Re: [Bug-apl] svn r849 fails to compile with gcc 6.2 -O3

[Xiao-Yong Jin]

Yes, it remains an error.
The number 255 as I understand comes from
src/SymbolTable.hh:235:class SystemSymTab : public SymbolTableBase<SystemName, 
256 - 1>

> On Jan 18, 2017, at 9:41 AM, Juergen Sauermann <address@hidden> wrote:
> 
> Hi Xiao-Yong,
> 
> I have simplified the loop a little hoping that gcc will get less confused. 
> *SVN 854*.
> 
> If the warning remains then it is definitely bogus.
> 
> Also, I can't really see why iteration 255 should behave differently than all 
> the others.
> 
> /// Jürgen
> 
> 
> On 01/17/2017 05:10 AM, Xiao-Yong Jin wrote:
>> In addition, there is one more warning/error.
>> 
>> g++ -DHAVE_CONFIG_H -I. -I..    -Werror -Wall -I sql 
>> -I/sandbox/pkg/lib/include -I/sandbox/pkg/include  -rdynamic 
>> -Wno-maybe-uninitialized -march=native -O3 -pipe -I/sandbox/pkg/include -MT 
>> apl-SymbolTable.o -MD -MP -MF .deps/apl-SymbolTable.Tpo -c -o 
>> apl-SymbolTable.o `test -f 'SymbolTable.cc' || echo './'`SymbolTable.cc
>> SymbolTable.cc: In member function ‘void SystemSymTab::clear(std::ostream&)’:
>> SymbolTable.cc:499:37: error: iteration 255 invokes undefined behavior 
>> [-Werror=aggressive-loop-optimizations]
>>  SystemName * sym = symbol_table[hash];
>>                                      ^
>> In file included from Assert.hh:24:0,
>>                  from Simple_string.hh:33,
>>                  from CDR_string.hh:24,
>>                  from CDR.hh:24,
>>                  from SymbolTable.cc:24:
>> Common.hh:106:44: note: within this loop
>>  #define loop(v, e) for (ShapeItem v = 0; v < ShapeItem(e); ++v)
>> 
>> SymbolTable.cc:493:4: note: in expansion of macro ‘loop’
>>     loop(hash, SYMBOL_HASH_TABLE_SIZE)   clear_slot(out, hash);
>>     ^~~~
>> cc1plus: all warnings being treated as errors
>> 
>>> On Jan 16, 2017, at 8:05 PM, Xiao-Yong Jin <address@hidden> wrote:
>>> 
>>> Not sure if it's another gcc unrolling bug.
>>> Using gcc 6.2.0
>>> 
>>> g++ -DHAVE_CONFIG_H -I. -I..    -Werror -Wall -I sql 
>>> -I/sandbox/pkg/lib/include -I/sandbox/pkg/include  -rdynamic -march=native 
>>> -O3 -pipe -I/sandbox/pkg/include -MT apl-Bif_F12_SORT.o -MD -MP -MF .deps/ap
>>> l-Bif_F12_SORT.Tpo -c -o apl-Bif_F12_SORT.o `test -f 'Bif_F12_SORT.cc' || 
>>> echo './'`Bif_F12_SORT.cc
>>> In file included from PrintBuffer.hh:28:0,
>>>                 from Cell.hh:27,
>>>                 from Value.hh:30,
>>>                 from Value.icc:24,
>>>                 from NamedObject.hh:25,
>>>                 from Function.hh:27,
>>>                 from PrimitiveFunction.hh:25,
>>>                 from Bif_F12_SORT.hh:25,
>>>                 from Bif_F12_SORT.cc:22:
>>> Shape.hh: In constructor ‘CollatingCache::CollatingCache(const Value&, 
>>> const Cell*, ShapeItem)’:
>>> Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[7]’ may be used 
>>> uninitialized in this function [-Werror=maybe-uninitialized]
>>>         rho[rho_rho++] = len;   volume *= len; }
>>>                                           ^~~
>>> Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[7]’ was 
>>> declared here
>>>          const CollatingCacheEntry entry(uni, A.get_shape());
>>>                                    ^~~~~
>>> In file included from PrintBuffer.hh:28:0,
>>>                 from Cell.hh:27,
>>>                 from Value.hh:30,
>>>                 from Value.icc:24,
>>>                 from NamedObject.hh:25,
>>>                 from Function.hh:27,
>>>                 from PrimitiveFunction.hh:25,
>>>                 from Bif_F12_SORT.hh:25,
>>>                 from Bif_F12_SORT.cc:22:
>>> Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[6]’ may be used 
>>> uninitialized in this function [-Werror=maybe-uninitialized]
>>>         rho[rho_rho++] = len;   volume *= len; }
>>>                                           ^~~
>>> Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[6]’ was 
>>> declared here
>>>          const CollatingCacheEntry entry(uni, A.get_shape());
>>>                                    ^~~~~
>>> In file included from PrintBuffer.hh:28:0,
>>>                 from Cell.hh:27,
