x86-64: Remove redundant TLS calls

For TLS calls:

1. UNSPEC_TLS_GD:

  (parallel [
    (set (reg:DI 0 ax)
   	 (call:DI (mem:QI (symbol_ref:DI ("__tls_get_addr")))
		  (const_int 0 [0])))
    (unspec:DI [(symbol_ref:DI ("e") [flags 0x50])
                (reg/f:DI 7 sp)] UNSPEC_TLS_GD)
    (clobber (reg:DI 5 di))])

2. UNSPEC_TLS_LD_BASE:

  (parallel [
    (set (reg:DI 0 ax)
	 (call:DI (mem:QI (symbol_ref:DI ("__tls_get_addr")))
		  (const_int 0 [0])))
    (unspec:DI [(reg/f:DI 7 sp)] UNSPEC_TLS_LD_BASE)])

3. UNSPEC_TLSDESC:

  (parallel [
     (set (reg/f:DI 104)
	   (plus:DI (unspec:DI [
		       (symbol_ref:DI ("_TLS_MODULE_BASE_") [flags 0x10])
                       (reg:DI 114)
                       (reg/f:DI 7 sp)] UNSPEC_TLSDESC)
                    (const:DI (unspec:DI [
				 (symbol_ref:DI ("e") [flags 0x1a])
			      ] UNSPEC_DTPOFF))))
     (clobber (reg:CC 17 flags))])

  (parallel [
    (set (reg:DI 101)
	 (unspec:DI [(symbol_ref:DI ("e") [flags 0x50])
                     (reg:DI 112)
                     (reg/f:DI 7 sp)] UNSPEC_TLSDESC))
    (clobber (reg:CC 17 flags))])

they return the same value for the same input value.  But multiple calls
with the same input value may be generated for simple programs like:

void a(long *);
int b(void);
void c(void);
static __thread long e;
long
d(void)
{
  a(&e);
  if (b())
    c();
  return e;
}

When compiled with -O2 -fPIC -mtls-dialect=gnu2, the following codes are
generated:

	.type	d, @function
d:
.LFB0:
	.cfi_startproc
	pushq	%rbx
	.cfi_def_cfa_offset 16
	.cfi_offset 3, -16
	leaq	e@TLSDESC(%rip), %rbx
	movq	%rbx, %rax
	call	*e@TLSCALL(%rax)
	addq	%fs:0, %rax
	movq	%rax, %rdi
	call	a@PLT
	call	b@PLT
	testl	%eax, %eax
	jne	.L8
	movq	%rbx, %rax
	call	*e@TLSCALL(%rax)
	popq	%rbx
	.cfi_remember_state
	.cfi_def_cfa_offset 8
	movq	%fs:(%rax), %rax
	ret
	.p2align 4,,10
	.p2align 3
.L8:
	.cfi_restore_state
	call	c@PLT
	movq	%rbx, %rax
	call	*e@TLSCALL(%rax)
	popq	%rbx
	.cfi_def_cfa_offset 8
	movq	%fs:(%rax), %rax
	ret
	.cfi_endproc

There are 3 "call *e@TLSCALL(%rax)".  They all return the same value.
Rename the remove_redundant_vector pass to the x86_cse pass, for 64bit,
extend it to also remove redundant TLS calls to generate:

d:
.LFB0:
	.cfi_startproc
	pushq	%rbx
	.cfi_def_cfa_offset 16
	.cfi_offset 3, -16
	leaq	e@TLSDESC(%rip), %rax
	movq	%fs:0, %rdi
	call	*e@TLSCALL(%rax)
	addq	%rax, %rdi
	movq	%rax, %rbx
	call	a@PLT
	call	b@PLT
	testl	%eax, %eax
	jne	.L8
	movq	%fs:(%rbx), %rax
	popq	%rbx
	.cfi_remember_state
	.cfi_def_cfa_offset 8
	ret
	.p2align 4,,10
	.p2align 3
.L8:
	.cfi_restore_state
	call	c@PLT
	movq	%fs:(%rbx), %rax
	popq	%rbx
	.cfi_def_cfa_offset 8
	ret
	.cfi_endproc

with only one "call *e@TLSCALL(%rax)".  This reduces the number of
__tls_get_addr calls in libgcc.a by 72%:

