X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FValueTracking.cpp;h=c51a719313f2a12ae7d000faa27eb86342f10697;hb=24d3b38a0a02a31f524aa73892e1558160ea70bc;hp=3a04f5eb869c8dccee19368374fd5b52f9a82348;hpb=a60832b0187642d01fd726dc766cd62587f6add0;p=oota-llvm.git

diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index 3a04f5eb869..c51a719313f 100644
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -509,12 +509,15 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask,
           ComputeMaskedBits(R, Mask2, KnownZero2, KnownOne2, TD, Depth+1);
           Mask2 = APInt::getLowBitsSet(BitWidth,
                                        KnownZero2.countTrailingOnes());
-          KnownOne2.clear();
-          KnownZero2.clear();
-          ComputeMaskedBits(L, Mask2, KnownZero2, KnownOne2, TD, Depth+1);
+
+          // We need to take the minimum number of known bits
+          APInt KnownZero3(KnownZero), KnownOne3(KnownOne);
+          ComputeMaskedBits(L, Mask2, KnownZero3, KnownOne3, TD, Depth+1);
+
           KnownZero = Mask &
                       APInt::getLowBitsSet(BitWidth,
-                                           KnownZero2.countTrailingOnes());
+                                           std::min(KnownZero2.countTrailingOnes(),
+                                                    KnownZero3.countTrailingOnes()));
           break;
         }
       }