[PATCH] ADCE: Remove debug info intrinsics in dead scopes

[Adrian Prantl via llvm-commits]

> On Mar 29, 2016, at 12:34 PM, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
> 
> During ADCE, track which debug info scopes still have live references
> from the code, and delete debug info intrinsics for the dead ones.
> 
> These intrinsics describe the locations of variables (in registers or
> stack slots).  If there's no code left corresponding to a variable's
> scope, then there's no way to reference the variable in the debugger and
> it doesn't matter what its value is.
> 
> I add a DEBUG printout when the described location in an SSA register,
> in case it helps some trying to track down why locations get lost.
> However, we still delete these; the root problem is that the scope
> itself isn't attached to any real code.

Thanks!

> 
> <0001-ADCE-Remove-debug-info-intrinsics-in-dead-scopes.patch>

One review comment: There should also be a testcase where the scope is in an inlined function.

-- adrian