))])  */
> +
> +  if (GET_CODE (orig_x) == UNSPEC)
> +    switch (XINT (orig_x, 1))
> +      {
> +      case UNSPEC_FUSION_GPR:
> +      case UNSPEC_PCREL_OPT_LD_ADDR:
> +      case UNSPEC_PCREL_OPT_LD_ADDR_SAME_REG:
> +      case UNSPEC_PCREL_OPT_ST_ADDR:
> +	orig_x = XVECEXP (orig_x, 0, 0);
> +	break;
> +
> +      default:
> +	break;
> +      }
> 
>   orig_x = delegitimize_mem_from_attrs (orig_x);
> 
> @@ -23391,6 +23447,7 @@ static struct rs6000_opt_mask const rs6000_opt_masks[] =
>   { "mulhw",			OPTION_MASK_MULHW,		false, true  },
>   { "multiple",			OPTION_MASK_MULTIPLE,		false, true  },
>   { "pcrel",			OPTION_MASK_PCREL,		false, true  },
> +  { "pcrel-opt",		OPTION_MASK_PCREL_OPT,		false, true  },
>   { "popcntb",			OPTION_MASK_POPCNTB,		false, true  },
>   { "popcntd",			OPTION_MASK_POPCNTD,		false, true  },
>   { "power8-fusion",		OPTION_MASK_P8_FUSION,		false, true  },
> @@ -25490,6 +25547,32 @@ address_to_insn_form (rtx addr,
>   return INSN_FORM_BAD;
> }
> 
> +/* Return true if an REG with a given MODE is loaded from or stored into a MEM
> +   location uses a non-prefixed offsettable address.  This is used to validate
> +   the load or store with the PCREL_OPT optimization to make sure it is an
> +   instruction that can be optimized.
> +
> +   We need to specify the MODE separately from the REG to allow for loads that
> +   include zero/sign/float extension.  */
> +
> +bool
> +offsettable_non_prefixed_memory (rtx reg, machine_mode mode, rtx mem)
> +{
> +  /* If the instruction is indexed only like LFIWAX/LXSIWAX, it is not
> +     offsettable.  */
> +  enum non_prefixed_form non_prefixed = reg_to_non_prefixed (reg, mode);
> +  if (non_prefixed == NON_PREFIXED_X)
> +    return false;
> +
> +  /* Check if this is a non-prefixed offsettable instruction.  */
> +  rtx addr = XEXP (mem, 0);
> +  enum insn_form iform = address_to_insn_form (addr, mode, non_prefixed);
> +  return (iform == INSN_FORM_BASE_REG
> +	  || iform == INSN_FORM_D
> +	  || iform == INSN_FORM_DS
> +	  || iform == INSN_FORM_DQ);
> +}
> +
> /* Helper function to see if we're potentially looking at lfs/stfs.
