From 2c5e9d71aba3b1a85f07c08d2c09d40b8547264b Mon Sep 17 00:00:00 2001
From: dim <dim@FreeBSD.org>
Date: Thu, 3 May 2012 16:50:55 +0000
Subject: Vendor import of llvm release_31 branch r155985:
 http://llvm.org/svn/llvm-project/llvm/branches/release_31@155985

---
 lib/Analysis/ConstantFolding.cpp | 14 +++++++++++---
 lib/Analysis/ScalarEvolution.cpp |  2 +-
 lib/Analysis/ValueTracking.cpp   |  2 +-
 3 files changed, 13 insertions(+), 5 deletions(-)

(limited to 'lib/Analysis')

diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index 7a0a4e1e..783c32e 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -681,6 +681,7 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef<Constant *> Ops,
   // This makes it easy to determine if the getelementptr is "inbounds".
   // Also, this helps GlobalOpt do SROA on GlobalVariables.
   Type *Ty = Ptr->getType();
+  assert(Ty->isPointerTy() && "Forming regular GEP of non-pointer type");
   SmallVector<Constant*, 32> NewIdxs;
   do {
     if (SequentialType *ATy = dyn_cast<SequentialType>(Ty)) {
@@ -711,10 +712,17 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef<Constant *> Ops,
       }
       Ty = ATy->getElementType();
     } else if (StructType *STy = dyn_cast<StructType>(Ty)) {
-      // Determine which field of the struct the offset points into. The
-      // getZExtValue is at least as safe as the StructLayout API because we
-      // know the offset is within the struct at this point.
+      // If we end up with an offset that isn't valid for this struct type, we
+      // can't re-form this GEP in a regular form, so bail out. The pointer
+      // operand likely went through casts that are necessary to make the GEP
+      // sensible.
       const StructLayout &SL = *TD->getStructLayout(STy);
+      if (Offset.uge(SL.getSizeInBytes()))
+        break;
+
+      // Determine which field of the struct the offset points into. The
+      // getZExtValue is fine as we've already ensured that the offset is
+      // within the range representable by the StructLayout API.
       unsigned ElIdx = SL.getElementContainingOffset(Offset.getZExtValue());
       NewIdxs.push_back(ConstantInt::get(Type::getInt32Ty(Ty->getContext()),
                                          ElIdx));
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 1d55642..205227c 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -3187,7 +3187,7 @@ const SCEV *ScalarEvolution::createNodeForGEP(GEPOperator *GEP) {
 
   // Add the total offset from all the GEP indices to the base.
   return getAddExpr(BaseS, TotalOffset,
-                    isInBounds ? SCEV::FlagNUW : SCEV::FlagAnyWrap);
+                    isInBounds ? SCEV::FlagNSW : SCEV::FlagAnyWrap);
 }
 
 /// GetMinTrailingZeros - Determine the minimum number of zero bits that S is
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index a430f62..1418e01 100644
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -564,7 +564,7 @@ void llvm::ComputeMaskedBits(Value *V, APInt &KnownZero, APInt &KnownOne,
                         Depth+1);
       // If it's known zero, our sign bit is also zero.
       if (LHSKnownZero.isNegative())
-        KnownZero |= LHSKnownZero;
+        KnownZero.setBit(BitWidth - 1);
     }
 
     break;
-- 
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