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.

llvm-svn: 34483

1 files changed, 4 insertions, 1 deletions

diff --git a/llvm/lib/Support/APInt.cpp b/llvm/lib/Support/APInt.cpp
index a515366db21..c8ab2d762b6 100644
--- a/llvm/lib/Support/APInt.cpp
+++ b/llvm/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