IR: Allow 32-bits for lines in debug location

Remove unnecessary restriction of 24-bits for line numbers in
`MDLocation`.

The rest of the debug info schema (with the exception of local
variables) uses 32-bits for line numbers.  As I introduce the
specialized nodes, it makes sense to canonicalize on one size or the
other.

llvm-svn: 228455
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index 8282017..ce55d95 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -538,21 +538,20 @@
     EXPECT_EQ(2u, L->getLine());
     EXPECT_EQ(7u, L->getColumn());
   }
-  unsigned U24 = 1u << 24;
   unsigned U16 = 1u << 16;
   {
-    MDLocation *L = MDLocation::get(Context, U24 - 1, U16 - 1, N);
-    EXPECT_EQ(U24 - 1, L->getLine());
+    MDLocation *L = MDLocation::get(Context, UINT32_MAX, U16 - 1, N);
+    EXPECT_EQ(UINT32_MAX, L->getLine());
     EXPECT_EQ(U16 - 1, L->getColumn());
   }
   {
-    MDLocation *L = MDLocation::get(Context, U24, U16, N);
-    EXPECT_EQ(0u, L->getLine());
+    MDLocation *L = MDLocation::get(Context, UINT32_MAX, U16, N);
+    EXPECT_EQ(UINT32_MAX, L->getLine());
     EXPECT_EQ(0u, L->getColumn());
   }
   {
-    MDLocation *L = MDLocation::get(Context, U24 + 1, U16 + 1, N);
-    EXPECT_EQ(0u, L->getLine());
+    MDLocation *L = MDLocation::get(Context, UINT32_MAX, U16 + 1, N);
+    EXPECT_EQ(UINT32_MAX, L->getLine());
     EXPECT_EQ(0u, L->getColumn());
   }
 }