From 324a24f6aa5d6752c57c39e1e19f00b8c8a4ceec Mon Sep 17 00:00:00 2001
From: Cameron Zwarich <zwarich@apple.com>
Date: Thu, 24 Feb 2011 10:00:16 +0000
Subject: Add a mechanism for invalidating the LiveOutInfo of a PHI, and use it
 whenever a block is visited before all of its predecessors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126378 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

(limited to 'lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp')

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 9d3f5bc..d540063 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -832,8 +832,25 @@ void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
     CheckLineNumbers(LLVMBB);
 #endif
 
-    if (OptLevel != CodeGenOpt::None)
+    if (OptLevel != CodeGenOpt::None) {
+      bool AllPredsVisited = true;
+      for (const_pred_iterator PI = pred_begin(LLVMBB), PE = pred_end(LLVMBB);
+           PI != PE; ++PI) {
+        if (!FuncInfo->VisitedBBs.count(*PI)) {
+          AllPredsVisited = false;
+          break;
+        }
+      }
+
+      if (!AllPredsVisited) {
+        for (BasicBlock::const_iterator I = LLVMBB->begin(), E = LLVMBB->end();
+             I != E && isa<PHINode>(I); ++I) {
+          FuncInfo->InvalidatePHILiveOutRegInfo(cast<PHINode>(I));
+        }
+      }
+
       FuncInfo->VisitedBBs.insert(LLVMBB);
+    }
 
     FuncInfo->MBB = FuncInfo->MBBMap[LLVMBB];
     FuncInfo->InsertPt = FuncInfo->MBB->getFirstNonPHI();
-- 
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