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[APX PPX] Support Intel APX PPX

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PPX stands for Push-Pop Acceleration. PUSH/PUSH2 and its corresponding POP
can be marked with a 1-bit hint to indicate that the POP reads the
value written by the PUSH from the stack. The processor tracks these marked
instructions internally and fast-forwards register data between
matching PUSH and POP instructions, without going through memory or
through the training loop of the Fast Store Forwarding Predictor (FSFP).
This feature can also be adopted to PUSH2/POP2.

For GCC, we emit explicit suffix 'p' (paired) to indicate the push/pop
pair are marked with PPX hint. To separate form original push/pop, we
add an UNSPEC on top of those PUSH/POP patterns.

In the first implementation we only emit them under prologue/epilogue
when saving/restoring callee-saved registers to make sure push/pop are
paired. So an extra flag was added to check if PPX insns can be emitted
for those register save/restore interfaces.

The PPX hint is purely a performance hint. If the 'p' suffix is not
emitted for paired push/pop, the PPX optimization will be disabled,
while program sematic will not be affected at all.

gcc/ChangeLog:

	* config/i386/i386-expand.h (gen_push): Add default bool
	parameter.
	(gen_pop): Likewise.
	* config/i386/i386-opts.h (enum apx_features): Add apx_ppx, add
	it to apx_all.
	* config/i386/i386.cc (ix86_emit_restore_reg_using_pop): Add
	ppx_p parameter for function declaration.
	(gen_push2): Add ppx_p parameter, emit push2p if ppx_p is true.
	(gen_push): Likewise.
	(ix86_emit_restore_reg_using_pop2): Likewise for pop2p.
	(ix86_emit_save_regs): Emit pushp/push2p under TARGET_APX_PPX.
	(ix86_emit_restore_reg_using_pop): Add ppx_p, emit popp insn
	and adjust cfi when ppx_p is ture.
	(ix86_emit_restore_reg_using_pop2): Add ppx_p and parse to its
	callee.
	(ix86_emit_restore_regs_using_pop2): Likewise.
	(ix86_expand_epilogue): Parse TARGET_APX_PPX to
	ix86_emit_restore_reg_using_pop.
	* config/i386/i386.h (TARGET_APX_PPX): New.
	* config/i386/i386.md (UNSPEC_APX_PPX): New unspec.
	(pushp_di): New define_insn.
	(popp_di): Likewise.
	(push2p_di): Likewise.
	(pop2p_di): Likewise.
	* config/i386/i386.opt: Add apx_ppx enum.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/apx-interrupt-1.c: Adjust option to restrict them
	under certain subfeatures.
	* gcc.target/i386/apx-push2pop2-1.c: Likewise.
	* gcc.target/i386/apx-push2pop2_force_drap-1.c: Likewise.
	* gcc.target/i386/apx-push2pop2_interrupt-1.c: Likewise.
	* gcc.target/i386/apx-ppx-1.c: New test.
This commit is contained in:
Hongyu Wang 2023-11-16 15:18:07 +08:00
parent f48244fad2
commit 7ad308bd4c
11 changed files with 107 additions and 36 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
gcc/config/i386/i386-expand.h
View file

@ -44,9 +44,9 @@ void ix86_emit_binop (enum rtx_code code, machine_mode mode, rtx dst, rtx src);
enum calling_abi ix86_function_abi (const_tree fndecl);
bool ix86_function_ms_hook_prologue (const_tree fn);
void warn_once_call_ms2sysv_xlogues (const char *feature);
rtx gen_push (rtx arg);
rtx gen_push (rtx arg, bool = false);
rtx gen_pushfl (void);
rtx gen_pop (rtx arg);
rtx gen_pop (rtx arg, bool = false);
rtx gen_popfl (void);
rtx ix86_expand_builtin (tree exp, rtx target, rtx subtarget,
machine_mode mode, int ignore);

