[DependenceAnalysis] Fix for PR21585: collectUpperBound triggers asserts

collectUpperBound hits an assertion when the back edge count is wider then the desired type.

If that happens, truncate the backedge count.

Patch by Philip Pfaffe!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237439 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed