[LLVMdev] Another missed optimization opportunity?

[Caldarale, Charles R]

> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu]
> On Behalf Of Scott Pakin
> Subject: [LLVMdev] Another missed optimization opportunity?

> I'm doing the equivalent of "myarray[5]++" (on an
> "extern int *myarray"), repeated three times:


> I had expected the three increments by 1 to
> be collapsed into a single increment by 3:

> Is there some semantic reason that the increments aren't allowed to be
> combined, or is this a missed optimization opportunity in LLVM?

Is this a potential aliasing effect?  Since myarray is defined as a pointer, not an array, it's theoretically possible that the address therein refers to the same memory location as the pointer itself.

 - Chuck


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