[LLVMdev] How to test isDereferenceablePointer?

[Ramkumar Ramachandra]

I'm have a
    [PATCH] isDereferenceablePointer: look through gc.relocates

and I want to know how to test this patch. So far, I've found one
candiate: speculative execution in SimplifyCFG
(test/Transforms/SimplifyCFG/SpeculativeExec.ll). However, it's
somewhat involved to show that SimplifyCFG does kick in for
gc.relocate. Is there a better way to directly test it?

Signed-off-by: Ramkumar Ramachandra <artagnon at gmail.com>
---
 lib/IR/Value.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/lib/IR/Value.cpp b/lib/IR/Value.cpp
index 5f7e258..aa701d5 100644
--- a/lib/IR/Value.cpp
+++ b/lib/IR/Value.cpp
@@ -23,8 +23,10 @@
 #include "llvm/IR/GetElementPtrTypeIterator.h"
 #include "llvm/IR/InstrTypes.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Operator.h"
+#include "llvm/IR/Statepoint.h"
 #include "llvm/IR/ValueHandle.h"
 #include "llvm/IR/ValueSymbolTable.h"
 #include "llvm/Support/Debug.h"
@@ -570,6 +572,13 @@ static bool isDereferenceablePointer(const Value *V, const DataLayout *DL,
     return true;
   }
 
+  // For gc.relocate, look through relocations
+  if (const IntrinsicInst *I = dyn_cast<IntrinsicInst>(V))
+    if (I->getIntrinsicID() == Intrinsic::experimental_gc_relocate) {
+      GCRelocateOperands RelocateInst(I);
+      return isDereferenceablePointer(RelocateInst.derivedPtr(), DL, Visited);
+    }
+
   if (const AddrSpaceCastInst *ASC = dyn_cast<AddrSpaceCastInst>(V))
     return isDereferenceablePointer(ASC->getOperand(0), DL, Visited);
 
-- 
2.2.1