[Bug middle-end/29253] expand_abs wrong default code for floating point

[Bug middle-end/29253] expand_abs wrong default code for floating point

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2008-02-04 14:27:46         |2021-8-8

--- Comment #12 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This is still true as far as I can tell by reading the code.
The case where it will happen is REAL_MODE_FORMAT does not have a simple sign
bit or 

GET_MODE_SIZE (mode) <= UNITS_PER_WORD && the mode does not exist

Which I think the first is true for IBM 128bit long doubles.

Note I don't know if IBM 128bit long double is an important use case.

[Bug middle-end/29253] expand_abs wrong default code for floating point

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

--- Comment #13 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 55235
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55235&action=edit
Slightly different patch

This is a slightly different patch but it basically does the same except it
uses emit_library_call_value instead of creating trees to the expanding.

[Bug middle-end/29253] expand_abs wrong default code for floating point

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #55235|0                           |1
        is obsolete|                            |

--- Comment #14 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 55236
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55236&action=edit
Updated patch which I did some light testing on powerpc64-linux-gnu (with
-msoft-float)

I updated the patch because I noticed that we need to move the result of the
libcall to a temp register otherwise it might be removed.

I tested all of the testcases in this bug report with  -mlong-double-128
-msoft-float and we get the call to absl in the assembly output and they all
look correct.

[Bug middle-end/29253] expand_abs wrong default code for floating point

[bergner at gcc dot gnu dot org]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
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------- Comment #11 from bergner at gcc dot gnu dot org  2008-02-05 19:34 -------
Now we get a different ICE with the following test case:

bergner@etna:~/gcc/PR29253/bugs> cat _abs_r16.f95 
elemental function _gfortran_specific__abs_r16 (parm)
   real (kind=16), intent (in) :: parm
   real (kind=16) :: _gfortran_specific__abs_r16
   _gfortran_specific__abs_r16 = abs (parm)
end function
bergner@etna:~/gcc/PR29253/bugs>
/home/bergner/gcc/PR29253/build/gcc-mainline-patched-v2/./gcc/gfortran
-B/home/bergner/gcc/PR29253/build/gcc-mainline-patched-v2/./gcc/ 
-fallow-leading-underscore -O0 -msoft-float -c _abs_r16.f95
_abs_r16.f95: In function ‘_gfortran_specific__abs_r16’:
_abs_r16.f95:4: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


GDB backtrace:

Program received signal SIGSEGV, Segmentation fault.
build_fold_addr_expr (t=0x0) at
/home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/fold-const.c:7905
7905                                               build_pointer_type
(TREE_TYPE (t)),
(gdb) bt 5
#0  build_fold_addr_expr (t=0x0) at
/home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/fold-const.c:7905
#1  0x101d16bc in expand_expr_real_1 (exp=0xf7ed2920, target=0xf7ed2c60,
tmode=TFmode, modifier=EXPAND_NORMAL, 
    alt_rtl=<value optimized out>) at
/home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/expr.c:8757
#2  0x101d16bc in expand_expr_real_1 (exp=0xf7ed2920, target=0xf7ed2c60,
tmode=TFmode, modifier=EXPAND_NORMAL, 
    alt_rtl=<value optimized out>) at
/home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/expr.c:8757
#3  0x101d16bc in expand_expr_real_1 (exp=0xf7ed2920, target=0xf7ed2c60,
tmode=TFmode, modifier=EXPAND_NORMAL, 
    alt_rtl=<value optimized out>) at
/home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/expr.c:8757
#4  0x101d16bc in expand_expr_real_1 (exp=0xf7ed2920, target=0xf7ed2c60,
tmode=TFmode, modifier=EXPAND_NORMAL, 
    alt_rtl=<value optimized out>) at
/home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/expr.c:8757
(More stack frames follow...)
(gdb) frame 1
#1  0x101d16bc in expand_expr_real_1 (exp=0xf7ed2920, target=0xf7ed2c60,
tmode=TFmode, modifier=EXPAND_NORMAL, 
    alt_rtl=<value optimized out>) at
/home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/expr.c:8757
8757              tree call = build_fold_addr_expr (mathfn_built_in (type,
BUILT_IN_FABS));
(gdb) ptree exp
 <abs_expr 0xf7ed2920
    type <real_type 0xf7e9ac40 real(kind=16) TF
        size <integer_cst 0xf7fd7870 constant invariant 128>
        unit size <integer_cst 0xf7fd78a0 constant invariant 16>
        align 128 symtab 0 alias set -1 canonical type 0xf7e9ac40 precision 128
        pointer_to_this <pointer_type 0xf7e9ad90> reference_to_this
<reference_type 0xf7ed19a0>>

    arg 0 <var_decl 0xf7ed1af0 D.602 type <real_type 0xf7e9ac40 real(kind=16)>
        used ignored TF file _abs_r16.f95 line 5 col 0 size <integer_cst
0xf7fd7870 128> unit size <integer_cst 0xf7fd78a0 16>
        align 128 context <function_decl 0xf7ed3600
_gfortran_specific__abs_r16>
        (reg:TF 121 [ D.602 ])
        chain <var_decl 0xf7ed1b60 __result__gfortran_specific__.0 type
<real_type 0xf7e9ac40 real(kind=16)>
            used ignored TF file _abs_r16.f95 line 5 col 0 size <integer_cst
0xf7fd7870 128> unit size <integer_cst 0xf7fd78a0 16>
            align 128 context <function_decl 0xf7ed3600
_gfortran_specific__abs_r16>
            (reg:TF 120 [ __result__gfortran_specific__.0 ]) chain <var_decl
0xf7ed1bd0 D.604>>>>     
(gdb) pr target
(reg:TF 120 [ __result__gfortran_specific__.0 ])


