Move TryToFoldFastISelLoad to FastISel, where it belongs. In general, I'm

trying to move as much FastISel logic as possible out of the main path in
SelectionDAGISel - intermixing them just adds confusion.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179902 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 19 insertions, 6 deletions

diff --git a/include/llvm/CodeGen/FastISel.h b/include/llvm/CodeGen/FastISel.h
index 705db7e643..be14f749bf 100644
--- a/include/llvm/CodeGen/FastISel.h
+++ b/include/llvm/CodeGen/FastISel.h
@@ -123,12 +123,28 @@ public:
   /// index value.
   std::pair<unsigned, bool> getRegForGEPIndex(const Value *V);
 
-  /// TryToFoldLoad - The specified machine instr operand is a vreg, and that
+  /// \brief We're checking to see if we can fold \p LI the \p FoldInst.
+  /// Note that we could have a sequence where multiple LLVM IR instructions
+  /// are folded into the same machineinstr.  For example we could have:
+  ///   A: x = load i32 *P
+  ///   B: y = icmp A, 42
+  ///   C: br y, ...
+  ///
+  /// In this scenario, \p LI is "A", and \p FoldInst is "C".  We know
+  /// about "B" (and any other folded instructions) because it is between
+  /// A and C.
+  ///
+  /// If we succeed folding, return true.
+  ///
+  bool tryToFoldLoad(const LoadInst *LI, const Instruction *FoldInst);
+
+  /// \brief The specified machine instr operand is a vreg, and that
   /// vreg is being provided by the specified load instruction.  If possible,
   /// try to fold the load as an operand to the instruction, returning true if
   /// possible.
-  virtual bool TryToFoldLoad(MachineInstr * /*MI*/, unsigned /*OpNo*/,
-                             const LoadInst * /*LI*/) {
+  /// This method should be implemented by targets.
+  virtual bool tryToFoldLoadIntoMI(MachineInstr * /*MI*/, unsigned /*OpNo*/,
+                                   const LoadInst * /*LI*/) {
     return false;
   }
 
diff --git a/include/llvm/CodeGen/SelectionDAGISel.h b/include/llvm/CodeGen/SelectionDAGISel.h
index 5f503deff1..a4721db685 100644
--- a/include/llvm/CodeGen/SelectionDAGISel.h
+++ b/include/llvm/CodeGen/SelectionDAGISel.h
@@ -259,9 +259,6 @@ private:
   void SelectBasicBlock(BasicBlock::const_iterator Begin,
                         BasicBlock::const_iterator End,
                         bool &HadTailCall);
-
-  bool TryToFoldFastISelLoad(const LoadInst *LI, const Instruction *FoldInst,
-                             FastISel *FastIS);
   void FinishBasicBlock();
 
   void CodeGenAndEmitDAG();