[Bug middle-end/37710] When peeling an ordinary label off a case-table and making it a default label, strip from the end with identical labels.

[Bug middle-end/37710] When peeling an ordinary label off a case-table and making it a default label, strip from the end with identical labels.

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37710

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note we almost optimize out the testcase now to just:
  <bb 2> [local count: 1073741819]:
  typenum.0_1 = (unsigned int) typenum_4(D);
  _2 = typenum.0_1 + 34;
  if (_2 > 33)
    goto <bb 6>; [34.00%]
  else
    goto <bb 3>; [66.00%]

  <bb 3> [local count: 708669597]:
  _10 = (unsigned int) typenum_4(D);
  _5 = 4294967294 - _10;
  if (_5 <= 1)
    goto <bb 5>; [33.33%]
  else
    goto <bb 4>; [66.67%]

  <bb 4> [local count: 472446402]:

  <bb 5> [local count: 708669603]:
  # prephitmp_8 = PHI <105(4), 115(3)>

  <bb 6> [local count: 1073741824]:
  # _3 = PHI <0(2), prephitmp_8(5)>
  return _3;

Not the problem described here is fixed, just the testcase does not hit it any
more.
Note we currently produce much better code than even LLVM which still does:
        movl    $.L.str, %ecx
        cmpl    $32, %eax
        ja      .LBB0_3
# %bb.2:
        cltq
        movq    .Lswitch.table.main(,%rax,8), %rcx
.LBB0_3:
        movsbl  (%rcx), %eax

[Bug middle-end/37710] When peeling an ordinary label off a case-table and making it a default label, strip from the end with identical labels.

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37710

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is a new testcase:
extern void abort (void);

extern char *name1;
extern char *name2;

int stab_xcoff_builtin_type (int typenum) __attribute__((noclone,noinline));
int stab_xcoff_builtin_type (int typenum)
{
  const char *name;
  if (typenum >= 0 || typenum < -34)
    {
      return 0;
    }
  switch (-typenum)
    {
    case 1:
      name = name1;"int";
      break;
    case 2:
      name = "char";
    case 3:
      name = name2;"short";
      break;
    case 4:
      name = "long";
      break;
    case 5:
      name = "unsigned char";
      break;
    case 6:
      name = "signed char";
      break;
    case 7:
      name = "unsigned short";
      break;
    case 8:
      name = "unsigned int";
      break;
    case 9:
      name = "unsigned";
      break;
    case 10:
      name = "unsigned long";
      break;
    case 11:
      name = "void";
      break;
    case 12:
      name = "float";
      break;
    case 13:
      name = "double";
      break;
    case 14:
      name = "long double";
      break;
    case 15:
      name = "integer";
      break;
    case 16:
      name = "boolean";
      break;
    case 17:
      name = "short real";
      break;
    case 18:
      name = "real";
      break;
    case 19:
      name = "stringptr";
      break;
    case 20:
      name = "character";
      break;
    case 21:
      name = "logical*1";
      break;
    case 22:
      name = "logical*2";
      break;
    case 23:
      name = "logical*4";
      break;
    case 24:
      name = "logical";
      break;
    case 25:
      name = "complex";
      break;
    case 26:
      name = "double complex";
      break;
    case 27:
      name = "integer*1";
      break;
    case 28:
      name = "integer*2";
      break;
    case 29:
      name = "integer*4";
      break;
    case 30:
      name = "wchar";
    case 31:
      name = "long long";
      break;
    case 32:
      name = "unsigned long long";
      break;
    case 33:
      name = "logical*8";
      break;
    case 34:
      name = "integer*8";
      break;
    }
  return name[0];
}

int main()
{
  int i;
  if (stab_xcoff_builtin_type(0) != 0)
    abort ();
  if (stab_xcoff_builtin_type(-1) != 'i')
    abort ();
  if (stab_xcoff_builtin_type(-2) != 's')
    abort ();
  if (stab_xcoff_builtin_type(-3) != 's')
    abort ();
  for (i = -4; i >= -34; --i)
    if (stab_xcoff_builtin_type(i) != 'i')
      abort ();
  if (stab_xcoff_builtin_type(-35) != 0)
    abort ();
  return 0;
}

[Bug middle-end/37710] When peeling an ordinary label off a case-table and making it a default label, strip from the end with identical labels.

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37710

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
and yes we get code that looks like:
        xorl    %eax, %eax
        cmpl    $-34, %edi
        jb      .L1
        negl    %edi
        cmpl    $34, %edi
        ja      .L3
        jmp     *.L5(,%rdi,8)
        .section        .rodata
        .align 8
        .align 4
.L5:
        .quad   .L3
        .quad   .L3

Even though we should something like:
        xorl    %eax, %eax
        cmpl    $-34, %edi
        jb      .L1
        negl    %edi
        jmp     *.L5(,%rdi,8)
        .section        .rodata
        .align 8
        .align 4
.L5:
        .quad   .L3

[Bug middle-end/37710] When peeling an ordinary label off a case-table and making it a default label, strip from the end with identical labels.

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2008-10-02 11:08 -------
This basically boils down to moving optimizing case labels earlier (we do
so after going out-of-ssa).


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2008-10-02 11:08:25
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37710