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/llvm/CodeGen/GlobalISel/CombinerHelper.h b/linux-x64/clang/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
index 0c50c9c..0d240e9 100644
--- a/linux-x64/clang/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
+++ b/linux-x64/clang/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
@@ -17,16 +17,24 @@
 #ifndef LLVM_CODEGEN_GLOBALISEL_COMBINER_HELPER_H
 #define LLVM_CODEGEN_GLOBALISEL_COMBINER_HELPER_H
 
+#include "llvm/ADT/APFloat.h"
 #include "llvm/CodeGen/LowLevelType.h"
 #include "llvm/CodeGen/Register.h"
+#include "llvm/Support/Alignment.h"
 
 namespace llvm {
 
 class GISelChangeObserver;
 class MachineIRBuilder;
+class MachineInstrBuilder;
 class MachineRegisterInfo;
 class MachineInstr;
 class MachineOperand;
+class GISelKnownBits;
+class MachineDominatorTree;
+class LegalizerInfo;
+struct LegalityQuery;
+class TargetLowering;
 
 struct PreferredTuple {
   LLT Ty;                // The result type of the extend.
@@ -34,13 +42,73 @@
   MachineInstr *MI;
 };
 
+struct IndexedLoadStoreMatchInfo {
+  Register Addr;
+  Register Base;
+  Register Offset;
+  bool IsPre;
+};
+
+struct PtrAddChain {
+  int64_t Imm;
+  Register Base;
+};
+
+struct RegisterImmPair {
+  Register Reg;
+  int64_t Imm;
+};
+
+struct ShiftOfShiftedLogic {
+  MachineInstr *Logic;
+  MachineInstr *Shift2;
+  Register LogicNonShiftReg;
+  uint64_t ValSum;
+};
+
+using OperandBuildSteps =
+    SmallVector<std::function<void(MachineInstrBuilder &)>, 4>;
+struct InstructionBuildSteps {
+  unsigned Opcode = 0;          /// The opcode for the produced instruction.
+  OperandBuildSteps OperandFns; /// Operands to be added to the instruction.
+  InstructionBuildSteps() = default;
+  InstructionBuildSteps(unsigned Opcode, const OperandBuildSteps &OperandFns)
+      : Opcode(Opcode), OperandFns(OperandFns) {}
+};
+
+struct InstructionStepsMatchInfo {
+  /// Describes instructions to be built during a combine.
+  SmallVector<InstructionBuildSteps, 2> InstrsToBuild;
+  InstructionStepsMatchInfo() = default;
+  InstructionStepsMatchInfo(
+      std::initializer_list<InstructionBuildSteps> InstrsToBuild)
+      : InstrsToBuild(InstrsToBuild) {}
+};
+
 class CombinerHelper {
+protected:
   MachineIRBuilder &Builder;
   MachineRegisterInfo &MRI;
   GISelChangeObserver &Observer;
+  GISelKnownBits *KB;
+  MachineDominatorTree *MDT;
+  const LegalizerInfo *LI;
 
 public:
-  CombinerHelper(GISelChangeObserver &Observer, MachineIRBuilder &B);
+  CombinerHelper(GISelChangeObserver &Observer, MachineIRBuilder &B,
+                 GISelKnownBits *KB = nullptr,
+                 MachineDominatorTree *MDT = nullptr,
+                 const LegalizerInfo *LI = nullptr);
+
+  GISelKnownBits *getKnownBits() const {
+    return KB;
+  }
+
+  const TargetLowering &getTargetLowering() const;
+
+  /// \return true if the combine is running prior to legalization, or if \p
+  /// Query is legal on the target.
+  bool isLegalOrBeforeLegalizer(const LegalityQuery &Query) const;
 
   /// MachineRegisterInfo::replaceRegWith() and inform the observer of the changes
   void replaceRegWith(MachineRegisterInfo &MRI, Register FromReg, Register ToReg) const;
@@ -56,18 +124,381 @@
   bool matchCombineCopy(MachineInstr &MI);
   void applyCombineCopy(MachineInstr &MI);
 
+  /// Returns true if \p DefMI precedes \p UseMI or they are the same
+  /// instruction. Both must be in the same basic block.
