Test commit: fixed spelling error in comment.

[oota-llvm.git] / lib / CodeGen / SelectionDAG / FastISel.cpp

diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index a70b6fd6be4c412895542e95dac41d04c4a31343..cfbb20947acc7a41ecaa5ea3bc6dbae409d92f81 100644 (file)
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -1322,12 +1322,38 @@ bool FastISel::selectBitCast(const User *I) {
   return true;
 }
 
+// Remove local value instructions starting from the instruction after
+// SavedLastLocalValue to the current function insert point.
+void FastISel::removeDeadLocalValueCode(MachineInstr *SavedLastLocalValue)
+{
+  MachineInstr *CurLastLocalValue = getLastLocalValue();
+  if (CurLastLocalValue != SavedLastLocalValue) {
+    // Find the first local value instruction to be deleted. 
+    // This is the instruction after SavedLastLocalValue if it is non-NULL.
+    // Otherwise it's the first instruction in the block.
+    MachineBasicBlock::iterator FirstDeadInst(SavedLastLocalValue);
+    if (SavedLastLocalValue)
+      ++FirstDeadInst;
+    else
+      FirstDeadInst = FuncInfo.MBB->getFirstNonPHI();
+    setLastLocalValue(SavedLastLocalValue);
+    removeDeadCode(FirstDeadInst, FuncInfo.InsertPt);
+  }
+}
+
 bool FastISel::selectInstruction(const Instruction *I) {
+  MachineInstr *SavedLastLocalValue = getLastLocalValue();
   // Just before the terminator instruction, insert instructions to
   // feed PHI nodes in successor blocks.
   if (isa<TerminatorInst>(I))
-    if (!handlePHINodesInSuccessorBlocks(I->getParent()))
+    if (!handlePHINodesInSuccessorBlocks(I->getParent())) {
+      // PHI node handling may have generated local value instructions,
+      // even though it failed to handle all PHI nodes.
+      // We remove these instructions because SelectionDAGISel will generate 
+      // them again.
+      removeDeadLocalValueCode(SavedLastLocalValue);
       return false;
+    }
 
   DbgLoc = I->getDebugLoc();
 
@@ -1344,7 +1370,7 @@ bool FastISel::selectInstruction(const Instruction *I) {
         LibInfo->hasOptimizedCodeGen(Func))
       return false;
 
-    // Don't handle Intrinsic::trap if a trap funciton is specified.
+    // Don't handle Intrinsic::trap if a trap function is specified.
     if (F && F->getIntrinsicID() == Intrinsic::trap &&
         Call->hasFnAttr("trap-func-name"))
       return false;
@@ -1376,8 +1402,12 @@ bool FastISel::selectInstruction(const Instruction *I) {
 
   DbgLoc = DebugLoc();
   // Undo phi node updates, because they will be added again by SelectionDAG.
-  if (isa<TerminatorInst>(I))
+  if (isa<TerminatorInst>(I)) {
+    // PHI node handling may have generated local value instructions. 
+    // We remove them because SelectionDAGISel will generate them again.
+    removeDeadLocalValueCode(SavedLastLocalValue);
     FuncInfo.PHINodesToUpdate.resize(FuncInfo.OrigNumPHINodesToUpdate);
+  }
   return false;
 }