[SVE][IR] Scalable Vector size queries and IR instruction support

* Adds a TypeSize struct to represent the known minimum size of a type
  along with a flag to indicate that the runtime size is a integer multiple
  of that size
* Converts existing size query functions from Type.h and DataLayout.h to
  return a TypeSize result
* Adds convenience methods (including a transparent conversion operator
  to uint64_t) so that most existing code 'just works' as if the return
  values were still scalars.
* Uses the new size queries along with ElementCount to ensure that all
  supported instructions used with scalable vectors can be constructed
  in IR.

Reviewers: hfinkel, lattner, rkruppe, greened, rovka, rengolin, sdesmalen

Reviewed By: rovka, sdesmalen

Differential Revision: https://reviews.llvm.org/D53137

llvm-svn: 374042
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 707db04..c058b4b 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -2073,8 +2073,8 @@
 
       // Update largest vector width for any vector types.
       if (auto *VT = dyn_cast<llvm::VectorType>(ResultRegTypes.back()))
-        LargestVectorWidth = std::max(LargestVectorWidth,
-                                      VT->getPrimitiveSizeInBits());
+        LargestVectorWidth = std::max((uint64_t)LargestVectorWidth,
+                                   VT->getPrimitiveSizeInBits().getFixedSize());
     } else {
       ArgTypes.push_back(Dest.getAddress().getType());
       Args.push_back(Dest.getPointer());
@@ -2098,8 +2098,8 @@
 
       // Update largest vector width for any vector types.
       if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
-        LargestVectorWidth = std::max(LargestVectorWidth,
-                                      VT->getPrimitiveSizeInBits());
+        LargestVectorWidth = std::max((uint64_t)LargestVectorWidth,
+                                   VT->getPrimitiveSizeInBits().getFixedSize());
       if (Info.allowsRegister())
         InOutConstraints += llvm::utostr(i);
       else
@@ -2185,8 +2185,8 @@
 
     // Update largest vector width for any vector types.
     if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
-      LargestVectorWidth = std::max(LargestVectorWidth,
-                                    VT->getPrimitiveSizeInBits());
+      LargestVectorWidth = std::max((uint64_t)LargestVectorWidth,
+                                   VT->getPrimitiveSizeInBits().getFixedSize());
 
     ArgTypes.push_back(Arg->getType());
     Args.push_back(Arg);