DebugLocLists with no entries: any idea how to generate a testcase?

[Duncan P. N. Exon Smith]

I've noticed there are debug loc lists with no entries sometimes
in my heap profiling workload (a linker dump of `-flto -g`).  It
seems to happen when *all* the locations correspond to `%noreg`.

This patch adds an assertion (which fires on my big workload,
but not in any of our tests), and adds a likely fix that's
commented out.

Does anyone know how to generate this kind of thing, or should I
just start compiling things to see if I can make it happen on my
own?  (I've tried reducing my workload, but I'm having trouble
getting very far with it.)

-------------- next part --------------
A non-text attachment was scrubbed...
Name: empty-debug-loc-lists.patch
Type: application/octet-stream
Size: 1469 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150527/e8764847/attachment.obj>