+  bool isPredecessor(const MachineInstr &DefMI, const MachineInstr &UseMI);
+
+  /// Returns true if \p DefMI dominates \p UseMI. By definition an
+  /// instruction dominates itself.
+  ///
+  /// If we haven't been provided with a MachineDominatorTree during
+  /// construction, this function returns a conservative result that tracks just
+  /// a single basic block.
+  bool dominates(const MachineInstr &DefMI, const MachineInstr &UseMI);
+
   /// If \p MI is extend that consumes the result of a load, try to combine it.
   /// Returns true if MI changed.
   bool tryCombineExtendingLoads(MachineInstr &MI);
   bool matchCombineExtendingLoads(MachineInstr &MI, PreferredTuple &MatchInfo);
   void applyCombineExtendingLoads(MachineInstr &MI, PreferredTuple &MatchInfo);
 
-  bool matchCombineBr(MachineInstr &MI);
-  bool tryCombineBr(MachineInstr &MI);
+  /// Combine \p MI into a pre-indexed or post-indexed load/store operation if
+  /// legal and the surrounding code makes it useful.
+  bool tryCombineIndexedLoadStore(MachineInstr &MI);
+  bool matchCombineIndexedLoadStore(MachineInstr &MI, IndexedLoadStoreMatchInfo &MatchInfo);
+  void applyCombineIndexedLoadStore(MachineInstr &MI, IndexedLoadStoreMatchInfo &MatchInfo);
+
+  bool matchSextTruncSextLoad(MachineInstr &MI);
+  bool applySextTruncSextLoad(MachineInstr &MI);
+
+  /// Match sext_inreg(load p), imm -> sextload p
+  bool matchSextInRegOfLoad(MachineInstr &MI, std::tuple<Register, unsigned> &MatchInfo);
+  bool applySextInRegOfLoad(MachineInstr &MI, std::tuple<Register, unsigned> &MatchInfo);
+
+  /// If a brcond's true block is not the fallthrough, make it so by inverting
+  /// the condition and swapping operands.
+  bool matchOptBrCondByInvertingCond(MachineInstr &MI);
+  void applyOptBrCondByInvertingCond(MachineInstr &MI);
+
+  /// If \p MI is G_CONCAT_VECTORS, try to combine it.
+  /// Returns true if MI changed.
+  /// Right now, we support:
+  /// - concat_vector(undef, undef) => undef
+  /// - concat_vector(build_vector(A, B), build_vector(C, D)) =>
+  ///   build_vector(A, B, C, D)
+  ///
+  /// \pre MI.getOpcode() == G_CONCAT_VECTORS.
+  bool tryCombineConcatVectors(MachineInstr &MI);
+  /// Check if the G_CONCAT_VECTORS \p MI is undef or if it
+  /// can be flattened into a build_vector.
+  /// In the first case \p IsUndef will be true.
+  /// In the second case \p Ops will contain the operands needed
+  /// to produce the flattened build_vector.
+  ///
+  /// \pre MI.getOpcode() == G_CONCAT_VECTORS.
+  bool matchCombineConcatVectors(MachineInstr &MI, bool &IsUndef,
+                                 SmallVectorImpl<Register> &Ops);
+  /// Replace \p MI with a flattened build_vector with \p Ops or an
+  /// implicit_def if IsUndef is true.
+  void applyCombineConcatVectors(MachineInstr &MI, bool IsUndef,
+                                 const ArrayRef<Register> Ops);
+
+  /// Try to combine G_SHUFFLE_VECTOR into G_CONCAT_VECTORS.
+  /// Returns true if MI changed.
