[DAG] Move BaseIndexOffset into separate Libarary. NFC.

Move BaseIndexOffset analysis out of DAGCombiner for use in other
files.

llvm-svn: 305921

3 files changed, 97 insertions, 114 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt b/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt
index a668ddb7389..ae9c5adb039 100644
--- a/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt
+++ b/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt
@@ -17,6 +17,7 @@ add_llvm_library(LLVMSelectionDAG
   ScheduleDAGVLIW.cpp
   SelectionDAGBuilder.cpp
   SelectionDAG.cpp
+  SelectionDAGAddressAnalysis.cpp
   SelectionDAGDumper.cpp
   SelectionDAGISel.cpp
   SelectionDAGPrinter.cpp
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 0e092927974..14a722a59e8 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -25,6 +25,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/SelectionDAGAddressAnalysis.h"
 #include "llvm/CodeGen/SelectionDAGTargetInfo.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DerivedTypes.h"
@@ -4695,120 +4696,6 @@ SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, const SDLoc &DL) {
 }
 
 namespace {
-/// Helper struct to parse and store a memory address as base + index + offset.
-/// We ignore sign extensions when it is safe to do so.
-/// The following two expressions are not equivalent. To differentiate we need
-/// to store whether there was a sign extension involved in the index
-/// computation.
-///  (load (i64 add (i64 copyfromreg %c)
-///                 (i64 signextend (add (i8 load %index)
-///                                      (i8 1))))
-/// vs
-///
-/// (load (i64 add (i64 copyfromreg %c)
-///                (i64 signextend (i32 add (i32 signextend (i8 load %index))
-///                                         (i32 1)))))
-class BaseIndexOffset {
-private:
-  SDValue Base;
-  SDValue Index;
-  int64_t Offset;
-  bool IsIndexSignExt;
-
-public:
-  BaseIndexOffset() : Offset(0), IsIndexSignExt(false) {}
-
-  BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset,
-                  bool IsIndexSignExt) :
-    Base(Base), Index(Index), Offset(Offset), IsIndexSignExt(IsIndexSignExt) {}
-
-  SDValue getBase() { return Base; }
-  SDValue getIndex() { return Index; }
-
-  bool equalBaseIndex(BaseIndexOffset &Other, const SelectionDAG &DAG) {
-    int64_t Off;
-    return equalBaseIndex(Other, DAG, Off);
-  }
-
-  bool equalBaseIndex(BaseIndexOffset &Other, const SelectionDAG &DAG,
-                      int64_t &Off) {
-    // Obvious equivalent
-    Off = Other.Offset - Offset;
-    if (Other.Base == Base && Other.Index == Index &&
-        Other.IsIndexSignExt == IsIndexSignExt)
-      return true;
-
-    // Match GlobalAddresses
-    if (Index == Other.Index)
-      if (GlobalAddressSDNode *A = dyn_cast<GlobalAddressSDNode>(Base))
-        if (GlobalAddressSDNode *B = dyn_cast<GlobalAddressSDNode>(Other.Base))
-          if (A->getGlobal() == B->getGlobal()) {
-            Off += B->getOffset() - A->getOffset();
-            return true;
-          }
-
-    // TODO: we should be able to add FrameIndex analysis improvements here.
-
-    return false;
-  }
-
-  /// Parses tree in Ptr for base, index, offset addresses.
-  static BaseIndexOffset match(SDValue Ptr) {
-    // (((B + I*M) + c)) + c ...
-    SDValue Base = Ptr;
-    SDValue Index = SDValue();
-    int64_t Offset = 0;
-    bool IsIndexSignExt = false;
-
-    //Consume constant adds
-    while (Base->getOpcode() == ISD::ADD &&
-           isa<ConstantSDNode>(Base->getOperand(1))) {
-      int64_t POffset = cast<ConstantSDNode>(Base->getOperand(1))->getSExtValue();
-      Offset += POffset;
-      Base = Base->getOperand(0);
-    }
-
-    if (Base->getOpcode() == ISD::ADD) {
-      // TODO: The following code appears to be needless as it just
-      //       bails on some Ptrs early, reducing the cases where we
-      //       find equivalence. We should be able to remove this.
-      // Inside a loop the current BASE pointer is calculated using an ADD and a
-      // MUL instruction. In this case Base is the actual BASE pointer.
-      // (i64 add (i64 %array_ptr)
-      //          (i64 mul (i64 %induction_var)
-      //                   (i64 %element_size)))
-      if (Base->getOperand(1)->getOpcode() == ISD::MUL)
-        return BaseIndexOffset(Base, Index, Offset, IsIndexSignExt);
-
-      // Look at Base + Index + Offset cases.