3
gcc/config/i386/i386-opts.h
View file

@ -139,7 +139,8 @@ enum apx_features {
apx_egpr = 1 << 0,
apx_push2pop2 = 1 << 1,
apx_ndd = 1 << 2,
apx_all = apx_egpr | apx_push2pop2 | apx_ndd,
apx_ppx = 1 << 3,
apx_all = apx_egpr | apx_push2pop2 | apx_ndd | apx_ppx,
};
#endif

70
gcc/config/i386/i386.cc
View file

@ -105,7 +105,7 @@ along with GCC; see the file COPYING3. If not see
static rtx legitimize_dllimport_symbol (rtx, bool);
static rtx legitimize_pe_coff_extern_decl (rtx, bool);
static void ix86_print_operand_address_as (FILE *, rtx, addr_space_t, bool);
static void ix86_emit_restore_reg_using_pop (rtx);
static void ix86_emit_restore_reg_using_pop (rtx, bool = false);
#ifndef CHECK_STACK_LIMIT
@ -6448,7 +6448,7 @@ output_set_got (rtx dest, rtx label)
/* Generate an "push" pattern for input ARG. */
rtx
gen_push (rtx arg)
gen_push (rtx arg, bool ppx_p)
{
struct machine_function *m = cfun->machine;
@ -6459,10 +6459,10 @@ gen_push (rtx arg)
if (REG_P (arg) && GET_MODE (arg) != word_mode)
arg = gen_rtx_REG (word_mode, REGNO (arg));
return gen_rtx_SET (gen_rtx_MEM (word_mode,
gen_rtx_PRE_DEC (Pmode,
stack_pointer_rtx)),
arg);
rtx stack = gen_rtx_MEM (word_mode,
gen_rtx_PRE_DEC (Pmode,
stack_pointer_rtx));
return ppx_p ? gen_pushp_di (stack, arg) : gen_rtx_SET (stack, arg);
}
rtx
@ -6486,15 +6486,16 @@ gen_pushfl (void)
/* Generate an "pop" pattern for input ARG. */
rtx
gen_pop (rtx arg)
gen_pop (rtx arg, bool ppx_p)
{
if (REG_P (arg) && GET_MODE (arg) != word_mode)
arg = gen_rtx_REG (word_mode, REGNO (arg));
return gen_rtx_SET (arg,
gen_rtx_MEM (word_mode,
gen_rtx_POST_INC (Pmode,
stack_pointer_rtx)));
rtx stack = gen_rtx_MEM (word_mode,
gen_rtx_POST_INC (Pmode,
stack_pointer_rtx));
return ppx_p ? gen_popp_di (arg, stack) : gen_rtx_SET (arg, stack);
}
rtx
@ -6512,7 +6513,7 @@ gen_popfl (void)
/* Generate a "push2" pattern for input ARG. */
rtx
gen_push2 (rtx mem, rtx reg1, rtx reg2)
gen_push2 (rtx mem, rtx reg1, rtx reg2, bool ppx_p = false)
{
struct machine_function *m = cfun->machine;
const int offset = UNITS_PER_WORD * 2;
@ -6527,7 +6528,8 @@ gen_push2 (rtx mem, rtx reg1, rtx reg2)
if (REG_P (reg2) && GET_MODE (reg2) != word_mode)
reg2 = gen_rtx_REG (word_mode, REGNO (reg2));
return gen_push2_di (mem, reg1, reg2);
return ppx_p ? gen_push2p_di (mem, reg1, reg2):
gen_push2_di (mem, reg1, reg2);
}
/* Return >= 0 if there is an unused call-clobbered register available
@ -7369,7 +7371,8 @@ ix86_emit_save_regs (void)
for (regno = FIRST_PSEUDO_REGISTER - 1; regno >= 0; regno--)
if (GENERAL_REGNO_P (regno) && ix86_save_reg (regno, true, true))
{
insn = emit_insn (gen_push (gen_rtx_REG (word_mode, regno)));
insn = emit_insn (gen_push (gen_rtx_REG (word_mode, regno),
TARGET_APX_PPX));
RTX_FRAME_RELATED_P (insn) = 1;
}
}
@ -7399,7 +7402,8 @@ ix86_emit_save_regs (void)
gen_rtx_REG (word_mode,
regno_list[0]),
gen_rtx_REG (word_mode,
regno_list[1])));
regno_list[1]),
TARGET_APX_PPX));
RTX_FRAME_RELATED_P (insn) = 1;
rtx dwarf = gen_rtx_SEQUENCE (VOIDmode, rtvec_alloc (3));
@ -7431,7 +7435,8 @@ ix86_emit_save_regs (void)
}
else
{
insn = emit_insn (gen_push (gen_rtx_REG (word_mode, regno)));
