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6f93f61542
Summary:
Readnone attribute would cause CSE of two barriers with
the same argument, which is invalid by example:
struct Base {
virtual int foo() { return 42; }
};
struct Derived1 : Base {
int foo() override { return 50; }
};
struct Derived2 : Base {
int foo() override { return 100; }
};
void foo() {
Base *x = new Base{};
new (x) Derived1{};
int a = std::launder(x)->foo();
new (x) Derived2{};
int b = std::launder(x)->foo();
}
Here 2 calls of std::launder will produce @llvm.invariant.group.barrier,
which would be merged into one call, causing devirtualization
to devirtualize second call into Derived1::foo() instead of
Derived2::foo()
Reviewers: chandlerc, dberlin, hfinkel
Subscribers: llvm-commits, rsmith, amharc
Differential Revision: https://reviews.llvm.org/D31531
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300101 91177308-0d34-0410-b5e6-96231b3b80d8
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| .. | ||
| assume.ll | ||
| atomic-clobber.ll | ||
| basicaa-memcpy.ll | ||
| constant-memory.ll | ||
| cyclicphi.ll | ||
| forward-unreachable.ll | ||
| function-clobber.ll | ||
| function-mem-attrs.ll | ||
| invariant-groups.ll | ||
| lifetime-simple.ll | ||
| load-invariant.ll | ||
| many-dom-backedge.ll | ||
| many-doms.ll | ||
| multi-edges.ll | ||
| multiple-backedges-hal.ll | ||
| multiple-locations.ll | ||
| no-disconnected.ll | ||
| optimize-use.ll | ||
| phi-translation.ll | ||
| pr28880.ll | ||
| ptr-const-mem.ll | ||
| volatile-clobber.ll | ||