[llvm-commits] [Review Request][PATCH] Refactor BBVectorize: Initialize the MaxIter to

[Hongbin Zheng]

hi hal,

sorry for the trivial mistake.

best regards
ether

On Thu, Apr 5, 2012 at 11:34 PM, Hal Finkel <hfinkel at anl.gov> wrote:
> Ether,
>
> This does not look right because v is changed as v *= 2 in each loop,
> not incremented by one like an iteration count. You'd still need to
> compare v and n separately.
>
> Thanks again,
> Hal
>
> On Thu, 5 Apr 2012 22:36:28 +0800
> Hongbin Zheng <etherzhhb at gmail.com> wrote:
>
>> Hi Hal,
>>
>> This is a rather trivial patch which initialize the "MaxIter" with
>> UINT_MAX, so that later in the loop invoking MaxIter we can replace
>> v <= Config.VectorBits && (!Config.MaxIter || n <= Config.MaxIter)
>>
>> by
>>
>> v <= std::min(Config.VectorBits,Config.MaxIter)
>>
>> Any comment?
>>
>> best regards
>> ether
>>
>> ---
>>  lib/Transforms/Vectorize/BBVectorize.cpp |    8 ++++----
>>  1 files changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/lib/Transforms/Vectorize/BBVectorize.cpp
>> b/lib/Transforms/Vectorize/BBVectorize.cpp
>> index 7672d5c..5a714c8 100644
>> --- a/lib/Transforms/Vectorize/BBVectorize.cpp
>> +++ b/lib/Transforms/Vectorize/BBVectorize.cpp
>> @@ -43,6 +43,7 @@
>>  #include "llvm/Target/TargetData.h"
>>  #include "llvm/Transforms/Vectorize.h"
>>  #include <algorithm>
>> +#include <climits>
>>  #include <map>
>>  using namespace llvm;
>>
>> @@ -63,7 +64,7 @@ VectorBits("bb-vectorize-vector-bits",
>> cl::init(128), cl::Hidden,
>>    cl::desc("The size of the native vector registers"));
>>
>>  static cl::opt<unsigned>
>> -MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden,
>> +MaxIter("bb-vectorize-max-iter", cl::init(UINT_MAX), cl::Hidden,
>>    cl::desc("The maximum number of pairing iterations"));
>>
>>  static cl::opt<unsigned>
>> @@ -295,9 +296,8 @@ namespace {
>>        // Iterate a sufficient number of times to merge types of size
>> 1 bit, // then 2 bits, then 4, etc. up to half of the target vector
>> width of the // target vector register.
>> -      for (unsigned v = 2, n = 1;
>> -           v <= Config.VectorBits && (!Config.MaxIter || n <=
>> Config.MaxIter);
>> -           v *= 2, ++n) {
>> +      for (unsigned v = 2, n = 1, e =
>> std::min(Config.VectorBits,Config.MaxIter);
>> +           v <= e; v *= 2, ++n) {
>>          DEBUG(dbgs() << "BBV: fusing loop #" << n <<
>>                " for " << BB.getName() << " in " <<
>>                BB.getParent()->getName() << "...\n");
>
>
>
> --
> Hal Finkel
> Postdoctoral Appointee
> Leadership Computing Facility
> Argonne National Laboratory