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, 8 insertions, 10 deletions

diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp
index af2544f17d..9df7697344 100644
--- a/lib/Target/X86/InstSelectSimple.cpp
+++ b/lib/Target/X86/InstSelectSimple.cpp
@@ -37,23 +37,21 @@ using namespace llvm;
 /// instruction at as well as a basic block.  This is the version for when you
 /// have a destination register in mind.
 inline static MachineInstrBuilder BMI(MachineBasicBlock *MBB,
-                                      MachineBasicBlock::iterator &I,
+                                      MachineBasicBlock::iterator I,
                                       int Opcode, unsigned NumOperands,
                                       unsigned DestReg) {
-  assert(I >= MBB->begin() && I <= MBB->end() && "Bad iterator!");
   MachineInstr *MI = new MachineInstr(Opcode, NumOperands+1, true, true);
-  I = MBB->insert(I, MI)+1;
+  MBB->insert(I, MI);
   return MachineInstrBuilder(MI).addReg(DestReg, MOTy::Def);
 }
 
 /// BMI - A special BuildMI variant that takes an iterator to insert the
 /// instruction at as well as a basic block.
 inline static MachineInstrBuilder BMI(MachineBasicBlock *MBB,
-                                      MachineBasicBlock::iterator &I,
+                                      MachineBasicBlock::iterator I,
                                       int Opcode, unsigned NumOperands) {
-  assert(I >= MBB->begin() && I <= MBB->end() && "Bad iterator!");
   MachineInstr *MI = new MachineInstr(Opcode, NumOperands, true, true);
-  I = MBB->insert(I, MI)+1;
+  MBB->insert(I, MI);
   return MachineInstrBuilder(MI);
 }
 
@@ -541,19 +539,19 @@ void ISel::SelectPHINodes() {
     MachineBasicBlock *MBB = MBBMap[I];
 
     // Loop over all of the PHI nodes in the LLVM basic block...
-    unsigned NumPHIs = 0;
+    MachineInstr* instr = MBB->begin();
     for (BasicBlock::const_iterator I = BB->begin();
          PHINode *PN = const_cast<PHINode*>(dyn_cast<PHINode>(I)); ++I) {
 
       // Create a new machine instr PHI node, and insert it.
       unsigned PHIReg = getReg(*PN);
       MachineInstr *PhiMI = BuildMI(X86::PHI, PN->getNumOperands(), PHIReg);
-      MBB->insert(MBB->begin()+NumPHIs++, PhiMI);
+      MBB->insert(instr, PhiMI);
 
       MachineInstr *LongPhiMI = 0;
       if (PN->getType() == Type::LongTy || PN->getType() == Type::ULongTy) {
         LongPhiMI = BuildMI(X86::PHI, PN->getNumOperands(), PHIReg+1);
-        MBB->insert(MBB->begin()+NumPHIs++, LongPhiMI);
+        MBB->insert(instr, LongPhiMI);
       }
 
       // PHIValues - Map of blocks to incoming virtual registers.  We use this
@@ -588,7 +586,7 @@ void ISel::SelectPHINodes() {
             MachineBasicBlock::iterator PI = PredMBB->begin();
 
             // Skip over any PHI nodes though!
-            while (PI != PredMBB->end() && (*PI)->getOpcode() == X86::PHI)
+            while (PI != PredMBB->end() && PI->getOpcode() == X86::PHI)
               ++PI;
 
             ValReg = getReg(Val, PredMBB, PI);