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Re: [patch i386]: Expand sibling-tail-calls via accumulator register


On Wed, May 28, 2014 at 1:43 AM, Kai Tietz <ktietz@redhat.com> wrote:
> Hi,
>
> I modified prior patch so that it uses the new predicate sibcall_memory_operand to extend sibcall_insn_operand.
> Just one change in i386.c remains about x86_output_mi_thunk.  Later one isn't pretty much essential.  Nevertheless it makes
> code equivalent to none-memory-case for potential tail-sibcalls.
>
> ChangeLog gcc
>
> 2014-05-28  Kai Tietz  <ktietz@redhat.com>
>
>         * config/i386/i386.c (x86_output_mi_thunk): Add memory case
>         for sibling-tail-calls.
>         * config/i386/i386.md (sibcall_insn_operand): Add memory-constrain
>         to its use.
>         * config/i386/predicates.md (sibcall_memory_operand): New predicate.
>         (sibcall_insn_operand): Add check for sibcall_memory_operand.
>
> ChangeLog testsuite
>
> 2014-05-28  Kai Tietz  <ktietz@redhat.com>
>
>         PR target/60104
>         * gcc.target/i386/sibcall-1.c: New test.
>         * gcc.target/i386/sibcall-2.c: New test.
>         * gcc.target/i386/sibcall-3.c: New test.
>
> Regression tested x86_64-unknown-linux-gnu multilib, x86_64-w64-mingw32, and i686-pc-cygwin.  Ok for apply?
>
> Regards,
> Kai
>
>
> Index: gcc/config/i386/i386.c
> ===================================================================
> --- gcc/config/i386/i386.c      (revision 210985)
> +++ gcc/config/i386/i386.c      (working copy)
> @@ -38893,7 +38893,16 @@ x86_output_mi_thunk (FILE *file,
>       For our purposes here, we can get away with (ab)using a jump pattern,
>       because we're going to do no optimization.  */
>    if (MEM_P (fnaddr))
> -    emit_jump_insn (gen_indirect_jump (fnaddr));
> +    {
> +      if (sibcall_insn_operand (fnaddr, word_mode))
> +       {
> +         tmp = gen_rtx_CALL (VOIDmode, fnaddr, const0_rtx);
> +          tmp = emit_call_insn (tmp);
> +          SIBLING_CALL_P (tmp) = 1;
> +       }
> +      else
> +       emit_jump_insn (gen_indirect_jump (fnaddr));
> +    }
>    else
>      {
>        if (ix86_cmodel == CM_LARGE_PIC && SYMBOLIC_CONST (fnaddr))
> Index: gcc/config/i386/i386.md
> ===================================================================
> --- gcc/config/i386/i386.md     (revision 210985)
> +++ gcc/config/i386/i386.md     (working copy)
> @@ -11376,7 +11376,7 @@
>    [(set_attr "type" "call")])
>
>  (define_insn "*sibcall"
> -  [(call (mem:QI (match_operand:W 0 "sibcall_insn_operand" "Uz"))
> +  [(call (mem:QI (match_operand:W 0 "sibcall_insn_operand" "Uzm"))
>          (match_operand 1))]
>    "SIBLING_CALL_P (insn)"
>    "* return ix86_output_call_insn (insn, operands[0]);"
> @@ -11406,7 +11406,7 @@
>    [(set_attr "type" "call")])
>
>  (define_insn "*sibcall_pop"
> -  [(call (mem:QI (match_operand:SI 0 "sibcall_insn_operand" "Uz"))
> +  [(call (mem:QI (match_operand:SI 0 "sibcall_insn_operand" "Uzm"))
>          (match_operand 1))
>     (set (reg:SI SP_REG)
>         (plus:SI (reg:SI SP_REG)
> @@ -11451,7 +11451,7 @@
>
>  (define_insn "*sibcall_value"
>    [(set (match_operand 0)
> -       (call (mem:QI (match_operand:W 1 "sibcall_insn_operand" "Uz"))
> +       (call (mem:QI (match_operand:W 1 "sibcall_insn_operand" "Uzm"))
>               (match_operand 2)))]
>    "SIBLING_CALL_P (insn)"
>    "* return ix86_output_call_insn (insn, operands[1]);"
> @@ -11494,7 +11494,7 @@
>
>  (define_insn "*sibcall_value_pop"
>    [(set (match_operand 0)
> -       (call (mem:QI (match_operand:SI 1 "sibcall_insn_operand" "Uz"))
> +       (call (mem:QI (match_operand:SI 1 "sibcall_insn_operand" "Uzm"))
>               (match_operand 2)))
>     (set (reg:SI SP_REG)
