This lifts a restriction on DILocation::getMergedLocation(), allowing it
to create merged locations for instructions other than calls.
Instruction::applyMergedLocation() now defaults to creating merged
locations for all instructions.
The default behavior of getMergedLocation() is unchanged: callers which
invoke it directly are unaffected.
This change will enable a follow-up Mem2Reg fix which improves crash
reporting.
Differential Revision: https://reviews.llvm.org/D45396
llvm-svn: 329955
