[PATCH] [PATCH][SROA]Also slice the STORE when slicing a LOAD in AllocaSliceRewriter

Jiangning Liu liujiangning1 at gmail.com
Tue Sep 2 03:20:13 PDT 2014

Hi Chandler,

> Once you start slicing up memory accesses, *you break SSA form* and all of
> the analyses that depend on it. I cannot express how strongly I feel this
> is a very bad idea and the wrong direction in the middle end.
What do you mean by "you break SSA form" for the case Hao's patch is
solving? Do you mean some SSA form info could be lost?

The transformation of Hao's patch is to change a single wide store to two
separate narrow stores, but the address of those two narrow stores are
still sequential. For the memory stored here we don't have any SSA
information attached at all, right?

So what SSA form information could be lost? And what optimization could be
affected? Can you give an example?

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