+  ///
+  /// \pre MI.getOpcode() == G_SHUFFLE_VECTOR.
+  bool tryCombineShuffleVector(MachineInstr &MI);
+  /// Check if the G_SHUFFLE_VECTOR \p MI can be replaced by a
+  /// concat_vectors.
+  /// \p Ops will contain the operands needed to produce the flattened
+  /// concat_vectors.
+  ///
+  /// \pre MI.getOpcode() == G_SHUFFLE_VECTOR.
+  bool matchCombineShuffleVector(MachineInstr &MI,
+                                 SmallVectorImpl<Register> &Ops);
+  /// Replace \p MI with a concat_vectors with \p Ops.
+  void applyCombineShuffleVector(MachineInstr &MI,
+                                 const ArrayRef<Register> Ops);
+
+  /// Optimize memcpy intrinsics et al, e.g. constant len calls.
+  /// /p MaxLen if non-zero specifies the max length of a mem libcall to inline.
+  ///
+  /// For example (pre-indexed):
+  ///
+  ///     $addr = G_PTR_ADD $base, $offset
+  ///     [...]
+  ///     $val = G_LOAD $addr
+  ///     [...]
+  ///     $whatever = COPY $addr
+  ///
+  /// -->
+  ///
+  ///     $val, $addr = G_INDEXED_LOAD $base, $offset, 1 (IsPre)
+  ///     [...]
+  ///     $whatever = COPY $addr
+  ///
+  /// or (post-indexed):
+  ///
+  ///     G_STORE $val, $base
+  ///     [...]
+  ///     $addr = G_PTR_ADD $base, $offset
+  ///     [...]
+  ///     $whatever = COPY $addr
+  ///
+  /// -->
+  ///
+  ///     $addr = G_INDEXED_STORE $val, $base, $offset
+  ///     [...]
+  ///     $whatever = COPY $addr
+  bool tryCombineMemCpyFamily(MachineInstr &MI, unsigned MaxLen = 0);
+
+  bool matchPtrAddImmedChain(MachineInstr &MI, PtrAddChain &MatchInfo);
+  bool applyPtrAddImmedChain(MachineInstr &MI, PtrAddChain &MatchInfo);
+
+  /// Fold (shift (shift base, x), y) -> (shift base (x+y))
+  bool matchShiftImmedChain(MachineInstr &MI, RegisterImmPair &MatchInfo);
+  bool applyShiftImmedChain(MachineInstr &MI, RegisterImmPair &MatchInfo);
+
+  /// If we have a shift-by-constant of a bitwise logic op that itself has a
+  /// shift-by-constant operand with identical opcode, we may be able to convert
+  /// that into 2 independent shifts followed by the logic op.
+  bool matchShiftOfShiftedLogic(MachineInstr &MI,
+                                ShiftOfShiftedLogic &MatchInfo);
+  bool applyShiftOfShiftedLogic(MachineInstr &MI,
+                                ShiftOfShiftedLogic &MatchInfo);
+
+  /// Transform a multiply by a power-of-2 value to a left shift.
+  bool matchCombineMulToShl(MachineInstr &MI, unsigned &ShiftVal);
+  bool applyCombineMulToShl(MachineInstr &MI, unsigned &ShiftVal);
+
+  // Transform a G_SHL with an extended source into a narrower shift if
+  // possible.
+  bool matchCombineShlOfExtend(MachineInstr &MI, RegisterImmPair &MatchData);
+  bool applyCombineShlOfExtend(MachineInstr &MI,
+                               const RegisterImmPair &MatchData);
+
+  /// Reduce a shift by a constant to an unmerge and a shift on a half sized
+  /// type. This will not produce a shift smaller than \p TargetShiftSize.
