From: Dale Johannesen <dalej@apple.com>
Date: Tue, 15 May 2007 21:19:17 +0000 (+0000)
Subject: Remove extra CFG edges before doing these passes; it makes them happier.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=14ba0cc42959a3fcc9b6781aea614b01877fb55f;p=oota-llvm.git

Remove extra CFG edges before doing these passes; it makes them happier.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37089 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index 5fe0486eb10..7b4aaae4824 100644
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -73,6 +73,12 @@ namespace {
   char BranchFolder::ID = 0;
 }
 
+static bool CorrectExtraCFGEdges(MachineBasicBlock &MBB, 
+                                 MachineBasicBlock *DestA,
+                                 MachineBasicBlock *DestB,
+                                 bool isCond, 
+                                 MachineFunction::iterator FallThru);
+
 FunctionPass *llvm::createBranchFoldingPass() { return new BranchFolder(); }
 
 /// RemoveDeadBlock - Remove the specified dead machine basic block from the
@@ -106,12 +112,21 @@ bool BranchFolder::runOnMachineFunction(MachineFunction &MF) {
   TII = MF.getTarget().getInstrInfo();
   if (!TII) return false;
 
+  // Fix CFG.  The later algorithms expect it to be right.
+  bool EverMadeChange = false;
+  for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; I++) {
+    MachineBasicBlock *MBB = I, *TBB = 0, *FBB = 0;
+    std::vector<MachineOperand> Cond;
+    if (!TII->AnalyzeBranch(*MBB, TBB, FBB, Cond))
+      EverMadeChange |= CorrectExtraCFGEdges(*MBB, TBB, FBB, 
+                        !Cond.empty(), next(I));
+  }
+
   RegInfo = MF.getTarget().getRegisterInfo();
   RS = RegInfo->requiresRegisterScavenging(MF) ? new RegScavenger() : NULL;
 
   MMI = getAnalysisToUpdate<MachineModuleInfo>();
 
-  bool EverMadeChange = false;
   bool MadeChangeThisIteration = true;
   while (MadeChangeThisIteration) {
     MadeChangeThisIteration = false;