[PATCH] A new HeapToStack allocation promotion pass

[Hal Finkel]

----- Original Message -----
> 
> 
> ================
> Comment at: lib/Transforms/Scalar/HeapToStack.cpp:275
> @@ +274,3 @@
> +
> +    if (VerifiedMallocs.count((Instruction *) FAddr)) {
> +      DEBUG(dbgs() << "H2S: malloc " << *FAddr <<
> ----------------
> Seems odd to use c-style casts?

FAddr might not be an instruction, but it probably is. I could write:

  if (isa<Instruction>(FAddr) && VerifiedMallocs.count(cast<Instruction>(FAddr)))

or even

  if (VerifiedMallocs.count(dyn_cast<Instruction>(FAddr)))

but both of those pessimize the common case. Pointers to non-instruction will never be in the map.

It is just a micro-optimization (which happens to lead to fewer source-code characters). I'm fine with removing it for clarity.

Thanks,
Hal

> 
> 
> http://llvm-reviews.chandlerc.com/D1745
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory