Fix countLeadingZeros in the case that the bitwidth evenly divides the

word size. This fixes all reads of uninitialized data (buffer over read)
and makes APInt.cpp memory clean, per valgrind. The only remaining
problem is division in a few cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34483 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp
index a515366..c8ab2d7 100644 (file)
--- a/lib/Support/APInt.cpp
+++ b/lib/Support/APInt.cpp
@@ -726,7 +726,10 @@ uint32_t APInt::countLeadingZeros() const {
       }
     }
   }
-  return Count - (APINT_BITS_PER_WORD - (BitWidth % APINT_BITS_PER_WORD));
+  uint32_t remainder = BitWidth % APINT_BITS_PER_WORD;
+  if (remainder)
+    Count -= APINT_BITS_PER_WORD - remainder;
+  return Count;
 }
 
 /// countTrailingZeros - This function is a APInt version corresponding to