[Bug c/44031] New: ice in subst_reloads, at reload.c:6327

[Bug c/44031] New: ice in subst_reloads, at reload.c:6327

[regehr at cs dot utah dot edu]

[regehr@bethe tmp600]$ current-gcc -v
Using built-in specs.
COLLECT_GCC=current-gcc
COLLECT_LTO_WRAPPER=/uusoc/exports/scratch/regehr/z/compiler-install/gcc-r159144-install/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../configure --with-libelf=/usr/local --enable-lto
--prefix=/home/regehr/z/compiler-install/gcc-r159144-install
--program-prefix=r159144- --enable-languages=c,c++
Thread model: posix
gcc version 4.6.0 20100507 (experimental) (GCC) 

[regehr@bethe tmp600]$ current-gcc -O -c small.c         

small.c: In function 'int321':
small.c:35:1: internal compiler error: in subst_reloads, at reload.c:6327
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

[regehr@bethe tmp600]$ cat small.c

typedef unsigned char uint8_t;
typedef unsigned int uint32_t;
typedef unsigned long int uint64_t;

static uint32_t
safe_add_func_uint32_t_u_u (uint32_t ui1, uint32_t ui2)
{
  return ui1 + ui2;
}

static uint64_t
safe_div_func_uint64_t_u_u (uint64_t ui1, uint32_t ui2)
{
  return ui2 ? : (ui1 / ui2);
}

uint8_t g_55;
uint8_t *g_73 = &g_55;
uint8_t **g_332 = &g_73;

int func_38(uint8_t *,int);
int func_8(int);

int int321 (void)
{
  uint8_t l_26[4];
  uint8_t *l_238 = &l_26[2];
  uint8_t l_400;
  l_400 &=
    func_38 (&l_26[3],
             safe_add_func_uint32_t_u_u (safe_div_func_uint64_t_u_u
                                         (1, **g_332),
                                         *l_238) >= *l_238 < func_8 (0)), 1;
  return 0;
}


-- 
           Summary: ice in subst_reloads, at reload.c:6327
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: regehr at cs dot utah dot edu
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44031

[Bug target/44031] [4.6 Regression] ice in subst_reloads, at reload.c:6327

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|ice in subst_reloads, at    |[4.6 Regression] ice in
                   |reload.c:6327               |subst_reloads, at
                   |                            |reload.c:6327
   Target Milestone|---                         |4.6.0
            Version|unknown                     |4.6.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44031

[Bug target/44031] [4.4/4.5/4.6 Regression] ice in subst_reloads, at reload.c:6327

[hjl dot tools at gmail dot com]

------- Comment #1 from hjl dot tools at gmail dot com  2010-05-08 00:35 -------
It failed with gcc 4.4.3 and 4.5.0.


-- 

hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2010-05-08 00:35:54
               date|                            |
            Summary|[4.6 Regression] ice in     |[4.4/4.5/4.6 Regression] ice
                   |subst_reloads, at           |in subst_reloads, at
                   |reload.c:6327               |reload.c:6327


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44031

[Bug target/44031] [4.4/4.5/4.6 Regression] ice in subst_reloads, at reload.c:6327

[hjl dot tools at gmail dot com]

------- Comment #2 from hjl dot tools at gmail dot com  2010-05-08 00:40 -------
It is caused by revision 152533:

http://gcc.gnu.org/ml/gcc-cvs/2009-10/msg00182.html


-- 

hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ubizjak at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44031

[Bug target/44031] [4.4/4.5/4.6 Regression] ice in subst_reloads, at reload.c:6327

[vmakarov at redhat dot com]

------- Comment #3 from vmakarov at redhat dot com  2010-05-10 15:22 -------

> It is caused by revision 152533:
> 
> http://gcc.gnu.org/ml/gcc-cvs/2009-10/msg00182.html
> 

If it is so, the patch triggered some reload bug IMO.  The patch itself was
very safe because it resulted in creation of additional conflicts.

