RFR(S): 8085932: Fixing bugs in detecting memory alignments in SuperWord

[Vladimir Kozlov]

I forgot to publish updated webrev:

http://cr.openjdk.java.net/~kvn/8085932/webrev.01/

I will push it after Michael's "Vectorized loop unrolling" is reviewed and pushed.

Vladimir

On 6/25/15 5:57 PM, Vladimir Kozlov wrote:
> Okay, this is better.
>
> Thanks,
> Vladimir
>
> On 6/25/15 2:51 PM, Civlin, Jan wrote:
>>
>> Vladimir,
>>
>> Here is the updated patch with trace hidden in a new nested class Trace, that contains all the messages. The Trace
>> class is compiled only in NOT_PRODUCT.
>> Looks much simple now (of course more lines but all outside of the algorithmic part).
>>
>> Thank you,
>>
>> Jan.
>>
>> -----Original Message-----
>> From: Vladimir Kozlov [mailto:vladimir.kozlov at oracle.com]
>> Sent: Thursday, June 18, 2015 5:11 PM
>> To: Civlin, Jan; hotspot-compiler-dev at openjdk.java.net
>> Subject: Re: RFR(S): 8085932: Fixing bugs in detecting memory alignments in SuperWord
>>
>> Thank you, Jan
>>
>> Fixes looks good but it would be nice if you replaced some tracing code
>> with functions calls. In some place the execution code is hard to read
>> because of big tracing code. For example, in
>> SuperWord::memory_alignment() and in SWPointer methods.
>>
>> The one way to do that is to declare trace methods with empty body in
>> product build, for example for SWPointer::scaled_iv_plus_offset() you
>> may have new method declaration (not under #ifdef) in  superword.hpp:
>>
>>     class SWPointer VALUE_OBJ_CLASS_SPEC {
>>
>>       void trace_1_scaled_iv_plus_offset(...) PRODUCT_RETURN;
>>
>> and in superword.cpp you will put the method under ifdef:
>>
>> #ifndef PRODUCT
>>     void trace_1_scaled_iv_plus_offset(...) {
>>       ....
>>     }
>> #endif
>>
>> Then you can simply use it without ifdefs in code:
>>
>>    bool SWPointer::scaled_iv_plus_offset(Node* n) {
>> +  trace_1_scaled_iv_plus_offset(...);
>> +
>>      if (scaled_iv(n)) {
>>
>> Note, macro PRODUCT_RETURN is defined as:
>>
>> #ifdef PRODUCT
>> #define PRODUCT_RETURN  {}
>> #else
>> #define PRODUCT_RETURN  /*next token must be ;*/
>> #endif
>>
>> Thanks,
>> Vladimir
>>
>> On 6/8/15 9:15 AM, Civlin, Jan wrote:
>>> Hi All,
>>>
>>>
>>>    We would like to contribute to Fixing bugs in detecting memory
>>>    alignments in SuperWord.
>>>
>>> The contribution Bug ID: 8085932.
>>>
>>> Please review this patch:
>>>
>>> Bug-id: https://bugs.openjdk.java.net/browse/JDK-8085932
>>>
>>> webrev: http://cr.openjdk.java.net/~kvn/8085932/webrev.00/
>>>
>>>
>>>        *Description**: *Fixing bugs in detecting memory alignments in
>>>        SuperWord
>>>
>>> Fixing bugs in detecting memory alignments in SuperWord:
>>> SWPointer::scaled_iv_plus_offset (fixing here a bug in detection of
>>> "scale"),
>>> SWPointer::offset_plus_k (fixing here a bug in detection of "invariant"),
>>>
>>> Add tracing output to the code that deal with memory alignment. The
>>> following routines are traceable:
>>>
>>> SWPointer::scaled_iv_plus_offset
>>> SWPointer::offset_plus_k
>>> SWPointer::scaled_iv,
>>> WPointer::SWPointer,
>>> SuperWord::memory_alignment
>>>
>>> Tracing is done only for NOT_PRODUCT. Currently tracing is controlled by
>>> VectorizeDebug:
>>>
>>> #ifndef PRODUCT
>>>     if (_phase->C->method() != NULL) {
>>>          _phase->C->method()->has_option_value("VectorizeDebug",
>>> _vector_loop_debug);
>>>     }
>>> #endif
>>>
>>> And VectorizeDebug may take any combination (bitwise OR) of the
>>> following values:
>>> bool is_trace_alignment() { return (_vector_loop_debug & 2) > 0; }
>>> bool is_trace_mem_slice() { return (_vector_loop_debug & 4) > 0; }
>>> bool is_trace_loop() { return (_vector_loop_debug & 8) > 0; }
>>> bool is_trace_adjacent() { return (_vector_loop_debug & 16) > 0; }
>>>
>>