[r257857] lli: use llvm::utostr() instead of std::to_string().

[oota-llvm.git] / lib / CodeGen / MachineCopyPropagation.cpp

diff --git a/lib/CodeGen/MachineCopyPropagation.cpp b/lib/CodeGen/MachineCopyPropagation.cpp
index 1673498f1789e6c4c9b0204a84cee718830d03ae..a6863412132bdb800b907c43406764f205051f80 100644 (file)
--- a/lib/CodeGen/MachineCopyPropagation.cpp
+++ b/lib/CodeGen/MachineCopyPropagation.cpp
@@ -11,27 +11,31 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "codegen-cp"
 #include "llvm/CodeGen/Passes.h"
-#include "llvm/Pass.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Pass.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
 using namespace llvm;
 
+#define DEBUG_TYPE "codegen-cp"
+
 STATISTIC(NumDeletes, "Number of dead copies deleted");
 
 namespace {
   class MachineCopyPropagation : public MachineFunctionPass {
     const TargetRegisterInfo *TRI;
+    const TargetInstrInfo *TII;
     MachineRegisterInfo *MRI;
 
   public:
@@ -40,7 +44,7 @@ namespace {
      initializeMachineCopyPropagationPass(*PassRegistry::getPassRegistry());
     }
 
-    virtual bool runOnMachineFunction(MachineFunction &MF);
+    bool runOnMachineFunction(MachineFunction &MF) override;
 
   private:
     typedef SmallVector<unsigned, 4> DestList;
@@ -70,10 +74,9 @@ MachineCopyPropagation::SourceNoLongerAvailable(unsigned Reg,
            I != E; ++I) {
         unsigned MappedDef = *I;
         // Source of copy is no longer available for propagation.
-        if (AvailCopyMap.erase(MappedDef)) {
-          for (MCSubRegIterator SR(MappedDef, TRI); SR.isValid(); ++SR)
-            AvailCopyMap.erase(*SR);
-        }
+        AvailCopyMap.erase(MappedDef);
+        for (MCSubRegIterator SR(MappedDef, TRI); SR.isValid(); ++SR)
+          AvailCopyMap.erase(*SR);
       }
     }
   }
@@ -129,6 +132,8 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
   DenseMap<unsigned, MachineInstr*> CopyMap;         // Def -> copies map
   SourceMap SrcMap; // Src -> Def map
 
+  DEBUG(dbgs() << "MCP: CopyPropagateBlock " << MBB.getName() << "\n");
+
   bool Changed = false;
   for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ) {
     MachineInstr *MI = &*I;
@@ -163,6 +168,8 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
           // CALL
           // %RAX<def> = COPY %RSP
 
+          DEBUG(dbgs() << "MCP: copy is a NOP, removing: "; MI->dump());
+
           // Clear any kills of Def between CopyMI and MI. This extends the
           // live range.
           for (MachineBasicBlock::iterator I = CopyMI, E = MI; I != E; ++I)
@@ -178,10 +185,14 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
       // If Src is defined by a previous copy, it cannot be eliminated.
       for (MCRegAliasIterator AI(Src, TRI, true); AI.isValid(); ++AI) {
         CI = CopyMap.find(*AI);
-        if (CI != CopyMap.end())
+        if (CI != CopyMap.end()) {
+          DEBUG(dbgs() << "MCP: Copy is no longer dead: "; CI->second->dump());
           MaybeDeadCopies.remove(CI->second);
+        }
       }
 
+      DEBUG(dbgs() << "MCP: Copy is a deletion candidate: "; MI->dump());
+
       // Copy is now a candidate for deletion.
       MaybeDeadCopies.insert(MI);
 
@@ -200,9 +211,8 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
         CopyMap.erase(*AI);
         AvailCopyMap.erase(*AI);
       }
-      CopyMap[Def] = MI;
-      AvailCopyMap[Def] = MI;
-      for (MCSubRegIterator SR(Def, TRI); SR.isValid(); ++SR) {
+      for (MCSubRegIterator SR(Def, TRI, /*IncludeSelf=*/true); SR.isValid();
+           ++SR) {
         CopyMap[*SR] = MI;
         AvailCopyMap[*SR] = MI;
       }
@@ -243,9 +253,19 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
       // for elimination.
       for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) {
         DenseMap<unsigned, MachineInstr*>::iterator CI = CopyMap.find(*AI);
-        if (CI != CopyMap.end())
+        if (CI != CopyMap.end()) {
+          DEBUG(dbgs() << "MCP: Copy is used - not dead: "; CI->second->dump());
           MaybeDeadCopies.remove(CI->second);
+        }
       }
+      // Treat undef use like defs for copy propagation but not for
+      // dead copy. We would need to do a liveness check to be sure the copy
+      // is dead for undef uses.
+      // The backends are allowed to do whatever they want with undef value
+      // and we cannot be sure this register will not be rewritten to break
+      // some false dependencies for the hardware for instance.
+      if (MO.isUndef())
+        Defs.push_back(Reg);
     }
 
     // The instruction has a register mask operand which means that it clobbers
@@ -261,6 +281,8 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
         unsigned Reg = (*DI)->getOperand(0).getReg();
         if (MRI->isReserved(Reg) || !MaskMO.clobbersPhysReg(Reg))
           continue;
+        DEBUG(dbgs() << "MCP: Removing copy due to regmask clobbering: ";
+              (*DI)->dump());
         (*DI)->eraseFromParent();
         Changed = true;
         ++NumDeletes;
@@ -308,9 +330,13 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
 }
 
 bool MachineCopyPropagation::runOnMachineFunction(MachineFunction &MF) {
+  if (skipOptnoneFunction(*MF.getFunction()))
+    return false;
+
   bool Changed = false;
 
-  TRI = MF.getTarget().getRegisterInfo();
+  TRI = MF.getSubtarget().getRegisterInfo();
+  TII = MF.getSubtarget().getInstrInfo();
   MRI = &MF.getRegInfo();
 
   for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)