Update prebuilt Clang to r416183b from Android.

https://android.googlesource.com/platform/prebuilts/clang/host/
linux-x86/+/06a71ddac05c22edb2d10b590e1769b3f8619bef

clang 12.0.5 (based on r416183b) from build 7284624.

Change-Id: I277a316abcf47307562d8b748b84870f31a72866
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/linux-x64/clang/include/polly/CodeGen/LoopGenerators.h b/linux-x64/clang/include/polly/CodeGen/LoopGenerators.h
new file mode 100644
index 0000000..09a0424
--- /dev/null
+++ b/linux-x64/clang/include/polly/CodeGen/LoopGenerators.h
@@ -0,0 +1,218 @@
+//===- LoopGenerators.h - IR helper to create loops -------------*- 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 file contains functions to create scalar and OpenMP parallel loops
+// as LLVM-IR.
+//
+//===----------------------------------------------------------------------===//
+#ifndef POLLY_LOOP_GENERATORS_H
+#define POLLY_LOOP_GENERATORS_H
+
+#include "polly/CodeGen/IRBuilder.h"
+#include "polly/Support/ScopHelper.h"
+#include "llvm/ADT/SetVector.h"
+
+namespace polly {
+using namespace llvm;
+
+/// General scheduling types of parallel OpenMP for loops.
+/// Initialization values taken from OpenMP's enum in kmp.h: sched_type.
+/// Currently, only 'static' scheduling may change from chunked to non-chunked.
+enum class OMPGeneralSchedulingType {
+  StaticChunked = 33,
+  StaticNonChunked = 34,
+  Dynamic = 35,
+  Guided = 36,
+  Runtime = 37
+};
+
+extern int PollyNumThreads;
+extern OMPGeneralSchedulingType PollyScheduling;
+extern int PollyChunkSize;
+
+/// Create a scalar do/for-style loop.
+///
+/// @param LowerBound         The starting value of the induction variable.
+/// @param UpperBound         The upper bound of the induction variable.
+/// @param Stride             The value by which the induction variable
+///                           is incremented.
+///
+/// @param Builder            The builder used to create the loop.
+/// @param P                  A pointer to the pass that uses this function.
+///                           It is used to update analysis information.
+/// @param LI                 The loop info for the current function
+/// @param DT                 The dominator tree we need to update
+/// @param ExitBlock          The block the loop will exit to.
+/// @param Predicate          The predicate used to generate the upper loop
+///                           bound.
+/// @param Annotator          This function can (optionally) take
+///                           a ScopAnnotator which
+///                           annotates loops and alias information in the SCoP.
+/// @param Parallel           If this loop should be marked parallel in
+///                           the Annotator.
+/// @param UseGuard           Create a guard in front of the header to check if
+///                           the loop is executed at least once, otherwise just
+///                           assume it.
+/// @param LoopVectDisabled   If the Loop vectorizer should be disabled for this
+///                           loop.
+///
+/// @return Value*    The newly created induction variable for this loop.
+Value *createLoop(Value *LowerBound, Value *UpperBound, Value *Stride,
+                  PollyIRBuilder &Builder, LoopInfo &LI, DominatorTree &DT,
+                  BasicBlock *&ExitBlock, ICmpInst::Predicate Predicate,
+                  ScopAnnotator *Annotator = NULL, bool Parallel = false,
+                  bool UseGuard = true, bool LoopVectDisabled = false);
+
+/// The ParallelLoopGenerator allows to create parallelized loops
+///
+/// To parallelize a loop, we perform the following steps:
+///   o  Generate a subfunction which will hold the loop body.
+///   o  Create a struct to hold all outer values needed in the loop body.
+///   o  Create calls to a runtime library to achieve the actual parallelism.
+///      These calls will spawn and join threads, define how the work (here the
+///      iterations) are distributed between them and make sure each has access
+///      to the struct holding all needed values.
+///
+/// At the moment we support only one parallel runtime, OpenMP.
+///
+/// If we parallelize the outer loop of the following loop nest,
+///
+///   S0;
+///   for (int i = 0; i < N; i++)
+///     for (int j = 0; j < M; j++)
+///       S1(i, j);
+///   S2;
+///
+/// we will generate the following code (with different runtime function names):
+///
+///   S0;
+///   auto *values = storeValuesIntoStruct();
+///   // Execute subfunction with multiple threads
+///   spawn_threads(subfunction, values);
+///   join_threads();
+///   S2;
+///
+///  // This function is executed in parallel by different threads
+///   void subfunction(values) {
+///     while (auto *WorkItem = getWorkItem()) {
+///       int LB = WorkItem.begin();
+///       int UB = WorkItem.end();