+  bool matchCombineShiftToUnmerge(MachineInstr &MI, unsigned TargetShiftSize,
+                                 unsigned &ShiftVal);
+  bool applyCombineShiftToUnmerge(MachineInstr &MI, const unsigned &ShiftVal);
+  bool tryCombineShiftToUnmerge(MachineInstr &MI, unsigned TargetShiftAmount);
+
+  /// Transform <ty,...> G_UNMERGE(G_MERGE ty X, Y, Z) -> ty X, Y, Z.
+  bool
+  matchCombineUnmergeMergeToPlainValues(MachineInstr &MI,
+                                        SmallVectorImpl<Register> &Operands);
+  bool
+  applyCombineUnmergeMergeToPlainValues(MachineInstr &MI,
+                                        SmallVectorImpl<Register> &Operands);
+
+  /// Transform G_UNMERGE Constant -> Constant1, Constant2, ...
+  bool matchCombineUnmergeConstant(MachineInstr &MI,
+                                   SmallVectorImpl<APInt> &Csts);
+  bool applyCombineUnmergeConstant(MachineInstr &MI,
+                                   SmallVectorImpl<APInt> &Csts);
+
+  /// Transform X, Y<dead> = G_UNMERGE Z -> X = G_TRUNC Z.
+  bool matchCombineUnmergeWithDeadLanesToTrunc(MachineInstr &MI);
+  bool applyCombineUnmergeWithDeadLanesToTrunc(MachineInstr &MI);
+
+  /// Transform X, Y = G_UNMERGE(G_ZEXT(Z)) -> X = G_ZEXT(Z); Y = G_CONSTANT 0
+  bool matchCombineUnmergeZExtToZExt(MachineInstr &MI);
+  bool applyCombineUnmergeZExtToZExt(MachineInstr &MI);
+
+  /// Transform fp_instr(cst) to constant result of the fp operation.
+  bool matchCombineConstantFoldFpUnary(MachineInstr &MI,
+                                       Optional<APFloat> &Cst);
+  bool applyCombineConstantFoldFpUnary(MachineInstr &MI,
+                                       Optional<APFloat> &Cst);
+
+  /// Transform IntToPtr(PtrToInt(x)) to x if cast is in the same address space.
+  bool matchCombineI2PToP2I(MachineInstr &MI, Register &Reg);
+  bool applyCombineI2PToP2I(MachineInstr &MI, Register &Reg);
+
+  /// Transform PtrToInt(IntToPtr(x)) to x.
+  bool matchCombineP2IToI2P(MachineInstr &MI, Register &Reg);
+  bool applyCombineP2IToI2P(MachineInstr &MI, Register &Reg);
+
+  /// Transform G_ADD (G_PTRTOINT x), y -> G_PTRTOINT (G_PTR_ADD x, y)
+  /// Transform G_ADD y, (G_PTRTOINT x) -> G_PTRTOINT (G_PTR_ADD x, y)
+  bool matchCombineAddP2IToPtrAdd(MachineInstr &MI,
+                                  std::pair<Register, bool> &PtrRegAndCommute);
+  bool applyCombineAddP2IToPtrAdd(MachineInstr &MI,
+                                  std::pair<Register, bool> &PtrRegAndCommute);
+
+  // Transform G_PTR_ADD (G_PTRTOINT C1), C2 -> C1 + C2
+  bool matchCombineConstPtrAddToI2P(MachineInstr &MI, int64_t &NewCst);
+  bool applyCombineConstPtrAddToI2P(MachineInstr &MI, int64_t &NewCst);
+
+  /// Transform anyext(trunc(x)) to x.
+  bool matchCombineAnyExtTrunc(MachineInstr &MI, Register &Reg);
+  bool applyCombineAnyExtTrunc(MachineInstr &MI, Register &Reg);
+
+  /// Transform [asz]ext([asz]ext(x)) to [asz]ext x.
+  bool matchCombineExtOfExt(MachineInstr &MI,
+                            std::tuple<Register, unsigned> &MatchInfo);
+  bool applyCombineExtOfExt(MachineInstr &MI,
+                            std::tuple<Register, unsigned> &MatchInfo);
+
+  /// Transform fneg(fneg(x)) to x.
