jmp_bufs are this big on alpha.

llvm-svn: 30107
diff --git a/llvm/lib/Target/Alpha/AlphaISelLowering.cpp b/llvm/lib/Target/Alpha/AlphaISelLowering.cpp
index 9c44f55..fde5801 100644
--- a/llvm/lib/Target/Alpha/AlphaISelLowering.cpp
+++ b/llvm/lib/Target/Alpha/AlphaISelLowering.cpp
@@ -135,6 +135,9 @@
   addLegalFPImmediate(+0.0); //F31
   addLegalFPImmediate(-0.0); //-F31
 
+  setJumpBufSize(272);
+  setJumpBufAlignment(16);
+
   computeRegisterProperties();
 
   useITOF = TM.getSubtarget<AlphaSubtarget>().hasF2I();