[GVN] Fix last crasher w/non-integral pointers

Same case as for memset and memcpy, but this time for clobbering stores and loads.  We still can't allow coercion to or from non-integrals, regardless of the transform.

Now that I'm done the whole little sequence, it seems apparent that we'd entirely missed reasoning about clobbers in the original GVN support for non-integral pointers.

My appologies, I thought we'd upstreamed all of this, but it turns out we were still carrying a downstream hack which hid all of these issues.  My chanks to Cherry Zhang for helping debug.

llvm-svn: 354407

1 files changed, 18 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/VNCoercion.cpp b/llvm/lib/Transforms/Utils/VNCoercion.cpp
index 1aedce75ca6..181e53e7605 100644
--- a/llvm/lib/Transforms/Utils/VNCoercion.cpp
+++ b/llvm/lib/Transforms/Utils/VNCoercion.cpp
@@ -213,11 +213,22 @@ static int analyzeLoadFromClobberingWrite(Type *LoadTy, Value *LoadPtr,
 /// memdep query of a load that ends up being a clobbering store.
 int analyzeLoadFromClobberingStore(Type *LoadTy, Value *LoadPtr,
                                    StoreInst *DepSI, const DataLayout &DL) {
+  auto *StoredVal = DepSI->getValueOperand();
+  
   // Cannot handle reading from store of first-class aggregate yet.
-  if (DepSI->getValueOperand()->getType()->isStructTy() ||
-      DepSI->getValueOperand()->getType()->isArrayTy())
+  if (StoredVal->getType()->isStructTy() ||
+      StoredVal->getType()->isArrayTy())
     return -1;
 
+  // Don't coerce non-integral pointers to integers or vice versa.
+  if (DL.isNonIntegralPointerType(StoredVal->getType()->getScalarType()) !=
+      DL.isNonIntegralPointerType(LoadTy->getScalarType())) {
+    // Allow casts of zero values to null as a special case
+    auto *CI = dyn_cast<Constant>(StoredVal);
+    if (!CI || !CI->isNullValue())
+      return -1;
+  }
+
   Value *StorePtr = DepSI->getPointerOperand();
   uint64_t StoreSize =
       DL.getTypeSizeInBits(DepSI->getValueOperand()->getType());
@@ -234,6 +245,11 @@ int analyzeLoadFromClobberingLoad(Type *LoadTy, Value *LoadPtr, LoadInst *DepLI,
   if (DepLI->getType()->isStructTy() || DepLI->getType()->isArrayTy())
     return -1;
 
+  // Don't coerce non-integral pointers to integers or vice versa.
+  if (DL.isNonIntegralPointerType(DepLI->getType()->getScalarType()) !=
+      DL.isNonIntegralPointerType(LoadTy->getScalarType()))
+    return -1;
+
   Value *DepPtr = DepLI->getPointerOperand();
   uint64_t DepSize = DL.getTypeSizeInBits(DepLI->getType());
   int R = analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, DepPtr, DepSize, DL);