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Propagate nonnull and dereferenceable throught launder
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Authored by Prazek on May 16 2018, 12:41 PM.

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Summary

invariant.group.launder should not stop propagation
of nonnull and dereferenceable, because e.g. we would not be
able to hoist loads speculatively.

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Repository
rL LLVM

Event Timeline

Prazek created this revision.May 16 2018, 12:41 PM
xbolva00 accepted this revision.May 16 2018, 1:21 PM

Looks good

This revision is now accepted and ready to land.May 16 2018, 1:21 PM
hfinkel accepted this revision.May 16 2018, 5:04 PM

I also think that this is fine. Regarding hoisting, will we hoist the intrinsic itself or is further work necessary to enable that?

I also think that this is fine. Regarding hoisting, will we hoist the intrinsic itself or is further work necessary to enable that?

define void @foo(i8* %ptr) {
entry:
  br label %loop
 
loop:
  %x = phi i8 [ 0, %entry ], [ %x.inc, %loop ]
  %p = call i8* @llvm.launder.invariant.group.p0i8(i8* %ptr)
  %val = load i8, i8* %p
  %x.inc = add i8 %x, %val
  br label %loop
}

is not curently hoisted by LICM, so I guess we will have to fix it.
But I have working patch for hoisting invariant.group loads:
https://reviews.llvm.org/D45151

This revision was automatically updated to reflect the committed changes.