[llvm] [SPIR-V] Add SPIR-V structurizer (PR #97606)

[Michal Paszkowski via llvm-commits]

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@@ -0,0 +1,649 @@
+//===-- SPIRVStructurizer.cpp -----------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass adds the required OpSelection/OpLoop merge instructions to
+// generate valid SPIR-V.
+// This pass trims convergence intrinsics as those were only useful when
+// modifying the CFG during IR passes.
+//
+//===----------------------------------------------------------------------===//
+
+#include <stack>
+
+#include "Analysis/SPIRVConvergenceRegionAnalysis.h"
+#include "SPIRV.h"
+#include "SPIRVSubtarget.h"
+#include "SPIRVTargetMachine.h"
+#include "SPIRVUtils.h"
+#include "llvm/ADT/BreadthFirstIterator.h"
+#include "llvm/CodeGen/GlobalISel/GenericMachineInstrs.h"
+#include "llvm/CodeGen/IntrinsicLowering.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachinePostDominators.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/IntrinsicsSPIRV.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Transforms/Utils/LowerMemIntrinsics.h"
+
+using namespace llvm;
+using namespace SPIRV;
+
+namespace llvm {
+void initializeSPIRVStructurizerPass(PassRegistry &);
+}
+
+namespace {
+
+// Returns the exact convergence region in the tree defined by `Node` for which
+// `MBB` is the header, nullptr otherwise.
+const ConvergenceRegion *getRegionForHeader(const ConvergenceRegion *Node,
+                                            MachineBasicBlock *MBB) {
+  if (Node->Entry == MBB->getBasicBlock())
+    return Node;
+
+  for (auto *Child : Node->Children) {
+    const auto *CR = getRegionForHeader(Child, MBB);
+    if (CR != nullptr)
+      return CR;
+  }
+  return nullptr;
+}
+
+// Returns the MachineBasicBlock in `MF` matching `BB`, nullptr otherwise.
+MachineBasicBlock *getMachineBlockFor(MachineFunction &MF, BasicBlock *BB) {
+  for (auto &MBB : MF)
+    if (MBB.getBasicBlock() == BB)
+      return &MBB;
+  return nullptr;
+}
+
+// Gather all the successors of |BB|.
+// This function asserts if the terminator neither a branch, switch or return.
+std::unordered_set<BasicBlock *> gatherSuccessors(BasicBlock *BB) {
+  std::unordered_set<BasicBlock *> output;
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michalpaszkowski wrote:

Please start [variable names with upper case letter](https://llvm.org/docs/CodingStandards.html#id44).

https://github.com/llvm/llvm-project/pull/97606