No need to check for non-existing std::map elements

It seems we added guards to check for non-existing std::map elements to make
sure they are default constructed before first accessed. Besides, the code
being wrong because of checking Context.NonAffineAccesses[BasePointer].size()
instead of Context.cound(BasePointer), such a check is also not necessary
as std::map takes care of this already.

From the std::map documentation:

"If k does not match the key of any element in the container, the function
inserts a new element with that key and returns a reference to its mapped value.
Notice that this always increases the container size by one, even if no mapped
value is assigned to the element (the element is constructed using its default
constructor)."

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@217506 91177308-0d34-0410-b5e6-96231b3b80d8
Use "const auto &" in range based for loops

This previous code added in r216842 most likely created unnecessary copies.

Reported-by: Duncan P. N. Exon Smith  <dexonsmith@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@217507 91177308-0d34-0410-b5e6-96231b3b80d8
[Refactor] Cleanup isl code generation

Summary:
  + Refactor the runtime check (RTC) build function
  + Added helper function to create an PollyIRBuilder
  + Change the simplify region function to create not
    only unique entry and exit edges but also enfore that
    the entry edge is unconditional
  + Cleaned the IslCodeGeneration runOnScop function:
      - less post-creation changes of the created IR
  + Adjusted and added test cases

Reviewers: grosser, sebpop, simbuerg, dpeixott

Subscribers: llvm-commits, #polly

Differential Revision: http://reviews.llvm.org/D5076



git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@217508 91177308-0d34-0410-b5e6-96231b3b80d8