[llvm-branch-commits] [llvm-branch] r91162 - in /llvm/branches/Apple/Zoidberg/lib/CodeGen: BranchFolding.cpp MachineBasicBlock.cpp

[Bill Wendling]

Author: void
Date: Fri Dec 11 15:49:37 2009
New Revision: 91162

URL: http://llvm.org/viewvc/llvm-project?rev=91162&view=rev
Log:
$ svn merge -c 91161 https://llvm.org/svn/llvm-project/llvm/trunk
--- Merging r91161 into '.':
U    lib/CodeGen/BranchFolding.cpp
U    lib/CodeGen/MachineBasicBlock.cpp


Modified:
    llvm/branches/Apple/Zoidberg/lib/CodeGen/BranchFolding.cpp
    llvm/branches/Apple/Zoidberg/lib/CodeGen/MachineBasicBlock.cpp

Modified: llvm/branches/Apple/Zoidberg/lib/CodeGen/BranchFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Zoidberg/lib/CodeGen/BranchFolding.cpp?rev=91162&r1=91161&r2=91162&view=diff

==============================================================================
--- llvm/branches/Apple/Zoidberg/lib/CodeGen/BranchFolding.cpp (original)
+++ llvm/branches/Apple/Zoidberg/lib/CodeGen/BranchFolding.cpp Fri Dec 11 15:49:37 2009
@@ -1205,11 +1205,11 @@
     }
   }
 
-  // If the prior block doesn't fall through into this block, and if this
-  // block doesn't fall through into some other block, see if we can find a
-  // place to move this block where a fall-through will happen.
-  if (!PrevBB.canFallThrough()) {
-
+  // If the prior block doesn't fall through into this block and if this block
+  // doesn't fall through into some other block and it's not branching only to a
+  // landing pad, then see if we can find a place to move this block where a
+  // fall-through will happen.
+  if (!PrevBB.canFallThrough() && !MBB->BranchesToLandingPad(MBB)) {
     // Now we know that there was no fall-through into this block, check to
     // see if it has a fall-through into its successor.
     bool CurFallsThru = MBB->canFallThrough();
@@ -1221,28 +1221,31 @@
            E = MBB->pred_end(); PI != E; ++PI) {
         // Analyze the branch at the end of the pred.
         MachineBasicBlock *PredBB = *PI;
-        MachineFunction::iterator PredFallthrough = PredBB; ++PredFallthrough;
+        MachineFunction::iterator PredNextBB = PredBB; ++PredNextBB;
         MachineBasicBlock *PredTBB, *PredFBB;
         SmallVector<MachineOperand, 4> PredCond;
-        if (PredBB != MBB && !PredBB->canFallThrough() &&
-            !TII->AnalyzeBranch(*PredBB, PredTBB, PredFBB, PredCond, true)
+        if (PredBB != MBB && !PredBB->canFallThrough()
+            && !TII->AnalyzeBranch(*PredBB, PredTBB, PredFBB, PredCond, true)
             && (!CurFallsThru || !CurTBB || !CurFBB)
             && (!CurFallsThru || MBB->getNumber() >= PredBB->getNumber())) {
-          // If the current block doesn't fall through, just move it.
-          // If the current block can fall through and does not end with a
-          // conditional branch, we need to append an unconditional jump to
-          // the (current) next block.  To avoid a possible compile-time
-          // infinite loop, move blocks only backward in this case.
-          // Also, if there are already 2 branches here, we cannot add a third;
-          // this means we have the case
-          // Bcc next
-          // B elsewhere
-          // next:
+          // If the current block doesn't fall through, just move it.  If the
+          // current block can fall through and does not end with a conditional
+          // branch, we need to append an unconditional jump to the (current)
+          // next block.  To avoid a possible compile-time infinite loop, move
+          // blocks only backward in this case.
+          // 
+          // Also, if there are already 2 branches here, we cannot add a third.
+          // I.e. we have the case:
+          // 
+          //     Bcc next
+          //     B elsewhere
+          //   next:
           if (CurFallsThru) {
-            MachineBasicBlock *NextBB = next(MachineFunction::iterator(MBB));
+            MachineBasicBlock *NextBB = MachineFunction::iterator(MBB);
             CurCond.clear();
             TII->InsertBranch(*MBB, NextBB, 0, CurCond);
           }
+
           MBB->moveAfter(PredBB);
           MadeChange = true;
           goto ReoptimizeBlock;

Modified: llvm/branches/Apple/Zoidberg/lib/CodeGen/MachineBasicBlock.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Zoidberg/lib/CodeGen/MachineBasicBlock.cpp?rev=91162&r1=91161&r2=91162&view=diff

==============================================================================
--- llvm/branches/Apple/Zoidberg/lib/CodeGen/MachineBasicBlock.cpp (original)
+++ llvm/branches/Apple/Zoidberg/lib/CodeGen/MachineBasicBlock.cpp Fri Dec 11 15:49:37 2009
@@ -457,16 +457,9 @@
   SmallSet<const MachineBasicBlock*, 32> Visited;
   const MachineBasicBlock *CurMBB = MBB;
 
-  while (!Visited.count(CurMBB) && !CurMBB->isLandingPad()) {
-    if (CurMBB->size() != 1 || CurMBB->succ_empty() || CurMBB->succ_size() != 1)
-      break;
-
-    const TargetInstrInfo *TII =
-      CurMBB->getParent()->getTarget().getInstrInfo();
-    if (!TII->isUnpredicatedTerminator(CurMBB->begin()))
-      break;
-
-    Visited.insert(CurMBB);
+  while (!CurMBB->isLandingPad()) {
+    if (CurMBB->succ_size() != 1) break;
+    if (!Visited.insert(CurMBB)) break;
     CurMBB = *CurMBB->succ_begin();
   }