-      Index   = Base->getOperand(1);
-      SDValue PotentialBase = Base->getOperand(0);
-
-      // Skip signextends.
-      if (Index->getOpcode() == ISD::SIGN_EXTEND) {
-        Index = Index->getOperand(0);
-        IsIndexSignExt = true;
-      }
-
-      // Check if Index Offset pattern
-      if (Index->getOpcode() != ISD::ADD ||
-          !isa<ConstantSDNode>(Index->getOperand(1)))
-        return BaseIndexOffset(PotentialBase, Index, Offset, IsIndexSignExt);
-
-      Offset += cast<ConstantSDNode>(Index->getOperand(1))->getSExtValue();
-      Index = Index->getOperand(0);
-      if (Index->getOpcode() == ISD::SIGN_EXTEND) {
-        Index = Index->getOperand(0);
-        IsIndexSignExt = true;
-      } else IsIndexSignExt = false;
-      Base = PotentialBase;
-    }
-    return BaseIndexOffset(Base, Index, Offset, IsIndexSignExt);
-  }
-};
-} // namespace
-
-namespace {
 /// Represents known origin of an individual byte in load combine pattern. The
 /// value of the byte is either constant zero or comes from memory.
 struct ByteProvider {
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp
new file mode 100644
index 00000000000..d2e0dbbf88e
--- /dev/null
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp
@@ -0,0 +1,95 @@
+//===-- llvm/CodeGen/SelectionDAGAddressAnalysis.cpp ------- DAG Address
+//Analysis ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+
+#include "llvm/CodeGen/SelectionDAGAddressAnalysis.h"
+#include "llvm/CodeGen/ISDOpcodes.h"
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/SelectionDAGNodes.h"
+
+namespace llvm {
+
+bool BaseIndexOffset::equalBaseIndex(BaseIndexOffset &Other,
+                                     const SelectionDAG &DAG, int64_t &Off) {
+  // Obvious equivalent
+  Off = Other.Offset - Offset;
+  if (Other.Base == Base && Other.Index == Index &&
+      Other.IsIndexSignExt == IsIndexSignExt)
+    return true;
+
+  // Match GlobalAddresses
+  if (Index == Other.Index)
+    if (GlobalAddressSDNode *A = dyn_cast<GlobalAddressSDNode>(Base))
+      if (GlobalAddressSDNode *B = dyn_cast<GlobalAddressSDNode>(Other.Base))
+        if (A->getGlobal() == B->getGlobal()) {
+          Off += B->getOffset() - A->getOffset();
+          return true;
+        }
+
+  // TODO: we should be able to add FrameIndex analysis improvements here.
+
+  return false;
+}
+
+/// Parses tree in Ptr for base, index, offset addresses.
+BaseIndexOffset BaseIndexOffset::match(SDValue Ptr) {
+  // (((B + I*M) + c)) + c ...
+  SDValue Base = Ptr;
+  SDValue Index = SDValue();
+  int64_t Offset = 0;
+  bool IsIndexSignExt = false;
+
+  // Consume constant adds
+  while (Base->getOpcode() == ISD::ADD &&
+         isa<ConstantSDNode>(Base->getOperand(1))) {
+    int64_t POffset = cast<ConstantSDNode>(Base->getOperand(1))->getSExtValue();
+    Offset += POffset;
+    Base = Base->getOperand(0);
+  }
+
+  if (Base->getOpcode() == ISD::ADD) {
+    // TODO: The following code appears to be needless as it just
+    //       bails on some Ptrs early, reducing the cases where we
+    //       find equivalence. We should be able to remove this.
+    // Inside a loop the current BASE pointer is calculated using an ADD and a
+    // MUL instruction. In this case Base is the actual BASE pointer.
+    // (i64 add (i64 %array_ptr)
+    //          (i64 mul (i64 %induction_var)
+    //                   (i64 %element_size)))
+    if (Base->getOperand(1)->getOpcode() == ISD::MUL)
+      return BaseIndexOffset(Base, Index, Offset, IsIndexSignExt);
+
+    // Look at Base + Index + Offset cases.
+    Index = Base->getOperand(1);
+    SDValue PotentialBase = Base->getOperand(0);
+
+    // Skip signextends.
+    if (Index->getOpcode() == ISD::SIGN_EXTEND) {
+      Index = Index->getOperand(0);
+      IsIndexSignExt = true;
+    }
+
+    // Check if Index Offset pattern
+    if (Index->getOpcode() != ISD::ADD ||
+        !isa<ConstantSDNode>(Index->getOperand(1)))
+      return BaseIndexOffset(PotentialBase, Index, Offset, IsIndexSignExt);
+
+    Offset += cast<ConstantSDNode>(Index->getOperand(1))->getSExtValue();
+    Index = Index->getOperand(0);
+    if (Index->getOpcode() == ISD::SIGN_EXTEND) {
+      Index = Index->getOperand(0);
+      IsIndexSignExt = true;
+    } else
+      IsIndexSignExt = false;
+    Base = PotentialBase;
+  }
+  return BaseIndexOffset(Base, Index, Offset, IsIndexSignExt);
+}
+} // end namespace llvm