[Bug tree-optimization/18291] New: 4.0: ICE in merge_alias_info

[gcc-bugzilla at gcc dot gnu dot org]

g++ 4.0 gives an ICE compiling the source below with -O1:

$ ./cc1plus -quiet -O1 x.cc
x.cc: In function 'void writeDigi()':
x.cc:10: internal compiler error: in merge_alias_info, at tree-ssa-copy.c:217
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.
$

It's crashing at the abort() here:

212       if (new_ptr_info->name_mem_tag == NULL_TREE)
213         memcpy (new_ptr_info, orig_ptr_info, sizeof (*new_ptr_info));
214       else if (orig_ptr_info->name_mem_tag == NULL_TREE)
215         memcpy (orig_ptr_info, new_ptr_info, sizeof (*orig_ptr_info));
216       else if (orig_ptr_info->name_mem_tag != new_ptr_info->name_mem_tag)
217         abort ();

Here are the values that are being compared:

(gdb) p *orig_ptr_info
$5 = {pt_anything = 0, pt_malloc = 0, value_escapes_p = 0,
  is_dereferenced = 1, pt_global_mem = 0, pt_vars = 0x400b18a0,
  name_mem_tag = 0x400baef4}
(gdb) p *new_ptr_info
$6 = {pt_anything = 0, pt_malloc = 0, value_escapes_p = 0,
  is_dereferenced = 1, pt_global_mem = 0, pt_vars = 0x400b1880,
  name_mem_tag = 0x400bae80}
(gdb) call debug_tree( orig_ptr_info->name_mem_tag)
 <var_decl 0x400baef4 NMT.4
    type <integer_type 0x4002a4fc int public SI
        size <integer_cst 0x400223d8 constant invariant 32>
        unit size <integer_cst 0x40022168 constant invariant 4>
        align 32 symtab 0 alias set -1 precision 32 min <integer_cst 0x40022390 -2147483648> max <integer_cst 0x400223a8 2147483647>
        pointer_to_this <pointer_type 0x40038ef4>>
    addressable used ignored SI file x.cc line 10 size <integer_cst 0x400223d8 32> unit size <integer_cst 0x40022168 4>
    align 32 context <function_decl 0x400b8a6c writeDigi>>
(gdb) call debug_tree( new_ptr_info->name_mem_tag)
 <var_decl 0x400bae80 NMT.3
    type <integer_type 0x4002a4fc int public SI
        size <integer_cst 0x400223d8 constant invariant 32>
        unit size <integer_cst 0x40022168 constant invariant 4>
        align 32 symtab 0 alias set -1 precision 32 min <integer_cst 0x40022390 -2147483648> max <integer_cst 0x400223a8 2147483647>
        pointer_to_this <pointer_type 0x40038ef4>>
    addressable used ignored SI file x.cc line 10 size <integer_cst 0x400223d8 32> unit size <integer_cst 0x40022168 4>
    align 32 context <function_decl 0x400b8a6c writeDigi>>

Environment:
System: Linux karma 2.6.8.1 #20 Mon Sep 13 23:48:47 EDT 2004 i686 i686 i386 GNU/Linux
Architecture: i686

	<machine, os, target, libraries (multiple lines)>
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: /home/sss/gcc/gcc/configure --prefix=/usr/local/gcc --enable-threads=posix --enable-long-long --enable-languages=c,c++,f95

How-To-Repeat:


Compile with -O1:
-------------------------------------------------

struct C
{
  int size() const  { return 0;}
};

int foo (int);

void writeDigi()
{
  C strErgC;
  int  mcdigi ;
  int* pmcdigi = &mcdigi ;
  int  mcdigi_crosstalk ;
  if ( foo(0) )
    pmcdigi = &mcdigi_crosstalk;

  int mcdigi_elec_noise ;
  if ( strErgC.size() > 0 )
  {
    foo(*pmcdigi );
    pmcdigi = &mcdigi_elec_noise;
  }
  foo(*pmcdigi);
}

-------------------------------------------------
------- Additional Comments From snyder at fnal dot gov  2004-11-03 20:43 -------
Fix:
	<how to correct or work around the problem, if known (multiple lines)>

-- 
           Summary: 4.0: ICE in merge_alias_info
           Product: gcc
           Version: 0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: snyder at fnal dot gov
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18291