In the below scenario, we must be able to skip the a DBG_VALUE instruction and

In the below scenario, we must be able to skip the a DBG_VALUE instruction and
remove the dead store.

%vreg0<def> = L2_loadri_io <fi#15>, 0; mem:LD4[%dataF](align=4)
DBG_VALUE %vreg0, %noreg, !"dataF", <!184>; IntRegs:%vreg0
S2_storeri_io <fi#15>, 0, %vreg0; mem:ST4[%dataF]

In reality, this kind of stores are eliminated before Stack Slot Coloring pass,
possibly in instruction lowering

Differential Revision: https://reviews.llvm.org/D26616

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291455 91177308-0d34-0410-b5e6-96231b3b80d8