Oh, I just found that asm ("%p0" :: "i"(addr)); also works on
-mcmodel=large in this case, please ignore this patch. Thanks.
Uros Bizjak via Gcc-patches <gcc-patches@gcc.gnu.org> 于2022年5月18日周三 17:46写道：
>
> On Wed, May 18, 2022 at 9:32 AM Hongyu Wang <hongyu.w...@intel.com> wrote:
> >
> > Hi,
> >
> > This patch adds a constraint "Ws" to allow absolute symbolic address for
> > either
> > function or variable. This also works under -mcmodel=large.
> >
> > Bootstrapped/regtested on x86_64-pc-linux-gnu{-m32,}
> >
> > Ok for master?
>
> Maybe you should use:
>
> asm ("%p0" :: "X"(addr));
> asm ("%p0" :: "X"(&var));
>
> instead.
>
> Uros.
>
> > gcc/ChangeLog:
> >
> > PR target/105576
> > * config/i386/constraints.md (Ws): New constraint.
> > * config/i386/i386-protos.h (ix86_symbolic_address_p):
> > New proto type.
> > * config/i386/i386.cc (ix86_symbolic_address_p):
> > New function to ensure a rtx is a symbolic address.
> >
> > gcc/testsuite/ChangeLog:
> >
> > PR target/105576
> > * gcc.target/i386/pr105576.c: New test.
> > ---
> > gcc/config/i386/constraints.md | 4 ++++
> > gcc/config/i386/i386-protos.h | 1 +
> > gcc/config/i386/i386.cc | 7 +++++++
> > gcc/testsuite/gcc.target/i386/pr105576.c | 11 +++++++++++
> > 4 files changed, 23 insertions(+)
> > create mode 100644 gcc/testsuite/gcc.target/i386/pr105576.c
> >
> > diff --git a/gcc/config/i386/constraints.md b/gcc/config/i386/constraints.md
> > index 7361687632f..ec0702be368 100644
> > --- a/gcc/config/i386/constraints.md
> > +++ b/gcc/config/i386/constraints.md
> > @@ -348,6 +348,10 @@ (define_constraint "Z"
> > instructions)."
> > (match_operand 0 "x86_64_zext_immediate_operand"))
> >
> > +(define_constraint "Ws"
> > + "A constraint that matches an absolute symbolic address."
> > + (match_test "ix86_symbolic_address_p (op)"))
> > +
> > ;; T prefix is used for different address constraints
> > ;; v - VSIB address
> > ;; s - address with no segment register
> > diff --git a/gcc/config/i386/i386-protos.h b/gcc/config/i386/i386-protos.h
> > index 3596ce81ecf..2b8d063850f 100644
> > --- a/gcc/config/i386/i386-protos.h
> > +++ b/gcc/config/i386/i386-protos.h
> > @@ -337,6 +337,7 @@ extern void x86_output_aligned_bss (FILE *, tree, const
> > char *,
> > unsigned HOST_WIDE_INT, unsigned);
> > extern void x86_elf_aligned_decl_common (FILE *, tree, const char *,
> > unsigned HOST_WIDE_INT, unsigned);
> > +extern bool ix86_symbolic_address_p (rtx x);
> >
> > #ifdef RTX_CODE
> > extern void ix86_fp_comparison_codes (enum rtx_code code, enum rtx_code *,
> > diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
> > index 86752a6516a..76728d10c8d 100644
> > --- a/gcc/config/i386/i386.cc
> > +++ b/gcc/config/i386/i386.cc
> > @@ -23956,6 +23956,13 @@ ix86_push_rounding (poly_int64 bytes)
> > return ROUND_UP (bytes, UNITS_PER_WORD);
> > }
> >
> > +bool ix86_symbolic_address_p (rtx x)
> > +{
> > + poly_int64 offset;
> > + x = strip_offset (x, &offset);
> > + return SYMBOL_REF_P (x) || LABEL_REF_P (x);
> > +}
> > +
> > /* Target-specific selftests. */
> >
> > #if CHECKING_P
> > diff --git a/gcc/testsuite/gcc.target/i386/pr105576.c
> > b/gcc/testsuite/gcc.target/i386/pr105576.c
> > new file mode 100644
> > index 00000000000..06dd860d3f3
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr105576.c
> > @@ -0,0 +1,11 @@
> > +/* PR target/105576 */
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mcmodel=large" } */
> > +
> > +extern int var;
> > +void *addr(void) { return &var; }
> > +void addr_via_asm(void)
> > +{
> > + asm (".pushsection .xxx,\"aw\"\n\t .dc.a %0\n\t .popsection" ::
> > "Ws"(addr));
> > + asm (".pushsection .xxx,\"aw\"\n\t .dc.a %0\n\t .popsection" ::
> > "Ws"(&var));
> > +}
> > --
> > 2.18.1
> >
