[llvm-dev] DebugCounter and traps

[David Greene via llvm-dev]

David Greene via llvm-dev <llvm-dev at lists.llvm.org> writes:

> I needed to see what queryAliasing was doing on the "bad"
> transformation.  Unfortunately, DebugCounter has no way to test the
> state of the counter without incrementing it, so I couldn't set a
> conditional breakpoint on the call to queryAliasing.  And conditional
> breakpoints are really slow anyway.

Let me correct that.  It's certainly possible to check the value in a
debugger without incrementing the counter.  But conditional breakpoints
are slow.

It's not possible to *programmatically* check the state of the counter
without changing it, which means one has to do some gymnastics to
remember the counter's value, as the "alternative" example demonstrates.

                            -David