[CallGraph] New llvm.assume might not show up in GlobalsAA/CallGraph

[jdoerfert]

After we create the CallGraph, we might add a llvm.assume call. They need to be added to the CallGraph, or GlobalsAA thinks the function is side-effect free.

I don't have a small reproducer. I found this because @_X_strcmp in llvm-test-suite/MultiSource/Applications/spiff/compare.c is marked memory(read) even though it contains a (non-trivial) llvm.assume call.

[jdoerfert]

Test case: https://godbolt.org/z/1jbvKPzEn

define internal void @foo(ptr %p) {
  %c = icmp eq ptr %p, null
  br i1 %c, label %err, label %ok
err:
  unreachable
ok:
  ret void
}
define void @bar() {
  call void @foo()
  ret void
}

Run with
-p="require<globals-aa>,simplifycfg,function-attrs"

Results in memory(none) even though there is an llvm.assume (=not good).

[jdoerfert]

Tag (@nikic @fhahn @aeubanks)

[jdoerfert]

Invalid, see discussion here: https://reviews.llvm.org/D155528#4509210