[llvm-commits] [llvm] r48999 - /llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp

[Evan Cheng]

It looks right to me:

   // If the starting point was specifiy, use it
   if (start) {
     QI = start;
     blockBegin = start->getParent()->begin();
   // If the starting point wasn't specified, but the block was, use it
   } else if (!start && block) {
     QI = block->end();
     blockBegin = block->begin();
   }

   // Walk backwards through the block, looking for dependencies
   while (QI != blockBegin) {
     --QI;

QI is the iterator. Seems to me blockBegin really should point to the  
start of the block.

Evan

On Mar 31, 2008, at 11:12 PM, Owen Anderson wrote:

> Dan,
>
> I don't think this is right.  MemDep walks backwards through the  
> block to find dependencies, so it needs to start at the end of the  
> block.
>
> --Owen
>
> On Mar 31, 2008, at 5:08 PM, Dan Gohman wrote:
>
>> Author: djg
>> Date: Mon Mar 31 17:08:00 2008
>> New Revision: 48999
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=48999&view=rev
>> Log:
>> Set blockBegin to point to the beginning of the block,
>> not the end.
>>
>> Modified:
>>   llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
>>
>> Modified: llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp?rev=48999&r1=48998&r2=48999&view=diff
>>
>> = 
>> = 
>> = 
>> = 
>> = 
>> = 
>> = 
>> = 
>> = 
>> =====================================================================
>> --- llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp (original)
>> +++ llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp Mon Mar 31  
>> 17:08:00 2008
>> @@ -99,11 +99,11 @@
>>  // If the starting point was specifiy, use it
>>  if (start) {
>>    QI = start;
>> -    blockBegin = start->getParent()->end();
>> +    blockBegin = start->getParent()->begin();
>>  // If the starting point wasn't specified, but the block was, use it
>>  } else if (!start && block) {
>>    QI = block->end();
>> -    blockBegin = block->end();
>> +    blockBegin = block->begin();
>>  }
>>
>>  // Walk backwards through the block, looking for dependencies
>>
>>
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