For PR1188:
Compute BitMask correctly.

Patch by Leo (wenwenti@hotmail.com).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34026 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/Interpreter/Execution.cpp b/lib/ExecutionEngine/Interpreter/Execution.cpp
index 565915b..fe80dfd 100644
--- a/lib/ExecutionEngine/Interpreter/Execution.cpp
+++ b/lib/ExecutionEngine/Interpreter/Execution.cpp
@@ -1307,7 +1307,7 @@
 
 #define INTEGER_ASSIGN(DEST, BITWIDTH, VAL)     \
   {                                             \
-    uint64_t Mask = (1ull << BITWIDTH) - 1;     \
+    uint64_t Mask = ~(uint64_t)(0ull) >> (64-BITWIDTH);     \
     if (BITWIDTH == 1) {                        \
       Dest.Int1Val = (bool) (VAL & Mask);       \
     } else if (BITWIDTH <= 8) {                 \