Change MachineBasicBlock's vector of MachineInstr pointers into an

ilist of MachineInstr objects. This allows constant time removal and
insertion of MachineInstr instances from anywhere in each
MachineBasicBlock. It also allows for constant time splicing of
MachineInstrs into or out of MachineBasicBlocks.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11340 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 29 insertions, 21 deletions

diff --git a/lib/Target/X86/FloatingPoint.cpp b/lib/Target/X86/FloatingPoint.cpp
index 0a0fe9b2c2..53f6ec0feb 100644
--- a/lib/Target/X86/FloatingPoint.cpp
+++ b/lib/Target/X86/FloatingPoint.cpp
@@ -118,7 +118,7 @@ namespace {
 
 	// Emit an fxch to update the runtime processors version of the state
 	MachineInstr *MI = BuildMI(X86::FXCH, 1).addReg(STReg);
-	I = 1+MBB->insert(I, MI);
+	MBB->insert(I, MI);
 	NumFXCH++;
       }
     }
@@ -129,7 +129,7 @@ namespace {
       pushReg(AsReg);   // New register on top of stack
 
       MachineInstr *MI = BuildMI(X86::FLDrr, 1).addReg(STReg);
-      I = 1+MBB->insert(I, MI);
+      MBB->insert(I, MI);
     }
 
     // popStackAfter - Pop the current value off of the top of the FP stack
@@ -193,12 +193,17 @@ bool FPS::processBasicBlock(MachineFunction &MF, MachineBasicBlock &BB) {
   MBB = &BB;
   
   for (MachineBasicBlock::iterator I = BB.begin(); I != BB.end(); ++I) {
-    MachineInstr *MI = *I;
+    MachineInstr *MI = I;
     unsigned Flags = TII.get(MI->getOpcode()).TSFlags;
     if ((Flags & X86II::FPTypeMask) == X86II::NotFP)
       continue;  // Efficiently ignore non-fp insts!
 
-    MachineInstr *PrevMI = I == BB.begin() ? 0 : *(I-1);
+    MachineInstr *PrevMI = 0;
+    if (I != BB.begin()) {
+        MachineBasicBlock::iterator tmp = I;
+        --tmp;
+        PrevMI = tmp;
+    }
 
     ++NumFP;  // Keep track of # of pseudo instrs
     DEBUG(std::cerr << "\nFPInst:\t";
@@ -242,15 +247,17 @@ bool FPS::processBasicBlock(MachineFunction &MF, MachineBasicBlock &BB) {
     }
     
     // Print out all of the instructions expanded to if -debug
-    DEBUG(if (*I == PrevMI) {
+    DEBUG(if (&*I == PrevMI) {
             std::cerr<< "Just deleted pseudo instruction\n";
           } else {
 	    MachineBasicBlock::iterator Start = I;
 	    // Rewind to first instruction newly inserted.
-	    while (Start != BB.begin() && *(Start-1) != PrevMI) --Start;
+	    while (Start != BB.begin() &&
+                   --Start != MachineBasicBlock::iterator(PrevMI));
+            ++Start;
 	    std::cerr << "Inserted instructions:\n\t";
-	    (*Start)->print(std::cerr, MF.getTarget());
-	    while (++Start != I+1);
+	    Start->print(std::cerr, MF.getTarget());
+	    while (++Start != I); ++Start;
 	  }
 	  dumpStack();
 	  );
@@ -344,15 +351,15 @@ void FPS::popStackAfter(MachineBasicBlock::iterator &I) {
   RegMap[Stack[--StackTop]] = ~0;     // Update state
 
   // Check to see if there is a popping version of this instruction...
-  int Opcode = Lookup(PopTable, ARRAY_SIZE(PopTable), (*I)->getOpcode());
+  int Opcode = Lookup(PopTable, ARRAY_SIZE(PopTable), I->getOpcode());
   if (Opcode != -1) {
-    (*I)->setOpcode(Opcode);
+    I->setOpcode(Opcode);
     if (Opcode == X86::FUCOMPPr)
-      (*I)->RemoveOperand(0);
+      I->RemoveOperand(0);
 