>    - PARALLEL containing a SET and a CLOBBER
>    - stfs:
> @@ -25548,7 +25631,7 @@ is_lfs_stfs_insn (rtx_insn *insn)
> /* Helper function to take a REG and a MODE and turn it into the non-prefixed
>    instruction format (D/DS/DQ) used for offset memory.  */
> 
> -static enum non_prefixed_form
> +enum non_prefixed_form
> reg_to_non_prefixed (rtx reg, machine_mode mode)
> {
>   /* If it isn't a register, use the defaults.  */
> @@ -25771,11 +25854,34 @@ void
> rs6000_asm_output_opcode (FILE *stream)
> {
>   if (next_insn_prefixed_p)
> -    fprintf (stream, "p");
> +    {
> +      fprintf (stream, "p");
> +
> +      /* Reset flag in case there are separate insn lines in the sequence, so
> +	 the 'p' is only emited for the first line.  This shows up when we are
> +	 doing the PCREL_OPT optimization, in that the label created with %r<n>
> +	 would have a leading 'p' printed.  */
> +      next_insn_prefixed_p = false;
> +    }
> 
>   return;
> }
> 
> +/* Emit the relocation to tie the next instruction to a previous instruction
> +   that loads up an external address.  This is used to do the PCREL_OPT
> +   optimization.  Note, the label is generated after the PLD of the got
> +   pc-relative address to allow for the assembler to insert NOPs before the PLD
> +   instruction.  The operand is a constant integer that is the label
> +   number.  */
> +
> +void
> +output_pcrel_opt_reloc (rtx label_num)
> +{
> +  rtx operands[1] = { label_num };
> +  output_asm_insn (".reloc .Lpcrel%0-8,R_PPC64_PCREL_OPT,.-(.Lpcrel%0-8)",
> +		   operands);
> +}
> +
> /* Adjust the length of an INSN.  LENGTH is the currently-computed length and
>    should be adjusted to reflect any required changes.  This macro is used when
>    there is some systematic length adjustment required that would be difficult
> diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
> index dc060143104..adc8365df01 100644
> --- a/gcc/config/rs6000/rs6000.md
> +++ b/gcc/config/rs6000/rs6000.md
> @@ -292,6 +292,10 @@ (define_attr "prefixed" "no,yes"
> 
> 	(const_string "no")))
> 
> +;; Whether an insn loads an external address for the PCREL_OPT optimizaton.
> +(define_attr "loads_extern_addr" "no,yes"
> +  (const_string "no"))
> +
> ;; Return the number of real hardware instructions in a combined insn.  If it
> ;; is 0, just use the length / 4.
> (define_attr "num_insns" "" (const_int 0))
> @@ -10226,7 +10230,8 @@ (define_insn "*pcrel_extern_addr"
>   "TARGET_PCREL"
>   "ld %0,%a1"
>   [(set_attr "prefixed" "yes")
> -   (set_attr "type" "load")])
> +   (set_attr "type" "load")
> +   (set_attr "loads_extern_addr" "yes")])
> 
> ;; TOC register handling.
> 
> @@ -14883,3 +14888,4 @@ (define_insn "*cmpeqb_internal"
> (include "dfp.md")
> (include "crypto.md")
> (include "htm.md")
> +(include "pcrel-opt.md")
> diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
> index b2a70e88ca8..d1719bfd2a0 100644
> --- a/gcc/config/rs6000/rs6000.opt
> +++ b/gcc/config/rs6000/rs6000.opt
> @@ -586,6 +586,10 @@ mpcrel
> Target Report Mask(PCREL) Var(rs6000_isa_flags)
> Generate (do not generate) pc-relative memory addressing.
> 
> +mpcrel-opt
> +Target Undocumented Mask(PCREL_OPT) Var(rs6000_isa_flags)
> +Generate (do not generate) pc-relative memory optimizations for externals.
> +
> mmma
> Target Report Mask(MMA) Var(rs6000_isa_flags)
> Generate (do not generate) MMA instructions.