I hope that Jeff Law's work on new reload will fix it when it is in 4.6
finally.  Otherwise, we should work on this PR.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44031

[Bug target/44031] [4.4/4.5/4.6 Regression] ice in subst_reloads, at reload.c:6327

[law at redhat dot com]

------- Comment #4 from law at redhat dot com  2010-05-11 05:31 -------
I doubt my work will make a significant difference for this test.

We're trying to reload an insn which matches:


(define_insn "*add<mode>3_cconly_overflow"
  [(set (reg:CCC FLAGS_REG)
        (compare:CCC
          (plus:SWI
            (match_operand:SWI 1 "nonimmediate_operand" "%0")
            (match_operand:SWI 2 "<general_operand>" "<r><i>m"))
          (match_dup 1)))
   (clobber (match_scratch:SWI 0 "=<r>"))]
  "ix86_binary_operator_ok (PLUS, <MODE>mode, operands)"
  "add{<imodesuffix>}\t{%2, %0|%0, %2}"
  [(set_attr "type" "alu")
   (set_attr "mode" "<MODE>")])

(gdb) p debug_reload()
Reload 0: reload_in (SI) = (reg:SI 6 bp)
        reload_out (SI) = (scratch:SI)
        GENERAL_REGS, RELOAD_OTHER (opnum = 0), can't combine
        reload_in_reg: (subreg:SI (reg:DI 6 bp [orig:66 D.2764 ] [66]) 0)
        reload_out_reg: (scratch:SI)
$14 = void
(gdb) p debug_rtx (insn)
(insn 25 24 26 5 j.c:26 (parallel [
            (set (reg:CCC 17 flags)
                (compare:CCC (plus:SI (subreg:SI (reg:DI 6 bp [orig:66 D.2764 ]
[66]) 0)
                        (reg:SI 3 bx [orig:58 D.2737 ] [58]))
                    (subreg:SI (reg:DI 6 bp [orig:66 D.2764 ] [66]) 0)))
            (clobber (scratch:SI))
        ]) 316 {*addsi3_cconly_overflow} (expr_list:REG_DEAD (reg:DI 6 bp
[orig:66 D.2764 ] [66])
        (expr_list:REG_DEAD (reg:SI 3 bx [orig:58 D.2737 ] [58])
            (nil))))

I think the only way to satisfy this reload is to allocate the scratch to
(subreg: SI (reg:DI 6))  I have no clue why reload doesn't do that.  


-- 

law at redhat dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at redhat dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44031

[Bug target/44031] [4.4/4.5/4.6 Regression] ice in subst_reloads, at reload.c:6327

[ubizjak at gmail dot com]

------- Comment #5 from ubizjak at gmail dot com  2010-07-25 18:06 -------
*** Bug 44816 has been marked as a duplicate of this bug. ***


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44031

[Bug target/44031] [4.4/4.5/4.6 Regression] ice in subst_reloads, at reload.c:6327

[ubizjak at gmail dot com]

------- Comment #6 from ubizjak at gmail dot com  2010-08-01 11:41 -------
FYI, following shoot-in-the-dark patch didn't help, but I guess it is needed
together with some further reload surgery:

Index: gensupport.c
===================================================================
--- gensupport.c        (revision 162794)
+++ gensupport.c        (working copy)
@@ -1050,7 +1050,7 @@ static const struct std_pred_table std_p
   {"address_operand", true, true, {SUBREG, REG, MEM, PLUS, MINUS, MULT}},
   {"register_operand", false, false, {SUBREG, REG}},
   {"pmode_register_operand", true, false, {SUBREG, REG}},
-  {"scratch_operand", false, false, {SCRATCH, REG}},
+  {"scratch_operand", false, false, {SCRATCH, SUBREG, REG}},
   {"immediate_operand", false, true, {UNKNOWN}},
   {"const_int_operand", false, false, {CONST_INT}},
   {"const_double_operand", false, false, {CONST_INT, CONST_DOUBLE}},


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44031

[Bug target/44031] [4.4/4.5/4.6 Regression] ice in subst_reloads, at reload.c:6327

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44031