[llvm] [LV] Fix ScalarIVSteps vplan pattern matcher, remove m_CanonicalIV() (PR #138298)

[David Sherwood via llvm-commits]

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@@ -0,0 +1,46 @@
+//===- llvm/unittests/Transforms/Vectorize/VPlanPatternMatchTest.cpp ------===//
+//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "../lib/Transforms/Vectorize/VPlanPatternMatch.h"
+#include "../lib/Transforms/Vectorize/LoopVectorizationPlanner.h"
+#include "../lib/Transforms/Vectorize/VPlan.h"
+#include "../lib/Transforms/Vectorize/VPlanHelpers.h"
+#include "VPlanTestBase.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+
+namespace {
+using VPPatternMatchTest = VPlanTestBase;
+
+TEST_F(VPPatternMatchTest, ScalarIVSteps) {
+  VPlan &Plan = getPlan();
+  VPBasicBlock *VPBB = Plan.createVPBasicBlock("");
+  VPBuilder Builder(VPBB);
+
+  IntegerType *I64Ty = IntegerType::get(C, 64);
+  VPValue *StartV = Plan.getOrAddLiveIn(ConstantInt::get(I64Ty, 0));
+  auto *CanonicalIVPHI = new VPCanonicalIVPHIRecipe(StartV, DebugLoc());
+  Builder.insert(CanonicalIVPHI);
+
+  VPValue *Inc = Plan.getOrAddLiveIn(ConstantInt::get(I64Ty, 1));
+  VPValue *VF = &Plan.getVF();
+  VPValue *Steps = Builder.createScalarIVSteps(
+      Instruction::Add, nullptr, CanonicalIVPHI, Inc, VF, DebugLoc());
+
+  using namespace VPlanPatternMatch;
+
+  ASSERT_TRUE(match(Steps, m_ScalarIVSteps(m_Specific(CanonicalIVPHI),
+                                           m_SpecificInt(1), m_Specific(VF))));
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david-arm wrote:

Is it worth having an ASSERT_FALSE for a scalar IV steps with a step != 1?

https://github.com/llvm/llvm-project/pull/138298