[LLVMdev] Load/store grouping and AntiDepBreaker

[Francois Pichet]

Hi,

On my target, grouping load/store together almost always gives better
performance even if it increases register pressure.

Basically I want code like this:
  load r1, addr1
  instr r1, x, y
  store addr2 r1
  load r1, addr3
  instr r1, x, y
  store addr4 r1

to be rewritten as:
  load r1, addr1
  load r2, addr3
  instr r1, x, y
  instr r2, x, y
  store addr2, r1
  store addr4, r2

I enabled the AggressiveAntiDepBreaker pass and it actually works for a lot
of case but not always.
What would be the best way to guarantee that load/store are grouped and
executed together?

Thanks,
Francois Pichet, Octasic.
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