Enable rematerialization of constants using AliasAnalysis::pointsToConstantMemory,

and knowledge of PseudoSourceValues. This unfortunately isn't sufficient to allow
constants to be rematerialized in PIC mode -- the extra indirection is a
complication.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54000 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 16 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index ebbcf63b70..c88c1ec696 100644
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -32,6 +32,7 @@
 
 namespace llvm {
 
+  class AliasAnalysis;
   class LiveVariables;
   class MachineLoopInfo;
   class TargetRegisterInfo;
@@ -61,6 +62,7 @@ namespace llvm {
     const TargetMachine* tm_;
     const TargetRegisterInfo* tri_;
     const TargetInstrInfo* tii_;
+    AliasAnalysis *aa_;
     LiveVariables* lv_;
 
     /// Special pool allocator for VNInfo's (LiveInterval val#).
diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h
index bfa6d1ccd0..b851fdf66d 100644
--- a/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -206,6 +206,14 @@ public:
   liveout_iterator liveout_begin() const { return LiveOuts.begin(); }
   liveout_iterator liveout_end()   const { return LiveOuts.end(); }
   bool             liveout_empty() const { return LiveOuts.empty(); }
+
+  bool isLiveIn(unsigned Reg) const {
+    for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I)
+      if (I->first == Reg || I->second == Reg)
+        return true;
+    return false;
+  }
+
 private:
   void HandleVRegListReallocation();
   
diff --git a/include/llvm/CodeGen/PseudoSourceValue.h b/include/llvm/CodeGen/PseudoSourceValue.h
index 95ae1d43ab..115e565b6b 100644
--- a/include/llvm/CodeGen/PseudoSourceValue.h
+++ b/include/llvm/CodeGen/PseudoSourceValue.h
@@ -17,6 +17,8 @@
 #include "llvm/Value.h"
 
 namespace llvm {
+  class MachineFrameInfo;
+
   /// PseudoSourceValue - Special value supplied for machine level alias
   /// analysis. It indicates that the a memory access references the functions
   /// stack frame (e.g., a spill slot), below the stack frame (e.g., argument
@@ -27,6 +29,10 @@ namespace llvm {
 
     virtual void print(std::ostream &OS) const;
 
+    /// isConstant - Test whether this PseudoSourceValue has a constant value.
+    ///
+    virtual bool isConstant(const MachineFrameInfo *) const;
+
     /// classof - Methods for support type inquiry through isa, cast, and
     /// dyn_cast:
     ///