silence a release mode warning


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23868 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Alpha/AlphaISelPattern.cpp b/lib/Target/Alpha/AlphaISelPattern.cpp
index 2f04646..af9d29e 100644
--- a/lib/Target/Alpha/AlphaISelPattern.cpp
+++ b/lib/Target/Alpha/AlphaISelPattern.cpp
@@ -506,7 +506,7 @@
   unsigned Tmp1, Tmp2 = 0, Tmp3;
   unsigned Opc = 0;
   unsigned opcode = N.getOpcode();
-  int64_t SImm;
+  int64_t SImm = 0;
   uint64_t UImm;
 
   SDNode *Node = N.Val;