GlobalISel: use correct builder for ConstantExprs.

ConstantExpr instances were emitting code into the current block rather than
the entry block. This meant they didn't necessarily dominate all uses, which is
clearly wrong.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288985 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed