search for: storiung

...global value" is a constant. So I guess it's ok to forward that constant value to the use even though the store does not dominate it (as you say, undef can be anything). All right, this makes sense to me. But why is it any different if the stored value is from an instruction? We're storiung some value into an alloca (under a condition in this case) and the alloca later gets used in a place not dominated by the store (outside the condition in this case). Who cares where the value being stored came from? -Dave

On Fri, Sep 19, 2008 at 11:08 AM, David Greene <dag at cray.com> wrote: > \Why is this only prevented when NOT storing > to global values? It's not a question of storing *to* a global value, but storing a global value into the alloca. If there's only a single store to an alloca, there are only two possible values that can be extracted from the alloca: the value stored, and

I have a question about PromoteMem2Reg::RewriteSingleStoreAlloca. Specifically, this bit of code: // If the store dominates the block and if we haven't processed it yet, // do so now. We can't handle the case where the store doesn't dominate a // block because there may be a path between the store and the use, but we // may need to insert phi nodes to handle dominance