[Hexagon] Speed up frame lowering when no optimizations are enabled

- Do not optimize stack slots in optnone functions.
- Get aligned-base register from HexagonMachineFunctionInfo instead of
  looking for ALIGNA instruction in the function's body.

llvm-svn: 264580

llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp

@@ -287,6 +287,20 @@ namespace {
         return true;
     return false;
   }
+
+  inline bool isOptNone(const MachineFunction &MF) {
+    return MF.getFunction()->hasFnAttribute(Attribute::OptimizeNone) ||
+           MF.getTarget().getOptLevel() == CodeGenOpt::None;
+  }
+
+  inline bool isOptSize(const MachineFunction &MF) {
+    const Function &F = *MF.getFunction();
+    return F.optForSize() && !F.optForMinSize();
+  }
+
+  inline bool isMinSize(const MachineFunction &MF) {
+    return MF.getFunction()->optForMinSize();
+  }
 }
 
 
@@ -864,9 +878,8 @@ int HexagonFrameLowering::getFrameIndexReference(const MachineFunction &MF,
   bool NoOpt = MF.getTarget().getOptLevel() == CodeGenOpt::None;
 
   unsigned SP = HRI.getStackRegister(), FP = HRI.getFrameRegister();
-  unsigned AP = 0;
-  if (const MachineInstr *AI = getAlignaInstr(MF))
-    AP = AI->getOperand(0).getReg();
+  auto &HMFI = *MF.getInfo<HexagonMachineFunctionInfo>();
+  unsigned AP = HMFI.getStackAlignBasePhysReg();
   unsigned FrameSize = MFI.getStackSize();
 
   bool UseFP = false, UseAP = false;  // Default: use SP (except at -O0).
@@ -1089,6 +1102,13 @@ void HexagonFrameLowering::processFunctionBeforeFrameFinalized(
   if (A == 0)
     MFI->setLocalFrameMaxAlign(8);
   MFI->setUseLocalStackAllocationBlock(true);
+
+  // Set the physical aligned-stack base address register.
+  unsigned AP = 0;
+  if (const MachineInstr *AI = getAlignaInstr(MF))
+    AP = AI->getOperand(0).getReg();
+  auto &HMFI = *MF.getInfo<HexagonMachineFunctionInfo>();
+  HMFI.setStackAlignBasePhysReg(AP);
 }
 
 /// Returns true if there is no caller saved registers available.
@@ -1680,7 +1700,7 @@ void HexagonFrameLowering::determineCalleeSaves(MachineFunction &MF,
   // Replace predicate register pseudo spill code.
   SmallVector<unsigned,8> NewRegs;
   expandSpillMacros(MF, NewRegs);
-  if (OptimizeSpillSlots)
+  if (OptimizeSpillSlots && !isOptNone(MF))
     optimizeSpillSlots(MF, NewRegs);
 
   // We need to reserve a a spill slot if scavenging could potentially require
@@ -2145,18 +2165,6 @@ const MachineInstr *HexagonFrameLowering::getAlignaInstr(
 }
 
 
-// FIXME: Use Function::optForSize().
-inline static bool isOptSize(const MachineFunction &MF) {
-  AttributeSet AF = MF.getFunction()->getAttributes();
-  return AF.hasAttribute(AttributeSet::FunctionIndex,
-                         Attribute::OptimizeForSize);
-}
-
-inline static bool isMinSize(const MachineFunction &MF) {
-  return MF.getFunction()->optForMinSize();
-}
-
-
 /// Determine whether the callee-saved register saves and restores should
 /// be generated via inline code. If this function returns "true", inline
 /// code will be generated. If this function returns "false", additional

llvm/lib/Target/Hexagon/HexagonMachineFunctionInfo.h

@@ -27,7 +27,8 @@ class HexagonMachineFunctionInfo : public MachineFunctionInfo {
   // returning the value of the returned struct in a register. This field
   // holds the virtual register into which the sret argument is passed.
   unsigned SRetReturnReg;
-  unsigned StackAlignBaseReg;
+  unsigned StackAlignBaseVReg;    // Aligned-stack base register (virtual)
+  unsigned StackAlignBasePhysReg; //                             (physical)
   std::vector<MachineInstr*> AllocaAdjustInsts;
   int VarArgsFrameIndex;
   bool HasClobberLR;
@@ -36,13 +37,12 @@ class HexagonMachineFunctionInfo : public MachineFunctionInfo {
   virtual void anchor();
 
 public:
-  HexagonMachineFunctionInfo() : SRetReturnReg(0), StackAlignBaseReg(0),
-    HasClobberLR(0), HasEHReturn(false) {}
+  HexagonMachineFunctionInfo() : SRetReturnReg(0), StackAlignBaseVReg(0),
+      StackAlignBasePhysReg(0), HasClobberLR(0), HasEHReturn(false) {}
 
   HexagonMachineFunctionInfo(MachineFunction &MF) : SRetReturnReg(0),
-                                                    StackAlignBaseReg(0),
-                                                    HasClobberLR(0),
-                                                    HasEHReturn(false) {}
+      StackAlignBaseVReg(0), StackAlignBasePhysReg(0), HasClobberLR(0),
+      HasEHReturn(false) {}
 
   unsigned getSRetReturnReg() const { return SRetReturnReg; }
   void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }
@@ -77,8 +77,11 @@ public:
   bool hasEHReturn() const { return HasEHReturn; };
   void setHasEHReturn(bool H = true) { HasEHReturn = H; };
 
-  void setStackAlignBaseVReg(unsigned R) { StackAlignBaseReg = R; }
-  unsigned getStackAlignBaseVReg() const { return StackAlignBaseReg; }
+  void setStackAlignBaseVReg(unsigned R) { StackAlignBaseVReg = R; }
+  unsigned getStackAlignBaseVReg() const { return StackAlignBaseVReg; }
+
+  void setStackAlignBasePhysReg(unsigned R) { StackAlignBasePhysReg = R; }
+  unsigned getStackAlignBasePhysReg() const { return StackAlignBasePhysReg; }
 };
 } // End llvm namespace