[PATCH] [GVN] Eliminate redundant loads whose addresses are dependent on the result of a select instruction.

[Chad Rosier]

I've abandoned this patch (originally abandoned on March 16th).  Overall, I saw no significant performance improvements across SPEC2K/SPEC2K6 and after further testing there was one significant regression (i.e., 6% on spec2000/vpr), which was the workload I was targeting.  While the patch does remove the redundant load, that redundancy was replaced by another set of redundant instructions, fcmp/csel.  IIRC, csel instructions are bad for A57 devices in general.

I agree that a more general solution should be considered and if the new PRE pass can enable that solution, I'm in no rush to push this patch forward.

Regardless, I do appreciate everyones feedback!


http://reviews.llvm.org/D8120

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