[PATCH][GIMPLEFE] Fix for ICE due to undeclared variable

Prasad Ghangal prasad.ghangal@gmail.com
Thu Feb 9 06:00:00 GMT 2017


On 7 February 2017 at 13:40, Richard Biener <richard.guenther@gmail.com> wrote:
> On Mon, Feb 6, 2017 at 7:00 AM, Prasad Ghangal <prasad.ghangal@gmail.com> wrote:
>> On 4 January 2017 at 16:02, Richard Biener <richard.guenther@gmail.com> wrote:
>>> On Wed, Dec 28, 2016 at 7:27 PM, Prasad Ghangal
>>> <prasad.ghangal@gmail.com> wrote:
>>>> Hi,
>>>> The attached patch tries fix ICE due to undeclared variable(s) in the input.
>>>> Successfully bootstrapped on x86_64-pc-linux-gnu, testing is in progress
>>>
>>> Ok.
>>>
>> Can you please commit the patch? I don't have access for that.
>
> Can you share a testcase that broke?  I tried
>

Consider following testcases:

Case 1:
int __GIMPLE foo()
{
  if (a != 2)
    goto bb1;
  else
    goto bb2;

bb1:
  a_1 = 10;
  return a_1;

bb2:
  return 1;
}

gives:

 foo
gcc/test.c: In function ‘foo’:
gcc/test.c:3:7: error: ‘a’ undeclared (first use in this function)
   if (a != 2)
       ^
gcc/test.c:3:7: note: each undeclared identifier is reported only once
for each function it appears in
gcc/test.c:9:3: internal compiler error: in make_ssa_name_fn, at
tree-ssanames.c:268
   a_1 = 10;
   ^~~
0x1199aa0 make_ssa_name_fn(function*, tree_node*, gimple*, unsigned int)
        ../../git_gcc/gcc/tree-ssanames.c:265
0x839e2c c_parser_parse_ssa_name
        ../../git_gcc/gcc/c/gimple-parser.c:675
0x83a5e6 c_parser_gimple_postfix_expression
        ../../git_gcc/gcc/c/gimple-parser.c:845
0x839ac5 c_parser_gimple_unary_expression
        ../../git_gcc/gcc/c/gimple-parser.c:603
0x838544 c_parser_gimple_statement
        ../../git_gcc/gcc/c/gimple-parser.c:271
0x83848e c_parser_gimple_compound_statement
        ../../git_gcc/gcc/c/gimple-parser.c:226
0x837fd2 c_parser_parse_gimple_body(c_parser*)
        ../../git_gcc/gcc/c/gimple-parser.c:92
0x7f7bb5 c_parser_declaration_or_fndef
        ../../git_gcc/gcc/c/c-parser.c:2091
0x7f628a c_parser_external_declaration
        ../../git_gcc/gcc/c/c-parser.c:1468
0x7f5dd3 c_parser_translation_unit
        ../../git_gcc/gcc/c/c-parser.c:1348
0x82a3c4 c_parse_file()
        ../../git_gcc/gcc/c/c-parser.c:18185
0x89c5d9 c_common_parse_file()
        ../../git_gcc/gcc/c-family/c-opts.c:1107
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.



Case 2:

int __GIMPLE ()
main (int argc, char * * argv)
{

  bb_2:
  switch (a) {default: L2; case 1: L0; case 2: L1; }

L0:
  a = 0;
  goto bb_6;

L1:
  a = 3;
  goto L2;

L2:
  return a;