> diff --git a/gcc/config/rs6000/t-rs6000 b/gcc/config/rs6000/t-rs6000
> index 1ddb5729cb2..a617276484e 100644
> --- a/gcc/config/rs6000/t-rs6000
> +++ b/gcc/config/rs6000/t-rs6000
> @@ -23,6 +23,10 @@ TM_H += $(srcdir)/config/rs6000/rs6000-cpus.def
> TM_H += $(srcdir)/config/rs6000/rs6000-modes.h
> PASSES_EXTRA += $(srcdir)/config/rs6000/rs6000-passes.def
> 
> +pcrel-opt.o: $(srcdir)/config/rs6000/pcrel-opt.c
> +	$(COMPILE) $<
> +	$(POSTCOMPILE)
> +
> rs6000-c.o: $(srcdir)/config/rs6000/rs6000-c.c
> 	$(COMPILE) $<
> 	$(POSTCOMPILE)
> @@ -86,4 +90,5 @@ MD_INCLUDES = $(srcdir)/config/rs6000/rs64.md \
> 	$(srcdir)/config/rs6000/mma.md \
> 	$(srcdir)/config/rs6000/crypto.md \
> 	$(srcdir)/config/rs6000/htm.md \
> -	$(srcdir)/config/rs6000/dfp.md
> +	$(srcdir)/config/rs6000/dfp.md \
> +	$(srcdir)/config/rs6000/pcrel-opt.md
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-inc-di.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-inc-di.c
> new file mode 100644
> index 00000000000..f165068e2be
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-inc-di.c
> @@ -0,0 +1,18 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-require-effective-target lp64 } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	unsigned int
> +
> +/* Test whether using an external variable twice (doing an increment) prevents
> +   the PCREL_OPT optimization.  */
> +extern TYPE ext;
> +
> +void
> +inc (void)
> +{
> +  ext++;		/* No PCREL_OPT (uses address twice).  */
> +}
> +
> +/* { dg-final { scan-assembler-not "R_PPC64_PCREL_OPT" } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-df.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-df.c
> new file mode 100644
> index 00000000000..d35862fcb6e
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-df.c
> @@ -0,0 +1,36 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	double
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for
> +   double.  */
> +extern TYPE ext[];
> +
> +TYPE
> +get (void)
> +{
> +  return ext[0];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get2 (void)
> +{
> +  return ext[2];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get_large (void)
> +{
> +  return ext[LARGE];		/* No PCREL_OPT (load is  prefixed).  */
> +}
> +
> +TYPE
> +get_variable (unsigned long n)
> +{
> +  return ext[n];		/* No PCREL_OPT (load is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-di.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-di.c
> new file mode 100644
> index 00000000000..12b51ab2e67
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-di.c
> @@ -0,0 +1,43 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-require-effective-target lp64 } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	long long
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for long
> +   long.  */
> +extern TYPE ext[];
> +
> +TYPE
> +get (void)
> +{
> +  return ext[0];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get2 (void)
> +{
> +  return ext[2];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get_large (void)
> +{
> +  return ext[LARGE];		/* No PCREL_OPT (load is  prefixed).  */
> +}
> +
> +TYPE
> +get_variable (unsigned long n)
> +{
> +  return ext[n];		/* No PCREL_OPT (load is indexed).  */
> +}
> +
> +double
> +get_double (void)
> +{
> +  return (double) ext[0];	/* PCREL_OPT relocation.  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  3 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-hi.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-hi.c
> new file mode 100644
> index 00000000000..4143aeb7371
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-hi.c
> @@ -0,0 +1,42 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	unsigned short
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for unsigned
> +   short.  */
> +extern TYPE ext[];
> +
> +TYPE
> +get (void)
> +{
> +  return ext[0];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get2 (void)
> +{
> +  return ext[2];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get_large (void)
> +{
> +  return ext[LARGE];		/* No PCREL_OPT (load is  prefixed).  */
> +}
> +
> +TYPE
> +get_variable (unsigned long n)
> +{
> +  return ext[n];		/* No PCREL_OPT (load is indexed).  */
> +}
> +
> +double
> +get_double (void)
> +{
> +  return (double) ext[0];	/* No PCREL_OPT (LXSIHZX is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-qi.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-qi.c
> new file mode 100644
> index 00000000000..30d3236f95c
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-qi.c
> @@ -0,0 +1,42 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	unsigned char
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for unsigned
> +   char.  */
> +extern TYPE ext[];
> +
> +TYPE