   } else {    // Insert an explicit pop
     MachineInstr *MI = BuildMI(X86::FSTPrr, 1).addReg(X86::ST0);
-    I = MBB->insert(I+1, MI);
+    I = MBB->insert(++I, MI);
   }
 }
 
@@ -371,7 +378,7 @@ static unsigned getFPReg(const MachineOperand &MO) {
 /// handleZeroArgFP - ST(0) = fld0    ST(0) = flds <mem>
 ///
 void FPS::handleZeroArgFP(MachineBasicBlock::iterator &I) {
-  MachineInstr *MI = *I;
+  MachineInstr *MI = I;
   unsigned DestReg = getFPReg(MI->getOperand(0));
   MI->RemoveOperand(0);   // Remove the explicit ST(0) operand
 
@@ -382,7 +389,7 @@ void FPS::handleZeroArgFP(MachineBasicBlock::iterator &I) {
 /// handleOneArgFP - fst <mem>, ST(0)
 ///
 void FPS::handleOneArgFP(MachineBasicBlock::iterator &I) {
-  MachineInstr *MI = *I;
+  MachineInstr *MI = I;
   assert((MI->getNumOperands() == 5 || MI->getNumOperands() == 1) &&
          "Can only handle fst* & ftst instructions!");
 
@@ -418,7 +425,7 @@ void FPS::handleOneArgFP(MachineBasicBlock::iterator &I) {
 /// handleOneArgFPRW - fchs - ST(0) = -ST(0)
 ///
 void FPS::handleOneArgFPRW(MachineBasicBlock::iterator &I) {
-  MachineInstr *MI = *I;
+  MachineInstr *MI = I;
   assert(MI->getNumOperands() == 2 && "Can only handle fst* instructions!");
 
   // Is this the last use of the source register?
@@ -503,7 +510,7 @@ static const TableEntry ReverseSTiTable[] = {
 void FPS::handleTwoArgFP(MachineBasicBlock::iterator &I) {
   ASSERT_SORTED(ForwardST0Table); ASSERT_SORTED(ReverseST0Table);
   ASSERT_SORTED(ForwardSTiTable); ASSERT_SORTED(ReverseSTiTable);
-  MachineInstr *MI = *I;
+  MachineInstr *MI = I;
 
   unsigned NumOperands = MI->getNumOperands();
   assert(NumOperands == 3 ||
@@ -588,7 +595,8 @@ void FPS::handleTwoArgFP(MachineBasicBlock::iterator &I) {
   unsigned NotTOS = (TOS == Op0) ? Op1 : Op0;
 
   // Replace the old instruction with a new instruction
-  *I = BuildMI(Opcode, 1).addReg(getSTReg(NotTOS));
+  MBB->remove(I);
+  I = MBB->insert(I, BuildMI(Opcode, 1).addReg(getSTReg(NotTOS)));
 
   // If both operands are killed, pop one off of the stack in addition to
   // overwriting the other one.
@@ -617,7 +625,7 @@ void FPS::handleTwoArgFP(MachineBasicBlock::iterator &I) {
 	Stack[--StackTop] = ~0;
 	
 	MachineInstr *MI = BuildMI(X86::FSTPrr, 1).addReg(STReg);
-	I = MBB->insert(I+1, MI);
+	I = MBB->insert(++I, MI);
       }
     }
   }
@@ -639,7 +647,7 @@ void FPS::handleTwoArgFP(MachineBasicBlock::iterator &I) {
 /// instructions.
 ///
 void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) {
-  MachineInstr *MI = *I;
+  MachineInstr *MI = I;
   switch (MI->getOpcode()) {
   default: assert(0 && "Unknown SpecialFP instruction!");
   case X86::FpGETRESULT:  // Appears immediately after a call returning FP type!
@@ -675,6 +683,6 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) {
   }
   }
 
-  I = MBB->erase(I)-1;  // Remove the pseudo instruction
-  delete MI;
+  I = MBB->erase(I);  // Remove the pseudo instruction
+  --I;
 }