>         (plus:SI (reg:SI SP_REG)
> Index: gcc/config/i386/predicates.md
> ===================================================================
> --- gcc/config/i386/predicates.md       (revision 210985)
> +++ gcc/config/i386/predicates.md       (working copy)
> @@ -71,6 +71,16 @@
>    return ANY_QI_REG_P (op);
>  })
>
> +(define_predicate "sibcall_memory_operand"
> +  (match_operand 0 "memory_operand")
> +{
> +  op = XEXP (op, 0);
> +
> +  if (GET_CODE (op) == CONST)
> +    op = XEXP (op, 0);
> +  return (GET_CODE (op) == SYMBOL_REF || CONSTANT_P (op));
> +})
> +
>  ;; Match an SI or HImode register for a zero_extract.
>  (define_special_predicate "ext_register_operand"
>    (match_operand 0 "register_operand")
> @@ -600,7 +610,9 @@
>  (define_special_predicate "sibcall_insn_operand"
>    (ior (match_test "constant_call_address_operand
>                      (op, mode == VOIDmode ? mode : Pmode)")
> -       (match_operand 0 "register_no_elim_operand")))
> +       (match_operand 0 "register_no_elim_operand")
> +       (and (not (match_test "TARGET_X32"))
> +           (match_operand 0 "sibcall_memory_operand"))))
>
>  ;; Return true if OP is a call from MS ABI to SYSV ABI function.
>  (define_predicate "call_rex64_ms_sysv_operation"
> Index: gcc/testsuite/gcc.target/i386/sibcall-1.c
> ===================================================================
> --- gcc/testsuite/gcc.target/i386/sibcall-1.c   (revision 0)
> +++ gcc/testsuite/gcc.target/i386/sibcall-1.c   (working copy)
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target ia32 } */
> +/* { dg-options "-O2" } */
> +
> +extern int (*foo)(int);
> +
> +int boo (int a)
> +{
> +  return (*foo) (a);
> +}
> +
> +/* { dg-final { scan-assembler-not "mov" } } */
> Index: gcc/testsuite/gcc.target/i386/sibcall-2.c
> ===================================================================
> --- gcc/testsuite/gcc.target/i386/sibcall-2.c   (revision 0)
> +++ gcc/testsuite/gcc.target/i386/sibcall-2.c   (working copy)
> @@ -0,0 +1,16 @@
> +/* { dg-do compile { xfail { *-*-* } } } */
> +/* { dg-require-effective-target ia32 } */
> +/* { dg-options "-O2" } */
> +
> +extern int doo1 (int);
> +extern int doo2 (int);
> +extern void bar (char *);
> +
> +int foo (int a)
> +{
> +  char s[256];
> +  bar (s);
> +  return (a < 0 ? doo1 : doo2) (a);
> +}
> +
> +/* { dg-final { scan-assembler-not "call[ \t]*.%eax" } } */
> Index: gcc/testsuite/gcc.target/i386/sibcall-3.c
> ===================================================================
> --- gcc/testsuite/gcc.target/i386/sibcall-3.c   (revision 0)
> +++ gcc/testsuite/gcc.target/i386/sibcall-3.c   (working copy)
> @@ -0,0 +1,16 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target ia32 } */
> +/* { dg-options "-O2" } */
> +
> +extern
> +#ifdef _WIN32
> + __declspec (dllimport)
> +#endif
> + void foo (int a);
> +
> +void bar (int a)
> +{
> +  return foo (a);
> +}
> +
> +/* { dg-final { scan-assembler-not "jmp[ \t]*.%eax" } } */
> Index: gcc/testsuite/gcc.target/i386/sibcall-4.c
> ===================================================================
> --- gcc/testsuite/gcc.target/i386/sibcall-4.c   (revision 0)
> +++ gcc/testsuite/gcc.target/i386/sibcall-4.c   (working copy)
> @@ -0,0 +1,15 @@
> +/* Testcase for PR target/46219.  */
> +/* { dg-do compile { xfail { *-*-* } } */
> +/* { dg-require-effective-target ia32 } */
> +/* { dg-options "-O2" } */
> +
> +typedef void (*dispatch_t)(long offset);
> +
> +dispatch_t dispatch[256];
> +
> +void male_indirect_jump (long offset)
> +{
> +  dispatch[offset](offset);
> +}
> +
> +/* { dg-final { scan-assembler-not "jmp[ \t]*.%eax" } } */

Shouldn't the testcases also be applied to x86-64?

-- 
H.J.


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