+  bool matchCombineFNegOfFNeg(MachineInstr &MI, Register &Reg);
+
+  /// Match fabs(fabs(x)) to fabs(x).
+  bool matchCombineFAbsOfFAbs(MachineInstr &MI, Register &Src);
+  bool applyCombineFAbsOfFAbs(MachineInstr &MI, Register &Src);
+
+  /// Transform trunc ([asz]ext x) to x or ([asz]ext x) or (trunc x).
+  bool matchCombineTruncOfExt(MachineInstr &MI,
+                              std::pair<Register, unsigned> &MatchInfo);
+  bool applyCombineTruncOfExt(MachineInstr &MI,
+                              std::pair<Register, unsigned> &MatchInfo);
+
+  /// Transform trunc (shl x, K) to shl (trunc x),
+  /// K => K < VT.getScalarSizeInBits().
+  bool matchCombineTruncOfShl(MachineInstr &MI,
+                              std::pair<Register, Register> &MatchInfo);
+  bool applyCombineTruncOfShl(MachineInstr &MI,
+                              std::pair<Register, Register> &MatchInfo);
+
+  /// Transform G_MUL(x, -1) to G_SUB(0, x)
+  bool applyCombineMulByNegativeOne(MachineInstr &MI);
+
+  /// Return true if any explicit use operand on \p MI is defined by a
+  /// G_IMPLICIT_DEF.
+  bool matchAnyExplicitUseIsUndef(MachineInstr &MI);
+
+  /// Return true if all register explicit use operands on \p MI are defined by
+  /// a G_IMPLICIT_DEF.
+  bool matchAllExplicitUsesAreUndef(MachineInstr &MI);
+
+  /// Return true if a G_SHUFFLE_VECTOR instruction \p MI has an undef mask.
+  bool matchUndefShuffleVectorMask(MachineInstr &MI);
+
+  /// Return true if a G_STORE instruction \p MI is storing an undef value.
+  bool matchUndefStore(MachineInstr &MI);
+
+  /// Return true if a G_SELECT instruction \p MI has an undef comparison.
+  bool matchUndefSelectCmp(MachineInstr &MI);
+
+  /// Return true if a G_SELECT instruction \p MI has a constant comparison. If
+  /// true, \p OpIdx will store the operand index of the known selected value.
+  bool matchConstantSelectCmp(MachineInstr &MI, unsigned &OpIdx);
+
+  /// Replace an instruction with a G_FCONSTANT with value \p C.
+  bool replaceInstWithFConstant(MachineInstr &MI, double C);
+
+  /// Replace an instruction with a G_CONSTANT with value \p C.
+  bool replaceInstWithConstant(MachineInstr &MI, int64_t C);
+
+  /// Replace an instruction with a G_IMPLICIT_DEF.
+  bool replaceInstWithUndef(MachineInstr &MI);
+
+  /// Delete \p MI and replace all of its uses with its \p OpIdx-th operand.
+  bool replaceSingleDefInstWithOperand(MachineInstr &MI, unsigned OpIdx);
+
+  /// Delete \p MI and replace all of its uses with \p Replacement.
+  bool replaceSingleDefInstWithReg(MachineInstr &MI, Register Replacement);
+
+  /// Return true if \p MOP1 and \p MOP2 are register operands are defined by
+  /// equivalent instructions.
+  bool matchEqualDefs(const MachineOperand &MOP1, const MachineOperand &MOP2);
+
+  /// Return true if \p MOP is defined by a G_CONSTANT with a value equal to
+  /// \p C.
+  bool matchConstantOp(const MachineOperand &MOP, int64_t C);
+
+  /// Optimize (cond ? x : x) -> x
+  bool matchSelectSameVal(MachineInstr &MI);
+
+  /// Optimize (x op x) -> x
+  bool matchBinOpSameVal(MachineInstr &MI);
+
+  /// Check if operand \p OpIdx is zero.
