[llvm-commits] [llvm] r126378 - in /llvm/trunk: include/llvm/CodeGen/FunctionLoweringInfo.h lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

[Cameron Zwarich]

Author: zwarich
Date: Thu Feb 24 04:00:16 2011
New Revision: 126378

URL: http://llvm.org/viewvc/llvm-project?rev=126378&view=rev
Log:
Add a mechanism for invalidating the LiveOutInfo of a PHI, and use it whenever
a block is visited before all of its predecessors.

Modified:
    llvm/trunk/include/llvm/CodeGen/FunctionLoweringInfo.h
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

Modified: llvm/trunk/include/llvm/CodeGen/FunctionLoweringInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/FunctionLoweringInfo.h?rev=126378&r1=126377&r2=126378&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/FunctionLoweringInfo.h (original)
+++ llvm/trunk/include/llvm/CodeGen/FunctionLoweringInfo.h Thu Feb 24 04:00:16 2011
@@ -101,9 +101,11 @@
 #endif
 
   struct LiveOutInfo {
-    unsigned NumSignBits;
+    unsigned NumSignBits : 31;
+    bool IsValid : 1;
     APInt KnownOne, KnownZero;
-    LiveOutInfo() : NumSignBits(0), KnownOne(1, 0), KnownZero(1, 0) {}
+    LiveOutInfo() : NumSignBits(0), IsValid(true), KnownOne(1, 0),
+                    KnownZero(1, 0) {}
   };
 
   /// VisitedBBs - The set of basic blocks visited thus far by instruction
@@ -149,7 +151,12 @@
   const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg) {
     if (!LiveOutRegInfo.inBounds(Reg))
       return NULL;
-    return &LiveOutRegInfo[Reg];
+
+    const LiveOutInfo *LOI = &LiveOutRegInfo[Reg];
+    if (!LOI->IsValid)
+      return NULL;
+
+    return LOI;
   }
 
   /// AddLiveOutRegInfo - Adds LiveOutInfo for a register.
@@ -166,6 +173,14 @@
     LOI.KnownZero = KnownZero;
   }
 
+  /// InvalidatePHILiveOutRegInfo - Invalidates a PHI's LiveOutInfo, to be
+  /// called when a block is visited before all of its predecessors.
+  void InvalidatePHILiveOutRegInfo(const PHINode *PN) {
+    unsigned Reg = ValueMap[PN];
+    LiveOutRegInfo.grow(Reg);
+    LiveOutRegInfo[Reg].IsValid = false;
+  }
+
   /// setByValArgumentFrameIndex - Record frame index for the byval
   /// argument.
   void setByValArgumentFrameIndex(const Argument *A, int FI);

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp?rev=126378&r1=126377&r2=126378&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp Thu Feb 24 04:00:16 2011
@@ -832,8 +832,25 @@
     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();