> +get (void)
> +{
> +  return ext[0];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get2 (void)
> +{
> +  return ext[2];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get_large (void)
> +{
> +  return ext[LARGE];		/* No PCREL_OPT (load is  prefixed).  */
> +}
> +
> +TYPE
> +get_variable (unsigned long n)
> +{
> +  return ext[n];		/* No PCREL_OPT (load is indexed).  */
> +}
> +
> +double
> +get_double (void)
> +{
> +  return (double) ext[0];	/* No PCREL_OPT (LXSIBZX is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-sf.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-sf.c
> new file mode 100644
> index 00000000000..9d1e2a1956f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-sf.c
> @@ -0,0 +1,42 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	float
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for
> +   float.  */
> +extern TYPE ext[];
> +
> +TYPE
> +get (void)
> +{
> +  return ext[0];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get2 (void)
> +{
> +  return ext[2];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get_large (void)
> +{
> +  return ext[LARGE];		/* No PCREL_OPT (load is  prefixed).  */
> +}
> +
> +TYPE
> +get_variable (unsigned long n)
> +{
> +  return ext[n];		/* No PCREL_OPT (load is indexed).  */
> +}
> +
> +double
> +get_double (void)
> +{
> +  return (double) ext[0];	/* PCREL_OPT relocation.  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  3 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-si.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-si.c
> new file mode 100644
> index 00000000000..17be6fa1778
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-si.c
> @@ -0,0 +1,41 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	int
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for int.  */
> +extern TYPE ext[];
> +
> +TYPE
> +get (void)
> +{
> +  return ext[0];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get2 (void)
> +{
> +  return ext[2];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get_large (void)
> +{
> +  return ext[LARGE];		/* No PCREL_OPT (load is  prefixed).  */
> +}
> +
> +TYPE
> +get_variable (unsigned long n)
> +{
> +  return ext[n];		/* No PCREL_OPT (load is indexed).  */
> +}
> +
> +double
> +get_double (void)
> +{
> +  return (double) ext[0];	/* No PCREL_OPT (LFIWAX is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-vector.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-vector.c
> new file mode 100644
> index 00000000000..8c12aea5acd
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-ld-vector.c
> @@ -0,0 +1,36 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	vector double
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for
> +   vector double.  */
> +extern TYPE ext[];
> +
> +TYPE
> +get (void)
> +{
> +  return ext[0];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get2 (void)
> +{
> +  return ext[2];		/* PCREL_OPT relocation.  */
> +}
> +
> +TYPE
> +get_large (void)
> +{
> +  return ext[LARGE];		/* No PCREL_OPT (load is  prefixed).  */
> +}
> +
> +TYPE
> +get_variable (unsigned long n)
> +{
> +  return ext[n];		/* No PCREL_OPT (load is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-df.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-df.c
> new file mode 100644
> index 00000000000..d795d35d8de
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-df.c
> @@ -0,0 +1,36 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	double
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for
> +   double.  */
> +extern TYPE ext[];
> +
> +void
> +store (TYPE a)
> +{
> +  ext[0] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store2 (TYPE a)
> +{
> +  ext[2] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store_large (TYPE a)
> +{
> +  ext[LARGE] = a;		/* No PCREL_OPT (store is prefixed).  */
> +}
> +
> +void
> +store_variable (TYPE a, unsigned long n)
> +{
> +  ext[n] = a;			/* No PCREL_OPT (store is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-di.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-di.c
> new file mode 100644
> index 00000000000..47554394cf7
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-di.c
> @@ -0,0 +1,37 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-require-effective-target lp64 } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	long long
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for long
> +   long.  */
> +extern TYPE ext[];
> +
> +void
> +store (TYPE a)
> +{
> +  ext[0] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store2 (TYPE a)
> +{
> +  ext[2] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store_large (TYPE a)
> +{
> +  ext[LARGE] = a;		/* No PCREL_OPT (store is prefixed).  */
> +}
> +
> +void
