On Tue, Aug 26, 2025 at 10:24 PM Hongtao Liu <crazy...@gmail.com> wrote:
>
> On Wed, Aug 27, 2025 at 6:32 AM H.J. Lu <hjl.to...@gmail.com> wrote:
> >
> > Source operands of 2 *tls_dynamic_gnu2_call_64_di patterns in
> >
> > (insn 10 9 11 3 (set (reg:DI 100)
> > (unspec:DI [
> > (symbol_ref:DI ("caml_state") [flags 0x10] <var_decl
> > 0x7fe10e1d9e40 caml_state>)
> > ] UNSPEC_TLSDESC)) "x.c":7:16 1674 {*tls_dynamic_gnu2_lea_64_di}
> > (nil))
> > (insn 11 10 12 3 (parallel [
> > (set (reg:DI 99)
> > (unspec:DI [
> > (symbol_ref:DI ("caml_state") [flags 0x10]
> > <var_decl 0x7fe10e1d9e40 caml_state>)
> > (reg:DI 100)
> > (reg/f:DI 7 sp)
> > ] UNSPEC_TLSDESC))
> > (clobber (reg:CC 17 flags))
> > ]) "x.c":7:16 1676 {*tls_dynamic_gnu2_call_64_di}
> > (expr_list:REG_DEAD (reg:DI 100)
> > (expr_list:REG_UNUSED (reg:CC 17 flags)
> > (nil))))
> >
> > and
> >
> > (insn 19 17 20 4 (set (reg:DI 104)
> > (unspec:DI [
> > (symbol_ref:DI ("caml_state") [flags 0x10] <var_decl
> > 0x7fe10e1d9e40 caml_state>)
> > ] UNSPEC_TLSDESC)) "x.c":6:10 discrim 1 1674
> > {*tls_dynamic_gnu2_lea_64_di}
> > (nil))
> > (insn 20 19 21 4 (parallel [
> > (set (reg:DI 103)
> > (unspec:DI [
> > (symbol_ref:DI ("caml_state") [flags 0x10]
> > <var_decl 0x7fe10e1d9e40 caml_state>)
> > (reg:DI 104)
> > (reg/f:DI 7 sp)
> > ] UNSPEC_TLSDESC))
> > (clobber (reg:CC 17 flags))
> > ]) "x.c":6:10 discrim 1 1676 {*tls_dynamic_gnu2_call_64_di}
> > (expr_list:REG_DEAD (reg:DI 104)
> > (expr_list:REG_UNUSED (reg:CC 17 flags)
> > (nil))))
> >
> > are the same even though rtx_equal_p returns false since (reg:DI 100)
> > and (reg:DI 104) are set from the same symbol. Add x86_cse_rtx_equal_p
> > to compare source operands of *tls_dynamic_gnu2_call_64_di patterns and
> > return true if only source operands differ and they are set from the
> > same symbol.
> >
> > gcc/
> >
> > * config/i386/i386-features.cc
> > (pass_x86_cse::x86_cse_rtx_equal_p): New.
> > (pass_x86_cse::tls_set_insn_from_symbol): Likewise.
> > (pass_x86_cse::candidate_gnu2_tls_p): Call
> > tls_set_insn_from_symbol.
> > (pass_x86_cse::x86_cse): Call x86_cse_rtx_equal_p, instead of
> > rtx_equal_p, to compare 2 values.
> >
> > gcc/testsuite/
> >
> > * gcc.target/i386/pr121668-1b.c: New test.
> >
> > Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
> > ---
> > gcc/config/i386/i386-features.cc | 116 +++++++++++++++-----
> > gcc/testsuite/gcc.target/i386/pr121668-1b.c | 6 +
> > 2 files changed, 95 insertions(+), 27 deletions(-)
> > create mode 100644 gcc/testsuite/gcc.target/i386/pr121668-1b.c
> >
> > diff --git a/gcc/config/i386/i386-features.cc
> > b/gcc/config/i386/i386-features.cc
> > index 93e20947edf..ce77e91c120 100644
> > --- a/gcc/config/i386/i386-features.cc
> > +++ b/gcc/config/i386/i386-features.cc
> > @@ -4168,8 +4168,95 @@ private:
> > bool candidate_gnu_tls_p (rtx_insn *, attr_tls64);
> > bool candidate_gnu2_tls_p (rtx, attr_tls64);
> > bool candidate_vector_p (rtx);
> > + bool x86_cse_rtx_equal_p (const_rtx, const_rtx);
> > + rtx_insn *tls_set_insn_from_symbol (const_rtx, rtx *);
> > }; // class pass_x86_cse
> >
> > +/* Return true if X and Y are equal. */
> > +
> > +bool
> > +pass_x86_cse::x86_cse_rtx_equal_p (const_rtx x, const_rtx y)
> > +{
> > + if (kind == X86_CSE_TLSDESC
> > + && GET_CODE (x) == UNSPEC
> > + && XINT (x, 1) == UNSPEC_TLSDESC
> > + && SYMBOL_REF_P (XVECEXP (x, 0, 0)))
> > + {
> > + /* Compare
> > +
> > + (unspec:DI [
> > + (symbol_ref:DI ("caml_state") [flags 0x10] <var_decl
> > 0x7fffe99d9e40 caml_state>)
> > + (reg:DI 100)
> > + (reg/f:DI 7 sp)
> > + ] UNSPEC_TLSDESC)
> > +
> > + against
> > +
> > + (unspec:DI [
> > + (symbol_ref:DI ("caml_state") [flags 0x10] <var_decl
> > 0x7fffe99d9e40 caml_state>)
> > + (reg:DI 104)
> > + (reg/f:DI 7 sp)
