On Sat, Jul 26, 2025 at 7:37 PM H.J. Lu <hjl.to...@gmail.com> wrote:
>
> __tls_get_addr doesn't preserve vector registers. When a function
> with no_caller_saved_registers attribute calls __tls_get_addr, YMM
> and ZMM registers will be clobbered. Issue an error and suggest
> -mtls-dialect=gnu2 in this case.
>
> gcc/
>
> PR target/121208
> * config/i386/i386.cc (ix86_tls_get_addr): Issue an error for
> -mtls-dialect=gnu with no_caller_saved_registers attribute and
> suggest -mtls-dialect=gnu2.
>
> gcc/testsuite/
>
> PR target/121208
> * gcc.target/i386/pr121208-1a.c: New test.
> * gcc.target/i386/pr121208-1b.c: Likewise.
> * gcc.target/i386/pr121208-2a.c: Likewise.
> * gcc.target/i386/pr121208-2b.c: Likewise.
> * gcc.target/i386/pr121208-3a.c: Likewise.
> * gcc.target/i386/pr121208-3b.c: Likewise.
LGTM.
Thanks,
Uros.
>
> Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
> ---
> gcc/config/i386/i386.cc | 22 +++++++++++++++++++++
> gcc/testsuite/gcc.target/i386/pr121208-1a.c | 15 ++++++++++++++
> gcc/testsuite/gcc.target/i386/pr121208-1b.c | 4 ++++
> gcc/testsuite/gcc.target/i386/pr121208-2a.c | 17 ++++++++++++++++
> gcc/testsuite/gcc.target/i386/pr121208-2b.c | 4 ++++
> gcc/testsuite/gcc.target/i386/pr121208-3a.c | 17 ++++++++++++++++
> gcc/testsuite/gcc.target/i386/pr121208-3b.c | 4 ++++
> 7 files changed, 83 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-1a.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-1b.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-2a.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-2b.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-3a.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-3b.c
>
> diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
> index 4682db85ce4..036455a45a5 100644
> --- a/gcc/config/i386/i386.cc
> +++ b/gcc/config/i386/i386.cc
> @@ -12442,6 +12442,28 @@ static GTY(()) rtx ix86_tls_symbol;
> static rtx
> ix86_tls_get_addr (void)
> {
> + if (cfun->machine->call_saved_registers
> + == TYPE_NO_CALLER_SAVED_REGISTERS)
> + {
> + /* __tls_get_addr doesn't preserve vector registers. When a
> + function with no_caller_saved_registers attribute calls
> + __tls_get_addr, YMM and ZMM registers will be clobbered.
> + Issue an error and suggest -mtls-dialect=gnu2 in this case. */
> + if (cfun->machine->func_type != TYPE_NORMAL)
> + error (cfun->machine->func_type == TYPE_EXCEPTION
> + ? G_("%<-mtls-dialect=gnu2%> must be used with an"
> + " exception service routine")
> + : G_("%<-mtls-dialect=gnu2%> must be used with an"
> + " interrupt service routine"));
> + else
> + error (G_("%<-mtls-dialect=gnu2%> must be used with a function"
> + " with the %<no_caller_saved_registers%> attribute"));
> + /* Don't issue the same error twice. */
> + cfun->machine->func_type = TYPE_NORMAL;
> + cfun->machine->call_saved_registers
> + = TYPE_DEFAULT_CALL_SAVED_REGISTERS;
> + }
> +
> if (!ix86_tls_symbol)
> {
> const char *sym
> diff --git a/gcc/testsuite/gcc.target/i386/pr121208-1a.c
> b/gcc/testsuite/gcc.target/i386/pr121208-1a.c
> new file mode 100644
> index 00000000000..ac851cb50d8
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr121208-1a.c
> @@ -0,0 +1,15 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu" } */
> +
> +extern __thread int bar;
> +extern void func (void);
> +
> +__attribute__((no_caller_saved_registers))
> +void
> +foo (int error)
> +{
> + bar = 1; /* { dg-error -mtls-dialect=gnu2 } */
> + if (error == 0)
> + func ();
> + bar = 0;
> +}
> diff --git a/gcc/testsuite/gcc.target/i386/pr121208-1b.c
> b/gcc/testsuite/gcc.target/i386/pr121208-1b.c
> new file mode 100644
> index 00000000000..b97ac715c65
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr121208-1b.c
> @@ -0,0 +1,4 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu2" } */
> +
> +#include "pr121208-1a.c"
> diff --git a/gcc/testsuite/gcc.target/i386/pr121208-2a.c
> b/gcc/testsuite/gcc.target/i386/pr121208-2a.c
> new file mode 100644
> index 00000000000..c1891ae322c
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr121208-2a.c
> @@ -0,0 +1,17 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu" } */
> +
> +typedef unsigned int uword_t __attribute__ ((mode (__word__)));
> +extern __thread int bar;
> +extern void func (void);
> +
> +__attribute__((target("general-regs-only")))
> +__attribute__((interrupt))
> +void
> +foo (void *frame, uword_t error)
> +{
> + bar = 1; /* { dg-error -mtls-dialect=gnu2 } */
> + if (error == 0)
> + func ();
> + bar = 0;
> +}
> diff --git a/gcc/testsuite/gcc.target/i386/pr121208-2b.c
> b/gcc/testsuite/gcc.target/i386/pr121208-2b.c
> new file mode 100644
> index 00000000000..269b120f990
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr121208-2b.c
> @@ -0,0 +1,4 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu2" } */
> +
> +#include "pr121208-2a.c"
> diff --git a/gcc/testsuite/gcc.target/i386/pr121208-3a.c
> b/gcc/testsuite/gcc.target/i386/pr121208-3a.c
> new file mode 100644
> index 00000000000..26fe6870155
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr121208-3a.c
> @@ -0,0 +1,17 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu" } */
> +
> +typedef unsigned int uword_t __attribute__ ((mode (__word__)));
> +extern __thread int bar;
> +extern void func (void);
> +
> +__attribute__((target("general-regs-only")))
> +__attribute__((interrupt))
> +void
> +foo (void *frame)
> +{
> + bar = 1; /* { dg-error -mtls-dialect=gnu2 } */
> + if (frame == 0)
> + func ();
> + bar = 0;
> +}
> diff --git a/gcc/testsuite/gcc.target/i386/pr121208-3b.c
> b/gcc/testsuite/gcc.target/i386/pr121208-3b.c
> new file mode 100644
> index 00000000000..b672d751d7f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr121208-3b.c
> @@ -0,0 +1,4 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu2" } */
> +
> +#include "pr121208-3a.c"
> --
> 2.50.1
>