> +store_variable (TYPE a, unsigned long n)
> +{
> +  ext[n] = a;			/* No PCREL_OPT (store is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-hi.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-hi.c
> new file mode 100644
> index 00000000000..8822e767dfe
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-hi.c
> @@ -0,0 +1,42 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	unsigned short
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for unsigned
> +   short.  */
> +extern TYPE ext[];
> +
> +void
> +store (TYPE a)
> +{
> +  ext[0] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store2 (TYPE a)
> +{
> +  ext[2] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store_large (TYPE a)
> +{
> +  ext[LARGE] = a;		/* No PCREL_OPT (store is prefixed).  */
> +}
> +
> +void
> +store_variable (TYPE a, unsigned long n)
> +{
> +  ext[n] = a;			/* No PCREL_OPT (store is indexed).  */
> +}
> +
> +void
> +store_double (double a)
> +{
> +  ext[0] = (TYPE) a;		/* No PCREL_OPT (STXIHZX is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-qi.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-qi.c
> new file mode 100644
> index 00000000000..2f756833717
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-qi.c
> @@ -0,0 +1,42 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	unsigned char
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for unsigned
> +   char.  */
> +extern TYPE ext[];
> +
> +void
> +store (TYPE a)
> +{
> +  ext[0] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store2 (TYPE a)
> +{
> +  ext[2] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store_large (TYPE a)
> +{
> +  ext[LARGE] = a;		/* No PCREL_OPT (store is prefixed).  */
> +}
> +
> +void
> +store_variable (TYPE a, unsigned long n)
> +{
> +  ext[n] = a;			/* No PCREL_OPT (store is indexed).  */
> +}
> +
> +void
> +store_double (double a)
> +{
> +  ext[0] = (TYPE) a;		/* No PCREL_OPT (STXIBZX is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-sf.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-sf.c
> new file mode 100644
> index 00000000000..3dd88aad856
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-sf.c
> @@ -0,0 +1,36 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	float
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for
> +   float.  */
> +extern TYPE ext[];
> +
> +void
> +store (TYPE a)
> +{
> +  ext[0] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store2 (TYPE a)
> +{
> +  ext[2] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store_large (TYPE a)
> +{
> +  ext[LARGE] = a;		/* No PCREL_OPT (store is prefixed).  */
> +}
> +
> +void
> +store_variable (TYPE a, unsigned long n)
> +{
> +  ext[n] = a;			/* No PCREL_OPT (store is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-si.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-si.c
> new file mode 100644
> index 00000000000..78dc8120efe
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-si.c
> @@ -0,0 +1,41 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	int
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for int.  */
> +extern TYPE ext[];
> +
> +void
> +store (TYPE a)
> +{
> +  ext[0] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store2 (TYPE a)
> +{
> +  ext[2] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store_large (TYPE a)
> +{
> +  ext[LARGE] = a;		/* No PCREL_OPT (store is prefixed).  */
> +}
> +
> +void
> +store_variable (TYPE a, unsigned long n)
> +{
> +  ext[n] = a;			/* No PCREL_OPT (store is indexed).  */
> +}
> +
> +void
> +store_double (double a)
> +{
> +  ext[0] = (TYPE) a;		/* No PCREL_OPT (STFIWX is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-vector.c b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-vector.c
> new file mode 100644
> index 00000000000..2c602eb3103
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pcrel-opt-st-vector.c
> @@ -0,0 +1,36 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target powerpc_pcrel } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
> +
> +#define TYPE	vector double
> +#define LARGE	0x20000
> +
> +/* Test whether we get the right number of PCREL_OPT optimizations for
> +   vector double.  */
> +extern TYPE ext[];
> +
> +void
> +store (TYPE a)
> +{
> +  ext[0] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store2 (TYPE a)
> +{
> +  ext[2] = a;			/* PCREL_OPT relocation.  */
> +}
> +
> +void
> +store_large (TYPE a)
> +{
> +  ext[LARGE] = a;		/* No PCREL_OPT (store is prefixed).  */
> +}
> +
> +void
> +store_variable (TYPE a, unsigned long n)
> +{
> +  ext[n] = a;			/* No PCREL_OPT (store is indexed).  */
> +}
> +
> +/* { dg-final { scan-assembler-times "R_PPC64_PCREL_OPT"  2 } } */
> -- 
> 2.18.4
> 



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