On Thu, Aug 31, 2017 at 9:32 PM, Uros Bizjak <ubiz...@gmail.com> wrote:
> Hello!
>
> Using following testcase:
>
> --cut here--
> __thread int a;
>
> int foo (void)
> {
> return a;
> }
> --cut here--
>
> Attached patch converts TLS location in the form of:
>
> (mem/c:SI (plus:DI (unspec:DI [
> (const_int 0 [0])
> ] UNSPEC_TP)
> (const:DI (unspec:DI [
> (symbol_ref:DI ("a") [flags 0x2a]
> <var_decl 0x7f8c3acd5e10 a>)
> ] UNSPEC_NTPOFF))) [1 a+0 S4 A32]))
> "thread.c":5 82 {*movsi_internal}
> to:
>
> (mem/c:SI (const:DI (unspec:DI [
> (symbol_ref:DI ("a") [flags 0x2a] <var_decl
> 0x7f8c3acd5e10 a>)
> ] UNSPEC_NTPOFF)) [1 a+0 S4 A32 AS1])) "thread.c":5 -1
>
> avoiding the UNSPEC_TP tag and instead mark the location with AS.
>
> This way, address space becomes the property of the memory location,
> not of the address itself, so we don't need ugly hacks when the
> address is moved to a register (LEA ignores segment overrides, c.f.
> split_long_move function in i386.c).
>
> Please note that some instructions (e.g. prefetchX) operate on
> prefixed *address*, so we can't just rip out non-AS code from
> print_operand. The above amended example:
>
> --cut here--
> __thread int a;
>
> int foo (void)
> {
> __builtin_prefetch (&a, 0);
> return a;
> }
> --cut here--
>
> compiles to:
>
> prefetcht0 %fs:a@tpoff
> movl %fs:a@tpoff, %eax
>
> where prefetch operand remains:
>
> (insn 7 6 16 2 (prefetch (plus:DI (unspec:DI [
> (const_int 0 [0])
> ] UNSPEC_TP)
> (const:DI (unspec:DI [
> (symbol_ref:DI ("a") [flags 0x2a] <var_decl
> 0x7fe994a14e10 a>)
> ] UNSPEC_NTPOFF)))
> (const_int 0 [0])
> (const_int 3 [0x3])) "thread.c":5 1010 {*prefetch_sse}
> (nil))
>
> 2017-08-31 Uros Bizjak <ubiz...@gmail.com>
>
> * config/i386/i386-protos.h (ix86_tls_address_pattern_p) New prototype.
> (ix86_rewrite_tls_address): Ditto.
> * config/i386/i386.c (ix86_tls_address_pattern_p) New function.
> (ix86_rewrite_tls_address_1): Ditto.
> (ix86_rewrite_tls_address): Ditto.
> * config/i386/predicates.md (tls_address_pattern): New predicate.
> * config/i386/i386.md (TLS address splitter): New splitter.
>
> Patch was bootstrapped and regression tested on x86_64-linux-gnu
> {,-m32}, all default languages plus go.
>
> I plan to commit the patch to the mainline early next week.
Committed to mainline SVN.
Uros
