1 files changed, 92 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/Analysis/Local.cpp b/contrib/llvm-project/llvm/lib/Analysis/Local.cpp
new file mode 100644
index 000000000000..5d558de516d3
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/Analysis/Local.cpp
@@ -0,0 +1,92 @@
+//===- Local.cpp - Functions to perform local transformations -------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This family of functions perform various local transformations to the
+// program.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/Utils/Local.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
+#include "llvm/IR/IRBuilder.h"
+
+using namespace llvm;
+
+Value *llvm::emitGEPOffset(IRBuilderBase *Builder, const DataLayout &DL,
+                           User *GEP, bool NoAssumptions) {
+  GEPOperator *GEPOp = cast<GEPOperator>(GEP);
+  Type *IntIdxTy = DL.getIndexType(GEP->getType());
+  Value *Result = nullptr;
+
+  // If the GEP is inbounds, we know that none of the addressing operations will
+  // overflow in a signed sense.
+  bool isInBounds = GEPOp->isInBounds() && !NoAssumptions;
+
+  // Build a mask for high order bits.
+  unsigned IntPtrWidth = IntIdxTy->getScalarType()->getIntegerBitWidth();
+  uint64_t PtrSizeMask =
+      std::numeric_limits<uint64_t>::max() >> (64 - IntPtrWidth);
+
+  gep_type_iterator GTI = gep_type_begin(GEP);
+  for (User::op_iterator i = GEP->op_begin() + 1, e = GEP->op_end(); i != e;
+       ++i, ++GTI) {
+    Value *Op = *i;
+    uint64_t Size = DL.getTypeAllocSize(GTI.getIndexedType()) & PtrSizeMask;
+    Value *Offset;
+    if (Constant *OpC = dyn_cast<Constant>(Op)) {
+      if (OpC->isZeroValue())
+        continue;
+
+      // Handle a struct index, which adds its field offset to the pointer.
+      if (StructType *STy = GTI.getStructTypeOrNull()) {
+        uint64_t OpValue = OpC->getUniqueInteger().getZExtValue();
+        Size = DL.getStructLayout(STy)->getElementOffset(OpValue);
+        if (!Size)
+          continue;
+
+        Offset = ConstantInt::get(IntIdxTy, Size);
+      } else {
+        // Splat the constant if needed.
+        if (IntIdxTy->isVectorTy() && !OpC->getType()->isVectorTy())
+          OpC = ConstantVector::getSplat(
+              cast<VectorType>(IntIdxTy)->getElementCount(), OpC);
+
+        Constant *Scale = ConstantInt::get(IntIdxTy, Size);
+        Constant *OC =
+            ConstantExpr::getIntegerCast(OpC, IntIdxTy, true /*SExt*/);
+        Offset =
+            ConstantExpr::getMul(OC, Scale, false /*NUW*/, isInBounds /*NSW*/);
+      }
+    } else {
+      // Splat the index if needed.
+      if (IntIdxTy->isVectorTy() && !Op->getType()->isVectorTy())
+        Op = Builder->CreateVectorSplat(
+            cast<FixedVectorType>(IntIdxTy)->getNumElements(), Op);
+
+      // Convert to correct type.
+      if (Op->getType() != IntIdxTy)
+        Op = Builder->CreateIntCast(Op, IntIdxTy, true, Op->getName() + ".c");
+      if (Size != 1) {
+        // We'll let instcombine(mul) convert this to a shl if possible.
+        Op = Builder->CreateMul(Op, ConstantInt::get(IntIdxTy, Size),
+                                GEP->getName() + ".idx", false /*NUW*/,
+                                isInBounds /*NSW*/);
+      }
+      Offset = Op;
+    }
+
+    if (Result)
+      Result = Builder->CreateAdd(Result, Offset, GEP->getName() + ".offs",
+                                  false /*NUW*/, isInBounds /*NSW*/);
+    else
+      Result = Offset;
+  }
+  return Result ? Result : Constant::getNullValue(IntIdxTy);
+}