[InstCombine] Folding of a binop with RHS const should merge the debug locations

If all the operands to a phi node are a binop with a RHS constant, instcombine
will try to pull them through the phi node, combining them into a single
operation. When it does this, the debug location of the new op should be the
merged debug locations of the phi node arguments.

Patch 7 of 8 for D26256.  Folding of a binop with RHS constant.

Differential Revision: https://reviews.llvm.org/D26256


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289699 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed