Add hasLoadFromStackSlot and hasStoreToStackSlot to return whether a

machine instruction loads or stores from/to a stack slot.  Unlike
isLoadFromStackSlot and isStoreFromStackSlot, the instruction may be
something other than a pure load/store (e.g. it may be an arithmetic
operation with a memory operand).  This helps AsmPrinter determine when
to print a spill/reload comment.

This is only a hint since we may not be able to figure this out in all
cases.  As such, it should not be relied upon for correctness.

Implement for X86.  Return false by default for other architectures.

llvm-svn: 87026

llvm/include/llvm/Target/TargetInstrInfo.h

@@ -170,6 +170,17 @@ public:
                                        int &FrameIndex) const {
     return 0;
   }
+
+  /// hasLoadFromStackSlot - If the specified machine instruction has
+  /// a load from a stack slot, return true along with the FrameIndex
+  /// of the loaded stack slot.  If not, return false.  Unlike
+  /// isLoadFromStackSlot, this returns true for any instructions that
+  /// loads from the stack.  This is just a hint, as some cases may be
+  /// missed.
+  virtual bool hasLoadFromStackSlot(const MachineInstr *MI,
+                                    int &FrameIndex) const {
+    return 0;
+  }
   
   /// isStoreToStackSlot - If the specified machine instruction is a direct
   /// store to a stack slot, return the virtual or physical register number of
@@ -181,6 +192,17 @@ public:
     return 0;
   }
 
+  /// hasStoreToStackSlot - If the specified machine instruction has a
+  /// store to a stack slot, return true along with the FrameIndex of
+  /// the loaded stack slot.  If not, return false.  Unlike
+  /// isStoreToStackSlot, this returns true for any instructions that
+  /// loads from the stack.  This is just a hint, as some cases may be
+  /// missed.
+  virtual bool hasStoreToStackSlot(const MachineInstr *MI,
+                                   int &FrameIndex) const {
+    return 0;
+  }
+
   /// reMaterialize - Re-issue the specified 'original' instruction at the
   /// specific location targeting a new destination register.
   virtual void reMaterialize(MachineBasicBlock &MBB,

llvm/lib/Target/X86/X86InstrInfo.cpp

@@ -26,11 +26,15 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/LiveVariables.h"
+#include "llvm/CodeGen/PseudoSourceValue.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/MC/MCAsmInfo.h"
+
+#include <limits>
+
 using namespace llvm;
 
 static cl::opt<bool>
@@ -707,6 +711,21 @@ bool X86InstrInfo::isMoveInstr(const MachineInstr& MI,
   }
 }
 
+/// isFrameOperand - Return true and the FrameIndex if the specified
+/// operand and follow operands form a reference to the stack frame.
+bool X86InstrInfo::isFrameOperand(const MachineInstr *MI, unsigned int Op,
+                                  int &FrameIndex) const {
+  if (MI->getOperand(Op).isFI() && MI->getOperand(Op+1).isImm() &&
+      MI->getOperand(Op+2).isReg() && MI->getOperand(Op+3).isImm() &&
+      MI->getOperand(Op+1).getImm() == 1 &&
+      MI->getOperand(Op+2).getReg() == 0 &&
+      MI->getOperand(Op+3).getImm() == 0) {
+    FrameIndex = MI->getOperand(Op).getIndex();
+    return true;
+  }
+  return false;
+}
+
 unsigned X86InstrInfo::isLoadFromStackSlot(const MachineInstr *MI, 
                                            int &FrameIndex) const {
   switch (MI->getOpcode()) {
@@ -723,19 +742,32 @@ unsigned X86InstrInfo::isLoadFromStackSlot(const MachineInstr *MI,
   case X86::MOVDQArm:
   case X86::MMX_MOVD64rm:
   case X86::MMX_MOVQ64rm:
-    if (MI->getOperand(1).isFI() && MI->getOperand(2).isImm() &&
-        MI->getOperand(3).isReg() && MI->getOperand(4).isImm() &&
-        MI->getOperand(2).getImm() == 1 &&
-        MI->getOperand(3).getReg() == 0 &&
-        MI->getOperand(4).getImm() == 0) {
-      FrameIndex = MI->getOperand(1).getIndex();
+    if (isFrameOperand(MI, 1, FrameIndex)) {
       return MI->getOperand(0).getReg();
     }
+    // Check for post-frame index elimination operations
+    return hasLoadFromStackSlot(MI, FrameIndex);
     break;
   }
   return 0;
 }
 
