[llvm-commits] [llvm] r95266 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineCalls.cpp test/Transforms/InstCombine/objsize.ll

[Duncan Sands]

Hi Eric,

> If we're dealing with a zero-length array, don't lower to any
> particular size, we just don't know what the length is yet.

...

> + at window = external global [0 x i8]

I think this is wrong - the problem isn't due to a zero length array, it's
due to the global being a declaration rather than a definition (i.e. not having
an initializer).  The type of a declaration doesn't tell you anything about the
size of the actual object (which is defined in some other object file).   For
example, suppose this was:

   @window = external global i32

and then in some other file you have the definition:

   @window = global i8 0

This is perfectly legal, and shows that trying to determine the "object size"
based only on a declaration is hopeless.

Ciao,

Duncan.