Fix vectorization remarks.

This patch changes the vectorization remarks to also inform when
vectorization is possible but not beneficial.

Added tests to exercise some loop remarks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207574 91177308-0d34-0410-b5e6-96231b3b80d8
[Windows] Fix assertion failure when passing 'nul' in input to clang.

Before this patch, if 'nul' was passed in input to clang, function
getStatus() (in Path.inc) always returned an instance of file_status with
field 'nFileSizeHigh' and 'nFileSizeLow' left uninitialized.

This was causing the triggering of an assertion failure in MemoryBuffer.cpp due
to an invalid FileSize for device 'nul'.

This patch fixes the assertion failure modifying the constructors of class
file_status (in llvm/Support/FileSystem.h) so that every field of the class
gets initialized to zero by default.

A clang test will be submitted on a separate patch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207575 91177308-0d34-0410-b5e6-96231b3b80d8
Two fixes to the vpermilvar optimization.

The instcomine logic to handle vpermilvar's pd and 256 variants was incorrect.
The _256 variants have indexes into the individual 128 bit lanes and in all
cases it also has to mask out unused bits.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207577 91177308-0d34-0410-b5e6-96231b3b80d8