[llvm-commits] CVS: llvm/lib/Transforms/Scalar/LoopUnswitch.cpp

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Scalar:

LoopUnswitch.cpp updated: 1.15 -> 1.16
---
Log message:

Update PHI nodes in successors of exit blocks.


---
Diffs of the changes:  (+34 -5)

 LoopUnswitch.cpp |   39 ++++++++++++++++++++++++++++++++++-----
 1 files changed, 34 insertions(+), 5 deletions(-)


Index: llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
diff -u llvm/lib/Transforms/Scalar/LoopUnswitch.cpp:1.15 llvm/lib/Transforms/Scalar/LoopUnswitch.cpp:1.16
--- llvm/lib/Transforms/Scalar/LoopUnswitch.cpp:1.15	Fri Feb 10 17:16:39 2006
+++ llvm/lib/Transforms/Scalar/LoopUnswitch.cpp	Fri Feb 10 17:26:14 2006
@@ -256,6 +256,16 @@
   // loop.
   for (Loop::block_iterator I = L->block_begin(), E = L->block_end();
        I != E; ++I) {
+    for (BasicBlock::iterator BBI = (*I)->begin(), E = (*I)->end(); 
+         BBI != E; ++BBI)
+      if (SelectInst *SI = dyn_cast<SelectInst>(BBI)) {
+        Value *LoopCond = FindLIVLoopCondition(SI->getCondition(), L, Changed);
+        if (LoopCond == 0) continue;
+        
+        //if (UnswitchIfProfitable(LoopCond, 
+        std::cerr << "LOOP INVARIANT SELECT: " << *SI;
+      }
+        
     TerminatorInst *TI = (*I)->getTerminator();
     // FIXME: Handle invariant select instructions.
     
@@ -523,13 +533,32 @@
 
   // Now we create the new Loop object for the versioned loop.
   Loop *NewLoop = CloneLoop(L, L->getParentLoop(), ValueMap, LI);
-  if (Loop *Parent = L->getParentLoop()) {
+  Loop *ParentLoop = L->getParentLoop();
+  if (ParentLoop) {
     // Make sure to add the cloned preheader and exit blocks to the parent loop
     // as well.
-    Parent->addBasicBlockToLoop(NewBlocks[0], *LI);
-    for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i)
-      Parent->addBasicBlockToLoop(cast<BasicBlock>(ValueMap[ExitBlocks[i]]),
-                                  *LI);
+    ParentLoop->addBasicBlockToLoop(NewBlocks[0], *LI);
+  }
+  
+  for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) {
+    BasicBlock *NewExit = cast<BasicBlock>(ValueMap[ExitBlocks[i]]);
+    if (ParentLoop)
+      ParentLoop->addBasicBlockToLoop(cast<BasicBlock>(NewExit), *LI);
+    
+    assert(NewExit->getTerminator()->getNumSuccessors() == 1 &&
+           "Exit block should have been split to have one successor!");
+    BasicBlock *ExitSucc = NewExit->getTerminator()->getSuccessor(0);
+    
+    // If the successor of the exit block had PHI nodes, add an entry for
+    // NewExit.
+    PHINode *PN;
+    for (BasicBlock::iterator I = ExitSucc->begin();
+         (PN = dyn_cast<PHINode>(I)); ++I) {
+      Value *V = PN->getIncomingValueForBlock(ExitBlocks[i]);
+      std::map<const Value *, Value*>::iterator It = ValueMap.find(V);
+      if (It != ValueMap.end()) V = It->second;
+      PN->addIncoming(V, NewExit);
+    }
   }
 
   // Rewrite the code to refer to itself.