>>>                 from Value.hh:30,
>>>                 from Value.icc:24,
>>>                 from NamedObject.hh:25,
>>>                 from Function.hh:27,
>>>                 from PrimitiveFunction.hh:25,
>>>                 from Bif_F12_SORT.hh:25,
>>>                 from Bif_F12_SORT.cc:22:
>>> Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[5]’ may be used 
>>> uninitialized in this function [-Werror=maybe-uninitialized]
>>>         rho[rho_rho++] = len;   volume *= len; }
>>>                                           ^~~
>>> Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[5]’ was 
>>> declared here
>>>          const CollatingCacheEntry entry(uni, A.get_shape());
>>>                                    ^~~~~
>>> In file included from PrintBuffer.hh:28:0,
>>>                 from Cell.hh:27,
>>>                 from Value.hh:30,
>>>                 from Value.icc:24,
>>>                 from NamedObject.hh:25,
>>>                 from Function.hh:27,
>>>                 from PrimitiveFunction.hh:25,
>>>                 from Bif_F12_SORT.hh:25,
>>>                 from Bif_F12_SORT.cc:22:
>>> Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[4]’ may be used 
>>> uninitialized in this function [-Werror=maybe-uninitialized]
>>>         rho[rho_rho++] = len;   volume *= len; }
>>>                                           ^~~
>>> Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[4]’ was 
>>> declared here
>>>          const CollatingCacheEntry entry(uni, A.get_shape());
>>>                                    ^~~~~
>>> In file included from PrintBuffer.hh:28:0,
>>>                 from Cell.hh:27,
>>>                 from Value.hh:30,
>>>                 from Value.icc:24,
>>>                 from NamedObject.hh:25,
>>>                 from Function.hh:27,
>>>                 from PrimitiveFunction.hh:25,
>>>                 from Bif_F12_SORT.hh:25,
>>>                 from Bif_F12_SORT.cc:22:
>>> Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[3]’ may be used 
>>> uninitialized in this function [-Werror=maybe-uninitialized]
>>>         rho[rho_rho++] = len;   volume *= len; }
>>>                                           ^~~
>>> Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[3]’ was 
>>> declared here
>>>          const CollatingCacheEntry entry(uni, A.get_shape());
>>>                                    ^~~~~
>>> In file included from PrintBuffer.hh:28:0,
>>>                 from Cell.hh:27,
>>>                 from Value.hh:30,
>>>                 from Value.icc:24,
>>>                 from NamedObject.hh:25,
>>>                 from Function.hh:27,
>>>                 from PrimitiveFunction.hh:25,
>>>                 from Bif_F12_SORT.hh:25,
>>>                 from Bif_F12_SORT.cc:22:
>>> Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[2]’ may be used 
>>> uninitialized in this function [-Werror=maybe-uninitialized]
>>>         rho[rho_rho++] = len;   volume *= len; }
>>>                                           ^~~
>>> Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[2]’ was 
>>> declared here
>>>          const CollatingCacheEntry entry(uni, A.get_shape());
>>>                                    ^~~~~
>>> In file included from PrintBuffer.hh:28:0,
>>>                 from Cell.hh:27,
>>>                 from Value.hh:30,
>>>                 from Value.icc:24,
>>>                 from NamedObject.hh:25,
>>>                 from Function.hh:27,
>>>                 from PrimitiveFunction.hh:25,
>>>                 from Bif_F12_SORT.hh:25,
>>>                 from Bif_F12_SORT.cc:22:
>>> Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[1]’ may be used 
>>> uninitialized in this function [-Werror=maybe-uninitialized]
>>>         rho[rho_rho++] = len;   volume *= len; }
>>>                                           ^~~
>>> Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[1]’ was 
>>> declared here
>>>          const CollatingCacheEntry entry(uni, A.get_shape());
>>>                                    ^~~~~
>>> cc1plus: all warnings being treated as errors
>>> make[3]: *** [apl-Bif_F12_SORT.o] Error 1
>> 
>> 
>