[RS4GC] Re-purpose `normalizeForInvokeSafepoint`; NFC.
`normalizeForInvokeSafepoint` in RewriteStatepointsForGC.cpp, as it is
written today, deals with `gc.relocate` and `gc.result` uses of a
statepoint equally well. This change documents this fact and adds a
test case.
There is no functional change here -- only documentation of existing
functionality.
llvm-svn: 250784
diff --git a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
index a82750b..db8254c 100644
--- a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -1239,12 +1239,12 @@
}
}
-// When inserting gc.relocate calls, we need to ensure there are no uses
-// of the original value between the gc.statepoint and the gc.relocate call.
-// One case which can arise is a phi node starting one of the successor blocks.
-// We also need to be able to insert the gc.relocates only on the path which
-// goes through the statepoint. We might need to split an edge to make this
-// possible.
+// When inserting gc.relocate and gc.result calls, we need to ensure there are
+// no uses of the original value / return value between the gc.statepoint and
+// the gc.relocate / gc.result call. One case which can arise is a phi node
+// starting one of the successor blocks. We also need to be able to insert the
+// gc.relocates only on the path which goes through the statepoint. We might
+// need to split an edge to make this possible.
static BasicBlock *
normalizeForInvokeSafepoint(BasicBlock *BB, BasicBlock *InvokeParent,
DominatorTree &DT) {
@@ -1252,14 +1252,14 @@
if (!BB->getUniquePredecessor())
Ret = SplitBlockPredecessors(BB, InvokeParent, "", &DT);
- // Now that 'ret' has unique predecessor we can safely remove all phi nodes
+ // Now that 'Ret' has unique predecessor we can safely remove all phi nodes
// from it
FoldSingleEntryPHINodes(Ret);
assert(!isa<PHINode>(Ret->begin()) &&
"All PHI nodes should have been removed!");
- // At this point, we can safely insert a gc.relocate as the first instruction
- // in Ret if needed.
+ // At this point, we can safely insert a gc.relocate or gc.result as the first
+ // instruction in Ret if needed.
return Ret;
}