[PATCH] D18066: Add some shortcuts in Value Propagation for alloca

[Wei Mi via llvm-commits]

Hi Philip,

I tried r267642 using testcases - Groonga and scribus from PR10584.
The result showed r267642 didn't reduce the compile time much. I
looked at r267642 and found a possible reason was that the first
shortcut of nonnull check took effect only when current BB was the
entry BB so we still needed to iterate CFG, right?

scribus13format.cc (scribus):
r266775:                       57.89s
r266775 + r267642:     56.05s
r266775 + patch here: 31.17s

expr.c (Groonga):
r266775:                      226.03s
r266775 + r267642:     225.32s
r266775 + patch here: 44.10s

Thanks,
Wei.

On Tue, Apr 26, 2016 at 5:49 PM, Philip Reames
<listmail at philipreames.com> wrote:
> reames added a comment.
>
> I just checked in a change which may greatly accelerate LVI for the comparison against null case.  Can you check to see if after "267642: [LVI] Reduce compile time by lazily scanning blocks if needed." you're still seeing compile time problems?
>
> The not-constant bypass might still be needed.  I'm not entirely sure.
>
>
> Repository:
>   rL LLVM
>
> http://reviews.llvm.org/D18066
>
>
>