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[bergner at gcc dot gnu dot org]

------- Comment #10 from bergner at gcc dot gnu dot org  2008-02-05 16:38 -------
Bootstrap and regtesting is in progress on the new patch.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2008-02-05 10:54 -------
Created an attachment (id=15098)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15098&action=view)
patch

Try this instead.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #15093|0                           |1
        is obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[bergner at gcc dot gnu dot org]

------- Comment #8 from bergner at gcc dot gnu dot org  2008-02-04 17:04 -------
Ok, I bootstrapped with revision 132091.  The patched compiler ICE's on the
following test case:

typedef float TFtype __attribute__ ((mode (TF)));
TFtype
divtc3 (TFtype a, TFtype b)
{
  if (__builtin_fabsl (a) < __builtin_fabsl (b))
    {
      return a;
    }
  return b;
}

Here's a backtrace from the non debug build:

Program received signal SIGSEGV, Segmentation fault.
0x105475d4 in commutative_operand_precedence (op=0x0)
    at /home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/rtlanal.c:2886
2886      enum rtx_code code = GET_CODE (op);
(gdb) bt
#0  0x105475d4 in commutative_operand_precedence (op=0x0)
    at /home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/rtlanal.c:2886
#1  0x105478b8 in swap_commutative_operands_p (x=0x0, y=0x0)
    at /home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/rtlanal.c:2951
#2  0x10212b1c in do_compare_rtx_and_jump (op0=0x0, op1=0x0, code=LT,
unsignedp=0, mode=TFmode, size=0x0, 
    if_false_label=0x0, if_true_label=0xf7f02b70)
    at /home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/dojump.c:837
#3  0x10213edc in do_compare_and_jump (exp=0xf7f022a0, signed_code=LT,
unsigned_code=LTU, if_false_label=0x0, 
    if_true_label=0xf7f02b70) at
/home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/dojump.c:1014
#4  0x1020f4cc in do_jump (exp=0xf7f022a0, if_false_label=0x0,
if_true_label=0xf7f02b70)
    at /home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/dojump.c:396
#5  0x1020c138 in jumpif (exp=0xf7f022a0, label=0xf7f02b70)
    at /home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/dojump.c:109
#6  0x10b42a44 in expand_gimple_cond_expr (bb=0xf7f0f6c0, stmt=0xf7f02300)
    at /home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/cfgexpand.c:1315
#7  0x10b43c44 in expand_gimple_basic_block (bb=0xf7f0f6c0)
    at /home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/cfgexpand.c:1578
#8  0x10b45dc0 in tree_expand_cfg () at
/home/bergner/gcc/PR29253/gcc-mainline-patched/gcc/cfgexpand.c:1921
[snip]


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[bergner at gcc dot gnu dot org]

------- Comment #7 from bergner at gcc dot gnu dot org  2008-02-04 16:30 -------
I'm testing the patch from Comment #4 on powerpc64-linux.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2008-02-04 15:07 -------
Uh, and we fold ABS <x> != 0.0 to x != 0.0, which makes the testcase
uninteresting as well.  Also it happens that for double we succeed with
generating the nojump variant.  And I don't have a cross with long-double
enabled appearantly.  So, _possibly_ better testcase :)

extern long double fabsl(double);
extern void abort(void);
long double zero = 0.0L;
void __attribute__((noinline)) foo(long double x)
{
  if (fabsl (x) != zero)
    abort ();
}
int main ()
{
  foo(-0.0L);
  return 0;
}


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2008-02-04 14:57 -------
Executable testcase:

extern double fabs(double);
extern void abort(void);
void __attribute__((noinline)) foo(double x)
{
  if (fabs (x) != 0.0)
    abort ();
}
int main ()
{
  foo(-0.0);
  return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2008-02-04 14:51 -------
Created an attachment (id=15093)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15093&action=view)
patch

This should fix it.  Can someone test it on ppc please?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[dje at gcc dot gnu dot org]

------- Comment #3 from dje at gcc dot gnu dot org  2008-02-04 14:27 -------
main ()
{
  if (fabs (-0.0) != 0.0)
    abort ();
}

compile with -msoft-float and optimization on powerpc-linux.


-- 

dje at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
   Last reconfirmed|2006-09-28 09:59:18         |2008-02-04 14:27:46
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[steven at gcc dot gnu dot org]

------- Comment #2 from steven at gcc dot gnu dot org  2008-02-03 14:37 -------
Test case and HOWTO reproduce would be welcome.


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253

[Bug middle-end/29253] expand_abs wrong default code for floating point

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2006-09-28 09:59 -------
Confirmed.  As expand_copysign, expand_fabs should defer to the library in this
case.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-09-28 09:59:18
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29253