Teach AsmPrinter how to print odd constants.

Fix an assertion when the compiler encounters big constants whose bit width is
not a multiple of 64-bits.
Although clang would never generate something like this, the backend should be
able to handle any legal IR.

<rdar://problem/13363576>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183544 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/X86/emit-big-cst.ll

@@ -0,0 +1,17 @@
+; RUN: llc -mtriple=x86_64-unknown-unknown < %s | FileCheck %s
+; Check assembly printing of odd constants.
+
+; CHECK: bigCst:
+; CHECK-NEXT: .quad 12713950999227904
+; CHECK-NEXT: .quad 26220
+; CHECK-NEXT: .size bigCst, 16
+
+@bigCst = internal constant i82 483673642326615442599424
+
+define void @accessBig(i64* %storage) {
+  %addr = bitcast i64* %storage to i82*
+  %bigLoadedCst = load volatile i82* @bigCst
+  %tmp = add i82 %bigLoadedCst, 1
+  store i82 %tmp, i82* %addr
+  ret void
+}