> > + ] UNSPEC_TLSDESC)
> > +
> > + If (reg:DI 100) and (reg:DI 104) are defined from the same source,
> > + they are equal. */
> > +
> > + if (GET_CODE (y) != UNSPEC
> > + || XINT (y, 1) != UNSPEC_TLSDESC
> > + || !SYMBOL_REF_P (XVECEXP (y, 0, 0))
> > + || !rtx_equal_p (XVECEXP (x, 0, 0), XVECEXP (y, 0, 0)))
> > + return false;
> > +
> > + x = XVECEXP (x, 0, 1);
> > + y = XVECEXP (y, 0, 1);
> > + if (rtx_equal_p (x, y))
> > + return true;
> > +
> > + rtx tls_symbol = nullptr;
> > + return (tls_set_insn_from_symbol (x, &tls_symbol)
> > + && tls_symbol
> > + && tls_set_insn_from_symbol (y, &tls_symbol));
> > + }
> > +
> > + return rtx_equal_p (x, y);
> > +}
> > +
> > +/* Return the instruction which sets REG from one symbol and store the
> > + symbol in *TLS_SYMBOL_P if *TLS_SYMBOL_P is nullptr. */
> > +
> > +rtx_insn *
> > +pass_x86_cse::tls_set_insn_from_symbol (const_rtx reg, rtx *tls_symol_p)
> > +{
> > + rtx_insn *set_insn = nullptr;
> > + rtx tls_symbol = *tls_symol_p;
> > + for (df_ref ref = DF_REG_DEF_CHAIN (REGNO (reg));
> > + ref;
> > + ref = DF_REF_NEXT_REG (ref))
> > + {
> > + if (DF_REF_IS_ARTIFICIAL (ref))
> > + return nullptr;
> > +
> > + set_insn = DF_REF_INSN (ref);
> > + if (get_attr_tls64 (set_insn) != TLS64_LEA)
> > + return nullptr;
> > +
> > + rtx tls_set = PATTERN (set_insn);
> > + rtx tls_src = XVECEXP (SET_SRC (tls_set), 0, 0);
> > + if (tls_symbol == nullptr)
> > + {
> > + if (!SYMBOL_REF_P (tls_src))
> > + return nullptr;
> > +
> > + tls_symbol = tls_src;
> > + *tls_symol_p = tls_src;
> > + }
> > + else if (!rtx_equal_p (tls_symbol, tls_src))
> > + return nullptr;
> > + }
> > +
> > + return set_insn;
> > +}
> > +
> > /* Return true and output def_insn, val, mode, scalar_mode and kind if
> > INSN is UNSPEC_TLS_GD or UNSPEC_TLS_LD_BASE. */
> >
> > @@ -4283,32 +4370,7 @@ pass_x86_cse::candidate_gnu2_tls_p (rtx set,
> > attr_tls64 tls64)
> >
> > */
> >
> > - df_ref ref;
> > - rtx_insn *set_insn = nullptr;
> > - for (ref = DF_REG_DEF_CHAIN (REGNO (src));
> > - ref;
> > - ref = DF_REF_NEXT_REG (ref))
> > - {
> > - if (DF_REF_IS_ARTIFICIAL (ref))
> > - break;
> > -
> > - set_insn = DF_REF_INSN (ref);
> > - tls64 = get_attr_tls64 (set_insn);
> > - if (tls64 != TLS64_LEA)
> > - {
> > - set_insn = nullptr;
> > - break;
> > - }
> > -
> > - rtx tls_set = PATTERN (set_insn);
> > - rtx tls_src = XVECEXP (SET_SRC (tls_set), 0, 0);
> > - if (!rtx_equal_p (tls_symbol, tls_src))
> > - {
> > - set_insn = nullptr;
> > - break;
> > - }
> > - }
> > -
> > + rtx_insn *set_insn = tls_set_insn_from_symbol (src, &tls_symbol);
> > if (!set_insn)
> > return false;
> >
> > @@ -4436,7 +4498,7 @@ pass_x86_cse::x86_cse (void)
> > /* Non all 0s/1s vector load must be in the same
> > basic block if it is in a recursive call. */
> > || !recursive_call_p)
> > - && rtx_equal_p (load->val, val))
> > + && x86_cse_rtx_equal_p (load->val, val))
> Can we just record val as tls_symbol in candidate_gnu2_tls_p, and
> adjust code in ix86_place_single_tls_call?
I added tlsdesc_val and record val as tls_symbol in the v2 patch.
> > {
> > /* Record instruction. */
> > bitmap_set_bit (load->insns, INSN_UID (insn));
> > diff --git a/gcc/testsuite/gcc.target/i386/pr121668-1b.c
> > b/gcc/testsuite/gcc.target/i386/pr121668-1b.c
> > new file mode 100644
> > index 00000000000..54a277506f8
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr121668-1b.c
> > @@ -0,0 +1,6 @@
> > +/* { dg-do compile { target *-*-linux* } } */
> > +/* { dg-options "-Og -g -fpic -fplt -mtls-dialect=gnu2" } */
> > +
> > +#include "pr121668-1a.c"
> > +
> > +/* { dg-final { scan-assembler-times "call\[
> > \t\]\\*caml_state@TLSCALL\\(%(?:r|e)ax\\)" 1 { target { ! ia32 } } } } */
> > --
> > 2.51.0
> >
>
>
> --
> BR,
> Hongtao
--
H.J.