insn = emit_insn (gen_push (gen_rtx_REG (word_mode, regno),
TARGET_APX_PPX));
RTX_FRAME_RELATED_P (insn) = 1;
aligned = true;
}
@ -7439,7 +7444,8 @@ ix86_emit_save_regs (void)
if (loaded_regnum == 1)
{
insn = emit_insn (gen_push (gen_rtx_REG (word_mode,
regno_list[0])));
regno_list[0]),
TARGET_APX_PPX));
RTX_FRAME_RELATED_P (insn) = 1;
}
}
@ -9268,13 +9274,13 @@ ix86_expand_prologue (void)
emit_insn (gen_prologue_use (stack_pointer_rtx));
}
/* Emit code to restore REG using a POP insn. */
/* Emit code to restore REG using a POP or POPP insn. */
static void
ix86_emit_restore_reg_using_pop (rtx reg)
ix86_emit_restore_reg_using_pop (rtx reg, bool ppx_p)
{
struct machine_function *m = cfun->machine;
rtx_insn *insn = emit_insn (gen_pop (reg));
rtx_insn *insn = emit_insn (gen_pop (reg, ppx_p));
ix86_add_cfa_restore_note (insn, reg, m->fs.sp_offset);
m->fs.sp_offset -= UNITS_PER_WORD;
@ -9328,14 +9334,19 @@ ix86_emit_restore_reg_using_pop (rtx reg)
/* Emit code to restore REG using a POP2 insn. */
static void
ix86_emit_restore_reg_using_pop2 (rtx reg1, rtx reg2)
ix86_emit_restore_reg_using_pop2 (rtx reg1, rtx reg2, bool ppx_p = false)
{
struct machine_function *m = cfun->machine;
const int offset = UNITS_PER_WORD * 2;
rtx_insn *insn;
rtx mem = gen_rtx_MEM (TImode, gen_rtx_POST_INC (Pmode,
stack_pointer_rtx));
rtx_insn *insn = emit_insn (gen_pop2_di (reg1, mem, reg2));
if (ppx_p)
insn = emit_insn (gen_pop2p_di (reg1, mem, reg2));
else
insn = emit_insn (gen_pop2_di (reg1, mem, reg2));
RTX_FRAME_RELATED_P (insn) = 1;
@ -9397,13 +9408,13 @@ ix86_emit_restore_reg_using_pop2 (rtx reg1, rtx reg2)
/* Emit code to restore saved registers using POP insns. */
static void
ix86_emit_restore_regs_using_pop (void)
ix86_emit_restore_regs_using_pop (bool ppx_p)
{
unsigned int regno;
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (GENERAL_REGNO_P (regno) && ix86_save_reg (regno, false, true))
ix86_emit_restore_reg_using_pop (gen_rtx_REG (word_mode, regno));
ix86_emit_restore_reg_using_pop (gen_rtx_REG (word_mode, regno), ppx_p);
}
/* Emit code to restore saved registers using POP2 insns. */
@ -9432,20 +9443,23 @@ ix86_emit_restore_regs_using_pop2 (void)
ix86_emit_restore_reg_using_pop2 (gen_rtx_REG (word_mode,
regno_list[0]),
gen_rtx_REG (word_mode,
regno_list[1]));
regno_list[1]),
TARGET_APX_PPX);
loaded_regnum = 0;
regno_list[0] = regno_list[1] = -1;
}
}
else
{
ix86_emit_restore_reg_using_pop (gen_rtx_REG (word_mode, regno));
ix86_emit_restore_reg_using_pop (gen_rtx_REG (word_mode, regno),
TARGET_APX_PPX);
aligned = true;
}
}
if (loaded_regnum == 1)
ix86_emit_restore_reg_using_pop (gen_rtx_REG (word_mode, regno_list[0]));
ix86_emit_restore_reg_using_pop (gen_rtx_REG (word_mode, regno_list[0]),
TARGET_APX_PPX);
}
/* Emit code and notes for the LEAVE instruction. If insn is non-null,
@ -9990,7 +10004,7 @@ ix86_expand_epilogue (int style)
if (TARGET_APX_PUSH2POP2 && m->func_type == TYPE_NORMAL)
ix86_emit_restore_regs_using_pop2 ();
else
ix86_emit_restore_regs_using_pop ();
ix86_emit_restore_regs_using_pop (TARGET_APX_PPX);
}
/* If we used a stack pointer and haven't already got rid of it,

