This Patch corrects a problem whereby the optimization to use a faster divide

This Patch corrects a problem whereby the optimization to use a faster divide
instruction (for Intel Atom) was not being done by Clang, because
the type context used by Clang is not the default context.

It fixes the problem by getting the global context types for each div/rem
instruction in order to compare them against the types in the BypassTypeMap.

Tests for this will be done as a separate patch to Clang.

Patch by Tyler Nowicki.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165126 91177308-0d34-0410-b5e6-96231b3b80d8