}

 main
gcc/test3.c: In function ‘main’:
gcc/test3.c:6:11: error: ‘a’ undeclared (first use in this function)
   switch (a) {default: L2; case 1: L0; case 2: L1; }
           ^
gcc/test3.c:6:11: note: each undeclared identifier is reported only
once for each function it appears in
gcc/test3.c:6:3: internal compiler error: in gimple_switch_set_index,
at gimple.h:4513
   switch (a) {default: L2; case 1: L0; case 2: L1; }
   ^~~~~~
0xb31385 gimple_switch_set_index
        ../../git_gcc/gcc/gimple.h:4513
0xb33b3f gimple_build_switch_nlabels(unsigned int, tree_node*, tree_node*)
        ../../git_gcc/gcc/gimple.c:757
0xb33b90 gimple_build_switch(tree_node*, tree_node*, vec<tree_node*,
va_heap, vl_ptr>)
        ../../git_gcc/gcc/gimple.c:773
0x83bd94 c_parser_gimple_switch_stmt
        ../../git_gcc/gcc/c/gimple-parser.c:1445
0x83832c c_parser_gimple_compound_statement
        ../../git_gcc/gcc/c/gimple-parser.c:175
0x837fd2 c_parser_parse_gimple_body(c_parser*)
        ../../git_gcc/gcc/c/gimple-parser.c:92
0x7f7bb5 c_parser_declaration_or_fndef
        ../../git_gcc/gcc/c/c-parser.c:2091
0x7f628a c_parser_external_declaration
        ../../git_gcc/gcc/c/c-parser.c:1468
0x7f5dd3 c_parser_translation_unit
        ../../git_gcc/gcc/c/c-parser.c:1348
0x82a3c4 c_parse_file()
        ../../git_gcc/gcc/c/c-parser.c:18185
0x89c5d9 c_common_parse_file()
        ../../git_gcc/gcc/c-family/c-opts.c:1107
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.


Case 3:

void __GIMPLE () foo (int a)
{
bb_2:
  a = *b;

bb_3:
  return;
}

 foo
gcc/test6.c: In function ‘foo’:
gcc/test6.c:5:8: error: ‘b’ undeclared (first use in this function)
   a = *b;
        ^
gcc/test6.c:5:8: note: each undeclared identifier is reported only
once for each function it appears in
gcc/test6.c:5:3: internal compiler error: tree check: expected class
‘type’, have ‘exceptional’ (error_mark) in build_int_cst, at
tree.c:1297
   a = *b;
   ^
0x125cd92 tree_class_check_failed(tree_node const*, tree_code_class,
char const*, int, char const*)
        ../../git_gcc/gcc/tree.c:9866
0x77f8e3 tree_class_check(tree_node*, tree_code_class, char const*,
int, char const*)
        ../../git_gcc/gcc/tree.h:3183
0x123db1e build_int_cst(tree_node*, long)
        ../../git_gcc/gcc/tree.c:1297
0x124b279 build_simple_mem_ref_loc(unsigned int, tree_node*)
        ../../git_gcc/gcc/tree.c:4634
0x8396a8 c_parser_gimple_unary_expression
        ../../git_gcc/gcc/c/gimple-parser.c:565
0x838c9a c_parser_gimple_statement
        ../../git_gcc/gcc/c/gimple-parser.c:339
0x83848e c_parser_gimple_compound_statement
        ../../git_gcc/gcc/c/gimple-parser.c:226
0x837fd2 c_parser_parse_gimple_body(c_parser*)
        ../../git_gcc/gcc/c/gimple-parser.c:92
0x7f7bb5 c_parser_declaration_or_fndef
        ../../git_gcc/gcc/c/c-parser.c:2091
0x7f628a c_parser_external_declaration
        ../../git_gcc/gcc/c/c-parser.c:1468
0x7f5dd3 c_parser_translation_unit
        ../../git_gcc/gcc/c/c-parser.c:1348
0x82a3c4 c_parse_file()
        ../../git_gcc/gcc/c/c-parser.c:18185
0x89c5d9 c_common_parse_file()
        ../../git_gcc/gcc/c-family/c-opts.c:1107
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.


> int __GIMPLE foo(int a)
> {
>   if (t1 != 2)
>     goto bb1;
>   else
>     goto bb2;
>
> bb1:
>   return t1;
>
> bb2:
>   return 1;
> }
>
> and it reports
>
> t.c: In function ‘foo’:
> t.c:3:7: error: ‘t1’ undeclared (first use in this function)
>    if (t1 != 2)
>        ^~
> t.c:3:7: note: each undeclared identifier is reported only once for
> each function it appears in
> t.c:9:10: error: invalid conversion in return statement
>    return t1;
>           ^~
> t.c:1:14: note: declared here
>  int __GIMPLE foo(int a)
>               ^~~
>
> and thus doesn't ICE.
>
> Maybe one of my patches in this area made yours redundant (it doesn't
> apply cleanly anymore as well).

I have rebased and updated the patch.


Thanks,
Prasad

>
> Thanks,
> Richard.
>
>> Thanks,
>> Prasad
>>
>>> Richard.
>>>
>>>>
>>>> Thanks,
>>>> Prasad
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