1
gcc/config/i386/i386.h
View file

@ -54,6 +54,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#define TARGET_APX_EGPR (ix86_apx_features & apx_egpr)
#define TARGET_APX_PUSH2POP2 (ix86_apx_features & apx_push2pop2)
#define TARGET_APX_NDD (ix86_apx_features & apx_ndd)
#define TARGET_APX_PPX (ix86_apx_features & apx_ppx)
#include "config/vxworks-dummy.h"

45
gcc/config/i386/i386.md
View file

@ -210,10 +210,13 @@
;; For insn_callee_abi:
UNSPEC_CALLEE_ABI
;; For PUSH2/POP2 support
;; For APX PUSH2/POP2 support
UNSPEC_APXPUSH2
UNSPEC_APXPOP2_LOW
UNSPEC_APXPOP2_HIGH
;; For APX PPX support
UNSPEC_APX_PPX
])
(define_c_enum "unspecv" [
@ -3785,6 +3788,46 @@
[(set_attr "mode" "TI")
(set_attr "prefix" "evex")])
(define_insn "pushp_di"
[(set (match_operand:DI 0 "push_operand" "=<")
(match_operand:DI 1 "register_operand" "r"))
(unspec:DI [(const_int 0)] UNSPEC_APX_PPX)]
"TARGET_64BIT"
"pushp\t%1"
[(set_attr "mode" "DI")])
(define_insn "popp_di"
[(set (match_operand:DI 0 "register_operand" "=r")
(match_operand:DI 1 "pop_operand" ">"))
(unspec:DI [(const_int 0)] UNSPEC_APX_PPX)]
"TARGET_APX_PPX"
"popp\t%0"
[(set_attr "mode" "DI")])
(define_insn "push2p_di"
[(set (match_operand:TI 0 "push_operand" "=<")
(unspec:TI [(match_operand:DI 1 "register_operand" "r")
(match_operand:DI 2 "register_operand" "r")]
UNSPEC_APXPUSH2))
(unspec:DI [(const_int 0)] UNSPEC_APX_PPX)]
"TARGET_APX_PUSH2POP2 && TARGET_APX_PPX"
"push2p\t%1, %2"
[(set_attr "mode" "TI")
(set_attr "type" "multi")
(set_attr "prefix" "evex")])
(define_insn "pop2p_di"
[(parallel [(set (match_operand:DI 0 "register_operand" "=r")
(unspec:DI [(match_operand:TI 1 "pop_operand" ">")]
UNSPEC_APXPOP2_LOW))
(set (match_operand:DI 2 "register_operand" "=r")
(unspec:DI [(const_int 0)] UNSPEC_APXPOP2_HIGH))
(unspec:DI [(const_int 0)] UNSPEC_APX_PPX)])]
"TARGET_APX_PUSH2POP2 && TARGET_APX_PPX"
"pop2p\t%0, %2"
[(set_attr "mode" "TI")
(set_attr "prefix" "evex")])
(define_insn "*pushsf_rex64"
[(set (match_operand:SF 0 "push_operand" "=X,X,X")
(match_operand:SF 1 "nonmemory_no_elim_operand" "f,rF,v"))]

