lxfind added inline comments.
================
Comment at: llvm/include/llvm/IR/Intrinsics.td:1309
+// Intrinsic to obtain the address of a thread_local variable.
+def int_threadlocal : Intrinsic<[llvm_ptr_ty], [llvm_ptr_ty]>;
+
----------------
hoy wrote:
> lxfind wrote:
> > hoy wrote:
> > > hoy wrote:
> > > > With the intrinsic, can TLS variable reference in the same coroutine or
> > > > regular routine be DCE-ed anymore?
> > > Sorry, I meant CSE-ed.
> > Since the intrinsics does not have readnone attribute, it won't be CSE-ed
> > before CoroSplit.
> > However after CoroSplit, it will be lowered back to the direct reference of
> > the TLS, and will be CSE-ed by latter passes.
> > I can add a test function to demonstrate that too.
> Sounds good. Can you please point out what optimization passes CSE-ed tls
> reference without this implementation? I'm wondering if those optimizations
> can be postponed to after CoroSplit.
To clarify, it wasn't just CSE that would merge the references of the same TLS.
For instance, without this patch, a reference to "tls_variable" will just be
"@tls_variable". For code like this:
@tls_variable = internal thread_local global i32 0, align 4
define i32* @foo(){
ret i32* @tls_variable
}
define void @bar() {
%tls1 = call i32* @foo()
..coro.suspend..
%tls2 = call i32* @foo()
%cond = icmp eq i32* %tls1, %tls2
}
When foo() is inlined into bar(), all uses of %tls1 will be replaced with
@tls_variable.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D92661/new/
https://reviews.llvm.org/D92661
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