Reverts wrong modification to MachineBlockPlacement & BranchFolding; uses a new strat...

[oota-llvm.git] / include / llvm / CodeGen / MachineInstr.h

diff --git a/include/llvm/CodeGen/MachineInstr.h b/include/llvm/CodeGen/MachineInstr.h
index 978864e96ca53b99ebb0eb87b11e43fce0f6170d..3e76ea9c31dd7f5e082962855a7338b1d9441686 100644 (file)
--- a/include/llvm/CodeGen/MachineInstr.h
+++ b/include/llvm/CodeGen/MachineInstr.h
@@ -71,6 +71,9 @@ public:
     BundledSucc  = 1 << 3               // Instruction has bundled successors.
   };
 private:
+  // XXX-update: A flag that checks whether we can eliminate this instruction.
+  bool canEliminateMachineInstr;
+
   const MCInstrDesc *MCID;              // Instruction descriptor.
   MachineBasicBlock *Parent;            // Pointer to the owning basic block.
 
@@ -97,7 +100,7 @@ private:
   // of memory operands required to be precise exceeds the maximum value of
   // NumMemRefs - currently 256 - we remove the operands entirely. Note also
   // that this is a non-owning reference to a shared copy on write buffer owned
-  // by the MachineFunction and created via MF.allocateMemRefsArray. 
+  // by the MachineFunction and created via MF.allocateMemRefsArray.
   mmo_iterator MemRefs;
 
   DebugLoc debugLoc;                    // Source line information.
@@ -126,6 +129,15 @@ private:
   friend class MachineFunction;
 
 public:
+  // XXX-update:
+  void disableCanEliminateMachineInstr() {
+    canEliminateMachineInstr = false;
+  }
+
+  bool getCanEliminateMachineInstr() {
+    return canEliminateMachineInstr;
+  }
+
   const MachineBasicBlock* getParent() const { return Parent; }
   MachineBasicBlock* getParent() { return Parent; }
 
@@ -354,7 +366,7 @@ public:
   mmo_iterator memoperands_end() const { return MemRefs + NumMemRefs; }
   /// Return true if we don't have any memory operands which described the the
   /// memory access done by this instruction.  If this is true, calling code
-  /// must be conservative.    
+  /// must be conservative.
   bool memoperands_empty() const { return NumMemRefs == 0; }
 
   iterator_range<mmo_iterator>  memoperands() {
@@ -774,7 +786,7 @@ public:
   bool isKill() const { return getOpcode() == TargetOpcode::KILL; }
   bool isImplicitDef() const { return getOpcode()==TargetOpcode::IMPLICIT_DEF; }
   bool isInlineAsm() const { return getOpcode() == TargetOpcode::INLINEASM; }
-  bool isMSInlineAsm() const { 
+  bool isMSInlineAsm() const {
     return getOpcode() == TargetOpcode::INLINEASM && getInlineAsmDialect();
   }
   bool isStackAligningInlineAsm() const;
@@ -1180,11 +1192,26 @@ public:
   /// Assign this MachineInstr's memory reference descriptor list.
   /// This does not transfer ownership.
   void setMemRefs(mmo_iterator NewMemRefs, mmo_iterator NewMemRefsEnd) {
-    MemRefs = NewMemRefs;
-    NumMemRefs = uint8_t(NewMemRefsEnd - NewMemRefs);
-    assert(NumMemRefs == NewMemRefsEnd - NewMemRefs && "Too many memrefs");
+    setMemRefs(std::make_pair(NewMemRefs, NewMemRefsEnd-NewMemRefs));
+  }
+
+  /// Assign this MachineInstr's memory reference descriptor list.  First
+  /// element in the pair is the begin iterator/pointer to the array; the
+  /// second is the number of MemoryOperands.  This does not transfer ownership
+  /// of the underlying memory.
+  void setMemRefs(std::pair<mmo_iterator, unsigned> NewMemRefs) {
+    MemRefs = NewMemRefs.first;
+    NumMemRefs = uint8_t(NewMemRefs.second);
+    assert(NumMemRefs == NewMemRefs.second &&
+           "Too many memrefs - must drop memory operands");
   }
 
+  /// Return a set of memrefs (begin iterator, size) which conservatively
+  /// describe the memory behavior of both MachineInstrs.  This is appropriate
+  /// for use when merging two MachineInstrs into one. This routine does not
+  /// modify the memrefs of the this MachineInstr.
+  std::pair<mmo_iterator, unsigned> mergeMemRefsWith(const MachineInstr& Other);
+
   /// Clear this MachineInstr's memory reference descriptor list.  This resets
   /// the memrefs to their most conservative state.  This should be used only
   /// as a last resort since it greatly pessimizes our knowledge of the memory