3
gcc/config/i386/i386.opt
View file

@ -1348,6 +1348,9 @@ Enum(apx_features) String(push2pop2) Value(apx_push2pop2) Set(3)
EnumValue
Enum(apx_features) String(ndd) Value(apx_ndd) Set(4)
EnumValue
Enum(apx_features) String(ppx) Value(apx_ppx) Set(5)
EnumValue
Enum(apx_features) String(all) Value(apx_all) Set(1)

2
gcc/testsuite/gcc.target/i386/apx-interrupt-1.c
View file

@ -1,5 +1,5 @@
/* { dg-do compile { target { ! ia32 } } } */
/* { dg-options "-mapxf -m64 -O2 -mgeneral-regs-only -mno-cld -mno-push-args -maccumulate-outgoing-args" } */
/* { dg-options "-mapx-features=egpr -m64 -O2 -mgeneral-regs-only -mno-cld -mno-push-args -maccumulate-outgoing-args" } */
/* { dg-skip-if "does not emit .cfi_xxx" "*-*-darwin*" } */
extern void foo (void *) __attribute__ ((interrupt));

9
gcc/testsuite/gcc.target/i386/apx-ppx-1.c Normal file
View file

@ -0,0 +1,9 @@
/* { dg-do compile { target { ! ia32 } } } */
/* { dg-options "-O2 -mapx-features=egpr,push2pop2,ppx" } */
#include "apx-push2pop2-1.c"
/* { dg-final { scan-assembler "pushp" } } */
/* { dg-final { scan-assembler "popp" } } */
/* { dg-final { scan-assembler "push2p" } } */
/* { dg-final { scan-assembler "pop2p" } } */

2
gcc/testsuite/gcc.target/i386/apx-push2pop2-1.c
View file

@ -1,5 +1,5 @@
/* { dg-do compile { target { ! ia32 } } } */
/* { dg-options "-O2 -mapxf" } */
/* { dg-options "-O2 -mapx-features=push2pop2" } */
/* { dg-skip-if "does not emit .cfi_xxx" "*-*-darwin*" } */
extern int bar (int);

2
gcc/testsuite/gcc.target/i386/apx-push2pop2_force_drap-1.c
View file

@ -1,5 +1,5 @@
/* { dg-do compile { target { ! ia32 } } } */
/* { dg-options "-O2 -mapxf -mforce-drap" } */
/* { dg-options "-O2 -mapx-features=push2pop2 -mforce-drap" } */
/* { dg-skip-if "does not emit .cfi_xxx" "*-*-darwin*" } */
#include "apx-push2pop2-1.c"

2
gcc/testsuite/gcc.target/i386/apx-push2pop2_interrupt-1.c
View file

@ -1,5 +1,5 @@
/* { dg-do compile { target { ! ia32 } } } */
/* { dg-options "-O2 -mapxf -mgeneral-regs-only -mno-cld -mno-push-args -maccumulate-outgoing-args" } */
/* { dg-options "-O2 -mapx-features=egpr,push2pop2 -mgeneral-regs-only -mno-cld -mno-push-args -maccumulate-outgoing-args" } */
extern void foo (void *) __attribute__ ((interrupt));