commit c714f1309049b2fd9e4ab68c8a7b480c63a4be0c
author David Greene <greened@obbligato.org> Mon Oct 27 23:24:03 2008 +0000
committer David Greene <greened@obbligato.org> Mon Oct 27 23:24:03 2008 +0000
tree 976bccac6fb2c9658f4361930ecfea3a51c5c08b
parent b3990d5e948769a16d4ee77dbdff8a2bed8fb126

Re-apply 55137 with fixes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58296 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/ValueTracking.cpp

diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index 3a04f5e..c51a719 100644
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -509,12 +509,15 @@
           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;
         }
       }