+///       for (int i = LB; i < UB; i++)
+///         for (int j = 0; j < M; j++)
+///           S1(i, j);
+///     }
+///     cleanup_thread();
+///   }
+class ParallelLoopGenerator {
+public:
+  /// Create a parallel loop generator for the current function.
+  ParallelLoopGenerator(PollyIRBuilder &Builder, LoopInfo &LI,
+                        DominatorTree &DT, const DataLayout &DL)
+      : Builder(Builder), LI(LI), DT(DT),
+        LongType(
+            Type::getIntNTy(Builder.getContext(), DL.getPointerSizeInBits())),
+        M(Builder.GetInsertBlock()->getParent()->getParent()) {}
+
+  virtual ~ParallelLoopGenerator() {}
+
+  /// Create a parallel loop.
+  ///
+  /// This function is the main function to automatically generate a parallel
+  /// loop with all its components.
+  ///
+  /// @param LB        The lower bound for the loop we parallelize.
+  /// @param UB        The upper bound for the loop we parallelize.
+  /// @param Stride    The stride of the loop we parallelize.
+  /// @param Values    A set of LLVM-IR Values that should be available in
+  ///                  the new loop body.
+  /// @param VMap      A map to allow outside access to the new versions of
+  ///                  the values in @p Values.
+  /// @param LoopBody  A pointer to an iterator that is set to point to the
+  ///                  body of the created loop. It should be used to insert
+  ///                  instructions that form the actual loop body.
+  ///
+  /// @return The newly created induction variable for this loop.
+  Value *createParallelLoop(Value *LB, Value *UB, Value *Stride,
+                            SetVector<Value *> &Values, ValueMapT &VMap,
+                            BasicBlock::iterator *LoopBody);
+
+protected:
+  /// The IR builder we use to create instructions.
+  PollyIRBuilder &Builder;
+
+  /// The loop info of the current function we need to update.
+  LoopInfo &LI;
+
+  /// The dominance tree of the current function we need to update.
+  DominatorTree &DT;
+
+  /// The type of a "long" on this hardware used for backend calls.
+  Type *LongType;
+
+  /// The current module
+  Module *M;
+
+public:
+  /// Create a struct for all @p Values and store them in there.
+  ///
+  /// @param Values The values which should be stored in the struct.
+  ///
+  /// @return The created struct.
+  AllocaInst *storeValuesIntoStruct(SetVector<Value *> &Values);
+
+  /// Extract all values from the @p Struct and construct the mapping.
+  ///
+  /// @param Values The values which were stored in the struct.
+  /// @param Struct The struct holding all the values in @p Values.
+  /// @param VMap   A map to associate every element of @p Values with the
+  ///               new llvm value loaded from the @p Struct.
+  void extractValuesFromStruct(SetVector<Value *> Values, Type *Ty,
+                               Value *Struct, ValueMapT &VMap);
+
+  /// Create the definition of the parallel subfunction.
+  ///
+  /// @return A pointer to the subfunction.
+  Function *createSubFnDefinition();
+
+  /// Create the runtime library calls for spawn and join of the worker threads.
+  /// Additionally, places a call to the specified subfunction.
+  ///
+  /// @param SubFn      The subfunction which holds the loop body.
+  /// @param SubFnParam The parameter for the subfunction (basically the struct
+  ///                   filled with the outside values).
+  /// @param LB         The lower bound for the loop we parallelize.
+  /// @param UB         The upper bound for the loop we parallelize.
+  /// @param Stride     The stride of the loop we parallelize.
+  virtual void deployParallelExecution(Function *SubFn, Value *SubFnParam,
+                                       Value *LB, Value *UB, Value *Stride) = 0;
+
+  /// Prepare the definition of the parallel subfunction.
+  /// Creates the argument list and names them (as well as the subfunction).
+  ///
+  /// @param F A pointer to the (parallel) subfunction's parent function.
+  ///
+  /// @return The pointer to the (parallel) subfunction.
+  virtual Function *prepareSubFnDefinition(Function *F) const = 0;
+
+  /// Create the parallel subfunction.
+  ///
+  /// @param Stride The induction variable increment.
+  /// @param Struct A struct holding all values in @p Values.
+  /// @param Values A set of LLVM-IR Values that should be available in
+  ///               the new loop body.
+  /// @param VMap   A map to allow outside access to the new versions of
+  ///               the values in @p Values.
+  /// @param SubFn  The newly created subfunction is returned here.
+  ///
+  /// @return The newly created induction variable.
+  virtual std::tuple<Value *, Function *>
+  createSubFn(Value *Stride, AllocaInst *Struct, SetVector<Value *> UsedValues,
+              ValueMapT &VMap) = 0;
+};
+} // end namespace polly
+#endif