__tls_get_addr calls     before         after
libgcc.a                 868            243

gcc/

	PR target/81501
	* config/i386/i386-features.cc (x86_cse_kind): Add X86_CSE_TLS_GD,
	X86_CSE_TLS_LD_BASE and X86_CSE_TLSDESC.
	(redundant_load): Renamed to ...
	(redundant_pattern): This.
	(ix86_place_single_vector_set): Replace redundant_load with
	redundant_pattern.
	(replace_tls_call): New.
	(ix86_place_single_tls_call): Likewise.
	(pass_remove_redundant_vector_load): Renamed to ...
	(pass_x86_cse): This.  Add val, def_insn, mode, scalar_mode, kind,
	x86_cse, candidate_gnu_tls_p, candidate_gnu2_tls_p and
	candidate_vector_p.
	(pass_x86_cse::candidate_gnu_tls_p): New.
	(pass_x86_cse::candidate_gnu2_tls_p): Likewise.
	(pass_x86_cse::candidate_vector_p): Likewise.
	(remove_redundant_vector_load): Renamed to ...
	(pass_x86_cse::x86_cse): This.  Extend to remove redundant TLS
	calls.
	(make_pass_remove_redundant_vector_load): Renamed to ...
	(make_pass_x86_cse): This.
	* config/i386/i386-passes.def: Replace
	pass_remove_redundant_vector_load with pass_x86_cse.
	* config/i386/i386-protos.h (ix86_tls_get_addr): New.
	(make_pass_remove_redundant_vector_load): Renamed to ...
	(make_pass_x86_cse): This.
	* config/i386/i386.cc (ix86_tls_get_addr): Remove static.
	* config/i386/i386.h (machine_function): Add
	tls_descriptor_call_multiple_p.
	* config/i386/i386.md (tls64): New attribute.
	(@tls_global_dynamic_64_<mode>): Set tls_descriptor_call_multiple_p.
	(@tls_local_dynamic_base_64_<mode>): Likewise.
	(@tls_dynamic_gnu2_64_<mode>): Likewise.
	(*tls_global_dynamic_64_<mode>): Set tls64 attribute to gd.
	(*tls_local_dynamic_base_64_<mode>): Set tls64 attribute to ld_base.
	(*tls_dynamic_gnu2_lea_64_<mode>): Set tls64 attribute to lea.
	(*tls_dynamic_gnu2_call_64_<mode>): Set tls64 attribute to call.
	(*tls_dynamic_gnu2_combine_64_<mode>): Set tls64 attribute to
	combine.

gcc/testsuite/

	PR target/81501
	* g++.target/i386/pr81501-1.C: New test.
	* gcc.target/i386/pr81501-1a.c: Likewise.
	* gcc.target/i386/pr81501-1b.c: Likewise.
	* gcc.target/i386/pr81501-2a.c: Likewise.
	* gcc.target/i386/pr81501-2b.c: Likewise.
	* gcc.target/i386/pr81501-3.c: Likewise.
	* gcc.target/i386/pr81501-4a.c: Likewise.
	* gcc.target/i386/pr81501-4b.c: Likewise.
	* gcc.target/i386/pr81501-5.c: Likewise.
	* gcc.target/i386/pr81501-6a.c: Likewise.
	* gcc.target/i386/pr81501-6b.c: Likewise.
	* gcc.target/i386/pr81501-7.c: Likewise.
	* gcc.target/i386/pr81501-8a.c: Likewise.
	* gcc.target/i386/pr81501-8b.c: Likewise.
	* gcc.target/i386/pr81501-9a.c: Likewise.
	* gcc.target/i386/pr81501-9b.c: Likewise.
	* gcc.target/i386/pr81501-10a.c: Likewise.
	* gcc.target/i386/pr81501-10b.c: Likewise.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>

0 files changed, 0 insertions, 0 deletions