[x86] Refine constraint "Bk" to define_special_memory_constraint.

For below pattern, RA may still allocate r162 as v/k register, try to
reload for address with leaq __libc_tsd_CTYPE_B@gottpoff(%rip), %rsi
which result a linker error.

(set (reg:DI 162)
     (mem/u/c:DI
       (const:DI (unspec:DI
		 [(symbol_ref:DI ("a") [flags 0x60]  <var_decl 0x7f621f6e1c60 a>)]
		 UNSPEC_GOTNTPOFF))

Quote from H.J for why linker issue an error.
>What do these do:
>
>        leaq    __libc_tsd_CTYPE_B@gottpoff(%rip), %rax
>        vmovq   (%rax), %xmm0
>
>From x86-64 TLS psABI:
>
>The assembler generates for the x@gottpoff(%rip) expressions a R X86
>64 GOTTPOFF relocation for the symbol x which requests the linker to
>generate a GOT entry with a R X86 64 TPOFF64 relocation. The offset of
>the GOT entry relative to the end of the instruction is then used in
>the instruction. The R X86 64 TPOFF64 relocation is pro- cessed at
>program startup time by the dynamic linker by looking up the symbol x
>in the modules loaded at that point. The offset is written in the GOT
>entry and later loaded by the addq instruction.
>
>The above code sequence looks wrong to me.

Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok for trunk and backport?

gcc/ChangeLog:

	PR target/116043
	* config/i386/constraints.md (Bk): Refine to
	define_special_memory_constraint.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr116043.c: New test.
---
 gcc/config/i386/constraints.md           |  2 +-
 gcc/testsuite/gcc.target/i386/pr116043.c | 33 ++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr116043.c

On Wed, Jul 24, 2024 at 3:57 PM liuhongt <hongtao.liu@intel.com> wrote:
>
> For below pattern, RA may still allocate r162 as v/k register, try to
> reload for address with leaq __libc_tsd_CTYPE_B@gottpoff(%rip), %rsi
> which result a linker error.
>
> (set (reg:DI 162)
>      (mem/u/c:DI
>        (const:DI (unspec:DI
>                  [(symbol_ref:DI ("a") [flags 0x60]  <var_decl 0x7f621f6e1c60 a>)]
>                  UNSPEC_GOTNTPOFF))
>
> Quote from H.J for why linker issue an error.
> >What do these do:
> >
> >        leaq    __libc_tsd_CTYPE_B@gottpoff(%rip), %rax
> >        vmovq   (%rax), %xmm0
> >
> >From x86-64 TLS psABI:
> >
> >The assembler generates for the x@gottpoff(%rip) expressions a R X86
> >64 GOTTPOFF relocation for the symbol x which requests the linker to
> >generate a GOT entry with a R X86 64 TPOFF64 relocation. The offset of
> >the GOT entry relative to the end of the instruction is then used in
> >the instruction. The R X86 64 TPOFF64 relocation is pro- cessed at
> >program startup time by the dynamic linker by looking up the symbol x
> >in the modules loaded at that point. The offset is written in the GOT
> >entry and later loaded by the addq instruction.
> >
> >The above code sequence looks wrong to me.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> Ok for trunk and backport?
>
> gcc/ChangeLog:
>
>         PR target/116043
>         * config/i386/constraints.md (Bk): Refine to
>         define_special_memory_constraint.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.target/i386/pr116043.c: New test.
> ---
>  gcc/config/i386/constraints.md           |  2 +-
>  gcc/testsuite/gcc.target/i386/pr116043.c | 33 ++++++++++++++++++++++++
>  2 files changed, 34 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr116043.c
>
> diff --git a/gcc/config/i386/constraints.md b/gcc/config/i386/constraints.md
> index 7508d7a58bd..b760e7c221a 100644
> --- a/gcc/config/i386/constraints.md
> +++ b/gcc/config/i386/constraints.md
> @@ -187,7 +187,7 @@ (define_special_memory_constraint "Bm"
>    "@internal Vector memory operand."
>    (match_operand 0 "vector_memory_operand"))
>
> -(define_memory_constraint "Bk"
> +(define_special_memory_constraint "Bk"
>    "@internal TLS address that allows insn using non-integer registers."
>    (and (match_operand 0 "memory_operand")
>         (not (match_test "ix86_gpr_tls_address_pattern_p (op)"))))
> diff --git a/gcc/testsuite/gcc.target/i386/pr116043.c b/gcc/testsuite/gcc.target/i386/pr116043.c
> new file mode 100644
> index 00000000000..76553496c10
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr116043.c
> @@ -0,0 +1,33 @@
> +/* { dg-do compile } */
> +/* { dg-options "-mavx512bf16 -O3" } */
> +/* { dg-final { scan-assembler-not {(?n)lea.*@gottpoff} } } */
> +
> +extern __thread int a, c, i, j, k, l;
> +int *b;
> +struct d {
> +  int e;
> +} f, g;
> +char *h;
> +
> +void m(struct d *n) {
> +  b = &k;
> +  for (; n->e; b++, n--) {
> +    i = b && a;
> +    if (i)
> +      j = c;
> +  }
> +}
> +
> +char *o(struct d *n) {
> +  for (; n->e;)
> +    return h;
> +}
> +
> +int q() {
> +  if (l)
> +    return 1;
> +  int p = *o(&g);
> +  m(&f);
> +  m(&g);
> +  l = p;
> +}
> --
> 2.31.1
>

