> -----Original Message-----
> From: H.J. Lu <hjl.to...@gmail.com>
> Sent: Saturday, August 30, 2025 7:49 AM
> To: gcc-patches@gcc.gnu.org
> Cc: Liu, Hongtao <hongtao....@intel.com>; ubiz...@gmail.com
> Subject: [PATCH] x86-64: Use UNSPEC_DTPOFF to check source operand in
> TLS64_COMBINE
>
> Since the first operand of PLUS in the source of TLS64_COMBINE pattern:
>
> (set (reg/f:DI 128)
> (plus:DI (unspec:DI [
> (symbol_ref:DI ("_TLS_MODULE_BASE_") [flags 0x10])
> (reg:DI 126)
> (reg/f:DI 7 sp)
> ] UNSPEC_TLSDESC)
> (const:DI (unspec:DI [
> (symbol_ref:DI ("bfd_error") [flags 0x1a] <var_decl
> 0x7fffe99d6e40
> bfd_error>)
> ] UNSPEC_DTPOFF))))
>
> is unused, use the second operand of PLUS:
Yes, exactly, it will be splitted according to the second operand.
>
> (const:DI (unspec:DI [
> (symbol_ref:DI ("bfd_error") [flags 0x1a] <var_decl 0x7fffe99d6e40
> bfd_error>)
> ] UNSPEC_DTPOFF))
>
> to check if 2 TLS_COMBINE patterns have the same source.
LGTM.
>
> gcc/
>
> PR target/121725
> * config/i386/i386-features.cc
> (pass_x86_cse::candidate_gnu2_tls_p): Use the UNSPEC_DTPOFF
> operand to check source operand in TLS64_COMBINE pattern.
>
> gcc/testsuite/
>
> PR target/121725
> * gcc.target/i386/pr121725-1a.c: New test.
> * gcc.target/i386/pr121725-1b.c: Likewise.
>
> Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
> ---
> gcc/config/i386/i386-features.cc | 32 +++++-----------
> gcc/testsuite/gcc.target/i386/pr121725-1a.c | 41
> +++++++++++++++++++++ gcc/testsuite/gcc.target/i386/pr121725-1b.c | 6
> +++
> 3 files changed, 57 insertions(+), 22 deletions(-) create mode 100644
> gcc/testsuite/gcc.target/i386/pr121725-1a.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr121725-1b.c
>
> diff --git a/gcc/config/i386/i386-features.cc b/gcc/config/i386/i386-
> features.cc
> index 5440a02c442..0608dd2f9ac 100644
> --- a/gcc/config/i386/i386-features.cc
> +++ b/gcc/config/i386/i386-features.cc
> @@ -4291,34 +4291,22 @@ pass_x86_cse::candidate_gnu2_tls_p (rtx set,
> attr_tls64 tls64)
> */
>
> scalar_mode = mode = GET_MODE (src);
> - rtx src0 = XEXP (src, 0);
> - tls_symbol = XVECEXP (src0, 0, 0);
> - rtx src1 = XVECEXP (src0, 0, 1);
> - if (REG_P (src1))
> - {
> - set_insn = tls_set_insn_from_symbol (src1, tls_symbol);
> - gcc_assert (set_insn);
> - }
> - else
> - {
> - set_insn = nullptr;
> - gcc_assert (GET_CODE (src1) == UNSPEC
> - && XINT (src1, 1) == UNSPEC_TLSDESC
> - && SYMBOL_REF_P (XVECEXP (src1, 0, 0))
> - && rtx_equal_p (XVECEXP (src1, 0, 0), tls_symbol));
> - }
>
> - /* Use TLS_SYMBOL and
> + /* Since the first operand of PLUS in the source TLS_COMBINE
> + pattern is unused, use the second operand of PLUS:
>
> (const:DI (unspec:DI [
> (symbol_ref:DI ("e") [flags 0x1a])
> ] UNSPEC_DTPOFF))
>
> - as VAL to check if 2 patterns have the same source. */
> -
> - rtvec vec = gen_rtvec (2, tls_symbol, XEXP (src, 1));
> - val = gen_rtx_UNSPEC (mode, vec, UNSPEC_TLSDESC);
> - def_insn = set_insn;
> + as VAL to check if 2 TLS_COMBINE patterns have the same
> + source. */
> + val = XEXP (src, 1);
> + gcc_assert (GET_CODE (val) == CONST
> + && GET_CODE (XEXP (val, 0)) == UNSPEC
> + && XINT (XEXP (val, 0), 1) == UNSPEC_DTPOFF
> + && SYMBOL_REF_P (XVECEXP (XEXP (val, 0), 0, 0)));
> + def_insn = nullptr;
> return true;
> }
>
> diff --git a/gcc/testsuite/gcc.target/i386/pr121725-1a.c
> b/gcc/testsuite/gcc.target/i386/pr121725-1a.c
> new file mode 100644
> index 00000000000..d0a498cace9
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr121725-1a.c
> @@ -0,0 +1,41 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O3 -fpic -fplt -mtls-dialect=gnu" } */
> +
> +typedef enum
> +{
> + bfd_error_invalid_error_code
> +} bfd_error_type;
> +static thread_local bfd_error_type bfd_error; extern int sections;
> +extern void *bfd_alloc_ret; extern int bfd_alloc___o; extern long
> +bfd_alloc_size;
> +
> +extern void _objalloc_alloc (int *, long);
> +
> +bfd_error_type
> +bfd_get_error ()
> +{
> + return bfd_error;
> +}
> +
> +bool
> +s7_bfd_score_elf_late_size_sections ()
> +{
> + for (; sections;)
> + {
> + if (bfd_alloc_size)
> + {
> + bfd_error_type error_tag;
> + bfd_error = error_tag;
> + }
> + _objalloc_alloc (&bfd_alloc___o, 0);
> + if (bfd_alloc_ret)
> + {
> + bfd_error_type error_tag;
> + bfd_error = error_tag;
> + }
> + }
> +}
> +
> +/* { dg-final { scan-assembler-times "call\[ \t\]__tls_get_addr@PLT" 2
> +{ target { ! ia32 } } } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr121725-1b.c
> b/gcc/testsuite/gcc.target/i386/pr121725-1b.c
> new file mode 100644
> index 00000000000..0b97a8a4cb6
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr121725-1b.c
> @@ -0,0 +1,6 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O3 -fpic -fplt -mtls-dialect=gnu2" } */
> +
> +#include "pr121725-1a.c"
> +
> +/* { dg-final { scan-assembler-times "call\[
> +\t\]\\*bfd_error@TLSCALL\\(%(?:r|e)ax\\)" 2 { target { ! ia32 } } } }
> +*/
> --
> 2.51.0
