Fix shift overflow bug that would occur when a field was a full 32-bits

in tblgen.  This is PR2827, thanks to Waldemar Knorr for tracking this
down.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57124 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 1 deletions

diff --git a/utils/TableGen/CodeEmitterGen.cpp b/utils/TableGen/CodeEmitterGen.cpp
index 62df686ea2..ae4a6aa445 100644
--- a/utils/TableGen/CodeEmitterGen.cpp
+++ b/utils/TableGen/CodeEmitterGen.cpp
@@ -191,7 +191,7 @@ void CodeEmitterGen::run(std::ostream &o) {
               gotOp = true;
             }
             
-            unsigned opMask = (1 << N) - 1;
+            unsigned opMask = ~0U >> (32-N);
             int opShift = beginVarBit - N + 1;
             opMask <<= opShift;
             opShift = beginInstBit - beginVarBit;