+bool X86InstrInfo::hasLoadFromStackSlot(const MachineInstr *MI,
+                                        int &FrameIndex) const {
+  for (MachineInstr::mmo_iterator o = MI->memoperands_begin(),
+         oe = MI->memoperands_end();
+       o != oe;
+       ++o) {
+    if ((*o)->isLoad() && (*o)->getValue())
+      if (const FixedStackPseudoSourceValue *Value =
+          dyn_cast<const FixedStackPseudoSourceValue>((*o)->getValue())) {
+        FrameIndex = Value->getFrameIndex();
+        return true;
+      }
+  }
+  return false;
+}
+
 unsigned X86InstrInfo::isStoreToStackSlot(const MachineInstr *MI,
                                           int &FrameIndex) const {
   switch (MI->getOpcode()) {
@@ -753,19 +785,32 @@ unsigned X86InstrInfo::isStoreToStackSlot(const MachineInstr *MI,
   case X86::MMX_MOVD64mr:
   case X86::MMX_MOVQ64mr:
   case X86::MMX_MOVNTQmr:
-    if (MI->getOperand(0).isFI() && MI->getOperand(1).isImm() &&
-        MI->getOperand(2).isReg() && MI->getOperand(3).isImm() &&
-        MI->getOperand(1).getImm() == 1 &&
-        MI->getOperand(2).getReg() == 0 &&
-        MI->getOperand(3).getImm() == 0) {
-      FrameIndex = MI->getOperand(0).getIndex();
+    if (isFrameOperand(MI, 0, FrameIndex)) {
       return MI->getOperand(X86AddrNumOperands).getReg();
     }
+    // Check for post-frame index elimination operations
+    return hasStoreToStackSlot(MI, FrameIndex);
     break;
   }
   return 0;
 }
 
+bool X86InstrInfo::hasStoreToStackSlot(const MachineInstr *MI,
+                                       int &FrameIndex) const {
+  for (MachineInstr::mmo_iterator o = MI->memoperands_begin(),
+         oe = MI->memoperands_end();
+       o != oe;
+       ++o) {
+    if ((*o)->isStore() && (*o)->getValue())
+      if (const FixedStackPseudoSourceValue *Value =
+          dyn_cast<const FixedStackPseudoSourceValue>((*o)->getValue())) {
+        FrameIndex = Value->getFrameIndex();
+        return true;
+      }
+  }
+  return false;
+}
+
 /// regIsPICBase - Return true if register is PIC base (i.e.g defined by
 /// X86::MOVPC32r.
 static bool regIsPICBase(unsigned BaseReg, const MachineRegisterInfo &MRI) {

llvm/lib/Target/X86/X86InstrInfo.h

@@ -449,8 +449,25 @@ public:
                            unsigned &SrcSubIdx, unsigned &DstSubIdx) const;
 
   unsigned isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const;
+
+  /// hasLoadFromStackSlot - If the specified machine instruction has
+  /// a load from a stack slot, return true along with the FrameIndex
+  /// of the loaded stack slot.  If not, return false.  Unlike
+  /// isLoadFromStackSlot, this returns true for any instructions that
+  /// loads from the stack.  This is a hint only and may not catch all
+  /// cases.
+  bool hasLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const;
+
   unsigned isStoreToStackSlot(const MachineInstr *MI, int &FrameIndex) const;
 
+  /// hasStoreToStackSlot - If the specified machine instruction has a
+  /// store to a stack slot, return true along with the FrameIndex of
+  /// the loaded stack slot.  If not, return false.  Unlike
+  /// isStoreToStackSlot, this returns true for any instructions that
+  /// loads from the stack.  This is a hint only and may not catch all
+  /// cases.
+  bool hasStoreToStackSlot(const MachineInstr *MI, int &FrameIndex) const;
+
   bool isReallyTriviallyReMaterializable(const MachineInstr *MI,
                                          AliasAnalysis *AA) const;
   void reMaterialize(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
@@ -610,6 +627,11 @@ private:
                                      unsigned OpNum,
                                      const SmallVectorImpl<MachineOperand> &MOs,
                                      unsigned Size, unsigned Alignment) const;
+
+  /// isFrameOperand - Return true and the FrameIndex if the specified
+  /// operand and follow operands form a reference to the stack frame.
+  bool isFrameOperand(const MachineInstr *MI, unsigned int Op,
+                      int &FrameIndex) const;
 };
 
 } // End llvm namespace