Recommit r236670: [opaque pointer type] Pass explicit pointer type through GEP constant folding""

Clang regressions were caused by more stringent assertion checking
introduced by this change. Small fix needed to clang has been committed
in r236751.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236752 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed