[RS4GC] Lower calls to @llvm.experimental.deoptimize
This changes RS4GC to lower calls to ``@llvm.experimental.deoptimize``
to gc.statepoints wrapping ``__llvm_deoptimize``, and changes
``callsGCLeafFunction`` to recognize ``@llvm.experimental.deoptimize``
as a non GC leaf function.
I've had to hard code the ``"__llvm_deoptimize"`` name in
RewriteStatepointsForGC; since ``TargetLibraryInfo`` is available only
during codegen. This isn't without precedent in the codebase, so I'm
not overtly concerned.
llvm-svn: 264456
diff --git a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
index 0ebc80f..9377c7a 100644
--- a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -1339,6 +1339,26 @@
StatepointID = *SD.StatepointID;
Value *CallTarget = CS.getCalledValue();
+ if (Function *F = dyn_cast<Function>(CallTarget)) {
+ if (F->getIntrinsicID() == Intrinsic::experimental_deoptimize) {
+ // Calls to llvm.experimental.deoptimize are lowered to calls the the
+ // __llvm_deoptimize symbol. We want to resolve this now, since the
+ // verifier does not allow taking the address of an intrinsic function.
+
+ SmallVector<Type *, 8> DomainTy;
+ for (Value *Arg : CallArgs)
+ DomainTy.push_back(Arg->getType());
+ auto *FTy = FunctionType::get(F->getReturnType(), DomainTy,
+ /* isVarArg = */ false);
+
+ // Note: CallTarget can be a bitcast instruction of a symbol if there are
+ // calls to @llvm.experimental.deoptimize with different argument types in
+ // the same module. This is fine -- we assume the frontend knew what it
+ // was doing when generating this kind of IR.
+ CallTarget =
+ F->getParent()->getOrInsertFunction("__llvm_deoptimize", FTy);
+ }
+ }
// Create the statepoint given all the arguments
Instruction *Token = nullptr;
@@ -2320,7 +2340,7 @@
auto NeedsRewrite = [](Instruction &I) {
if (ImmutableCallSite CS = ImmutableCallSite(&I))
- return !callsGCLeafFunction(CS);
+ return !callsGCLeafFunction(CS) && !isStatepoint(CS);
return false;
};