[MVT][SVE] Scalable vector MVTs (3/3)

Adds MVT::ElementCount to represent the length of a
vector which may be scalable, then adds helper functions
that work with it.

Patch by Graham Hunter.

Differential Revision: https://reviews.llvm.org/D32019

llvm-svn: 300842
diff --git a/llvm/unittests/CodeGen/ScalableVectorMVTsTest.cpp b/llvm/unittests/CodeGen/ScalableVectorMVTsTest.cpp
new file mode 100644
index 0000000..a22c872
--- /dev/null
+++ b/llvm/unittests/CodeGen/ScalableVectorMVTsTest.cpp
@@ -0,0 +1,88 @@
+//===-------- llvm/unittest/CodeGen/ScalableVectorMVTsTest.cpp ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/MachineValueType.h"
+#include "llvm/CodeGen/ValueTypes.h"
+#include "llvm/IR/LLVMContext.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+TEST(ScalableVectorMVTsTest, IntegerMVTs) {
+  for (auto VecTy : MVT::integer_scalable_vector_valuetypes()) {
+    ASSERT_TRUE(VecTy.isValid());
+    ASSERT_TRUE(VecTy.isInteger());
+    ASSERT_TRUE(VecTy.isVector());
+    ASSERT_TRUE(VecTy.isScalableVector());
+    ASSERT_TRUE(VecTy.getScalarType().isValid());
+
+    ASSERT_FALSE(VecTy.isFloatingPoint());
+  }
+}
+
+TEST(ScalableVectorMVTsTest, FloatMVTs) {
+  for (auto VecTy : MVT::fp_scalable_vector_valuetypes()) {
+    ASSERT_TRUE(VecTy.isValid());
+    ASSERT_TRUE(VecTy.isFloatingPoint());
+    ASSERT_TRUE(VecTy.isVector());
+    ASSERT_TRUE(VecTy.isScalableVector());
+    ASSERT_TRUE(VecTy.getScalarType().isValid());
+
+    ASSERT_FALSE(VecTy.isInteger());
+  }
+}
+
+TEST(ScalableVectorMVTsTest, HelperFuncs) {
+  LLVMContext Ctx;
+
+  // Create with scalable flag
+  EVT Vnx4i32 = EVT::getVectorVT(Ctx, MVT::i32, 4, /*Scalable=*/true);
+  ASSERT_TRUE(Vnx4i32.isScalableVector());
+
+  // Create with separate MVT::ElementCount
+  auto EltCnt = MVT::ElementCount(2, true);
+  EVT Vnx2i32 = EVT::getVectorVT(Ctx, MVT::i32, EltCnt);
+  ASSERT_TRUE(Vnx2i32.isScalableVector());
+
+  // Create with inline MVT::ElementCount
+  EVT Vnx2i64 = EVT::getVectorVT(Ctx, MVT::i64, {2, true});
+  ASSERT_TRUE(Vnx2i64.isScalableVector());
+
+  // Check that changing scalar types/element count works
+  EXPECT_EQ(Vnx2i32.widenIntegerVectorElementType(Ctx), Vnx2i64);
+  EXPECT_EQ(Vnx4i32.getHalfNumVectorElementsVT(Ctx), Vnx2i32);
+
+  // Check that overloaded '*' and '/' operators work
+  EXPECT_EQ(EVT::getVectorVT(Ctx, MVT::i64, EltCnt * 2), MVT::nxv4i64);
+  EXPECT_EQ(EVT::getVectorVT(Ctx, MVT::i64, EltCnt / 2), MVT::nxv1i64);
+
+  // Check that float->int conversion works
+  EVT Vnx2f64 = EVT::getVectorVT(Ctx, MVT::f64, {2, true});
+  EXPECT_EQ(Vnx2f64.changeTypeToInteger(), Vnx2i64);
+
+  // Check fields inside MVT::ElementCount
+  EltCnt = Vnx4i32.getVectorElementCount();
+  EXPECT_EQ(EltCnt.Min, 4);
+  ASSERT_TRUE(EltCnt.Scalable);
+
+  // Check that fixed-length vector types aren't scalable.
+  EVT V8i32 = EVT::getVectorVT(Ctx, MVT::i32, 8);
+  ASSERT_FALSE(V8i32.isScalableVector());
+  EVT V4f64 = EVT::getVectorVT(Ctx, MVT::f64, {4, false});
+  ASSERT_FALSE(V4f64.isScalableVector());
+
+  // Check that MVT::ElementCount works for fixed-length types.
+  EltCnt = V8i32.getVectorElementCount();
+  EXPECT_EQ(EltCnt.Min, 8);
+  ASSERT_FALSE(EltCnt.Scalable);
+}
+
+}