On Thu, Jul 25, 2024 at 3:23 PM Hongtao Liu <crazylht@gmail.com> wrote:
>
> On Wed, Jul 24, 2024 at 3:57 PM liuhongt <hongtao.liu@intel.com> wrote:
> >
> > For below pattern, RA may still allocate r162 as v/k register, try to
> > reload for address with leaq __libc_tsd_CTYPE_B@gottpoff(%rip), %rsi
> > which result a linker error.
> >
> > (set (reg:DI 162)
> >      (mem/u/c:DI
> >        (const:DI (unspec:DI
> >                  [(symbol_ref:DI ("a") [flags 0x60]  <var_decl 0x7f621f6e1c60 a>)]
> >                  UNSPEC_GOTNTPOFF))
> >
> > Quote from H.J for why linker issue an error.
> > >What do these do:
> > >
> > >        leaq    __libc_tsd_CTYPE_B@gottpoff(%rip), %rax
> > >        vmovq   (%rax), %xmm0
> > >
> > >From x86-64 TLS psABI:
> > >
> > >The assembler generates for the x@gottpoff(%rip) expressions a R X86
> > >64 GOTTPOFF relocation for the symbol x which requests the linker to
> > >generate a GOT entry with a R X86 64 TPOFF64 relocation. The offset of
> > >the GOT entry relative to the end of the instruction is then used in
> > >the instruction. The R X86 64 TPOFF64 relocation is pro- cessed at
> > >program startup time by the dynamic linker by looking up the symbol x
> > >in the modules loaded at that point. The offset is written in the GOT
> > >entry and later loaded by the addq instruction.
> > >
> > >The above code sequence looks wrong to me.
> >
> > Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> > Ok for trunk and backport?
Committed and will backport after gcc14.2 is released.
> >
> > gcc/ChangeLog:
> >
> >         PR target/116043
> >         * config/i386/constraints.md (Bk): Refine to
> >         define_special_memory_constraint.
> >
> > gcc/testsuite/ChangeLog:
> >
> >         * gcc.target/i386/pr116043.c: New test.
> > ---
> >  gcc/config/i386/constraints.md           |  2 +-
> >  gcc/testsuite/gcc.target/i386/pr116043.c | 33 ++++++++++++++++++++++++
> >  2 files changed, 34 insertions(+), 1 deletion(-)
> >  create mode 100644 gcc/testsuite/gcc.target/i386/pr116043.c
> >
> > diff --git a/gcc/config/i386/constraints.md b/gcc/config/i386/constraints.md
> > index 7508d7a58bd..b760e7c221a 100644
> > --- a/gcc/config/i386/constraints.md
> > +++ b/gcc/config/i386/constraints.md
> > @@ -187,7 +187,7 @@ (define_special_memory_constraint "Bm"
> >    "@internal Vector memory operand."
> >    (match_operand 0 "vector_memory_operand"))
> >
> > -(define_memory_constraint "Bk"
> > +(define_special_memory_constraint "Bk"
> >    "@internal TLS address that allows insn using non-integer registers."
> >    (and (match_operand 0 "memory_operand")
> >         (not (match_test "ix86_gpr_tls_address_pattern_p (op)"))))
> > diff --git a/gcc/testsuite/gcc.target/i386/pr116043.c b/gcc/testsuite/gcc.target/i386/pr116043.c
> > new file mode 100644
> > index 00000000000..76553496c10
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr116043.c
> > @@ -0,0 +1,33 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-mavx512bf16 -O3" } */
> > +/* { dg-final { scan-assembler-not {(?n)lea.*@gottpoff} } } */
> > +
> > +extern __thread int a, c, i, j, k, l;
> > +int *b;
> > +struct d {
> > +  int e;
> > +} f, g;
> > +char *h;
> > +
> > +void m(struct d *n) {
> > +  b = &k;
> > +  for (; n->e; b++, n--) {
> > +    i = b && a;
> > +    if (i)
> > +      j = c;
> > +  }
> > +}
> > +
> > +char *o(struct d *n) {
> > +  for (; n->e;)
> > +    return h;
> > +}
> > +
> > +int q() {
> > +  if (l)
> > +    return 1;
> > +  int p = *o(&g);
> > +  m(&f);
> > +  m(&g);
> > +  l = p;
> > +}
> > --
> > 2.31.1
> >
>
>
> --
> BR,
> Hongtao