+  bool matchOperandIsZero(MachineInstr &MI, unsigned OpIdx);
+
+  /// Check if operand \p OpIdx is undef.
+  bool matchOperandIsUndef(MachineInstr &MI, unsigned OpIdx);
+
+  /// Check if operand \p OpIdx is known to be a power of 2.
+  bool matchOperandIsKnownToBeAPowerOfTwo(MachineInstr &MI, unsigned OpIdx);
+
+  /// Erase \p MI
+  bool eraseInst(MachineInstr &MI);
+
+  /// Return true if MI is a G_ADD which can be simplified to a G_SUB.
+  bool matchSimplifyAddToSub(MachineInstr &MI,
+                             std::tuple<Register, Register> &MatchInfo);
+  bool applySimplifyAddToSub(MachineInstr &MI,
+                             std::tuple<Register, Register> &MatchInfo);
+
+  /// Match (logic_op (op x...), (op y...)) -> (op (logic_op x, y))
+  bool
+  matchHoistLogicOpWithSameOpcodeHands(MachineInstr &MI,
+                                       InstructionStepsMatchInfo &MatchInfo);
+
+  /// Replace \p MI with a series of instructions described in \p MatchInfo.
+  bool applyBuildInstructionSteps(MachineInstr &MI,
+                                  InstructionStepsMatchInfo &MatchInfo);
+
+  /// Match ashr (shl x, C), C -> sext_inreg (C)
+  bool matchAshrShlToSextInreg(MachineInstr &MI,
+                               std::tuple<Register, int64_t> &MatchInfo);
+  bool applyAshShlToSextInreg(MachineInstr &MI,
+                              std::tuple<Register, int64_t> &MatchInfo);
+  /// \return true if \p MI is a G_AND instruction whose operands are x and y
+  /// where x & y == x or x & y == y. (E.g., one of operands is all-ones value.)
+  ///
+  /// \param [in] MI - The G_AND instruction.
+  /// \param [out] Replacement - A register the G_AND should be replaced with on
+  /// success.
+  bool matchRedundantAnd(MachineInstr &MI, Register &Replacement);
+
+  /// \return true if \p MI is a G_OR instruction whose operands are x and y
+  /// where x | y == x or x | y == y. (E.g., one of operands is all-zeros
+  /// value.)
+  ///
+  /// \param [in] MI - The G_OR instruction.
+  /// \param [out] Replacement - A register the G_OR should be replaced with on
+  /// success.
+  bool matchRedundantOr(MachineInstr &MI, Register &Replacement);
+
+  /// \return true if \p MI is a G_SEXT_INREG that can be erased.
+  bool matchRedundantSExtInReg(MachineInstr &MI);
+
+  /// Combine inverting a result of a compare into the opposite cond code.
+  bool matchNotCmp(MachineInstr &MI, SmallVectorImpl<Register> &RegsToNegate);
+  bool applyNotCmp(MachineInstr &MI, SmallVectorImpl<Register> &RegsToNegate);
+
+  /// Fold (xor (and x, y), y) -> (and (not x), y)
+  ///{
+  bool matchXorOfAndWithSameReg(MachineInstr &MI,
+                                std::pair<Register, Register> &MatchInfo);
+  bool applyXorOfAndWithSameReg(MachineInstr &MI,
+                                std::pair<Register, Register> &MatchInfo);
+  ///}
+
+  /// Combine G_PTR_ADD with nullptr to G_INTTOPTR
+  bool matchPtrAddZero(MachineInstr &MI);
+  bool applyPtrAddZero(MachineInstr &MI);
+
+  /// Combine G_UREM x, (known power of 2) to an add and bitmasking.
+  bool applySimplifyURemByPow2(MachineInstr &MI);
+
+  bool matchCombineInsertVecElts(MachineInstr &MI,
+                                 SmallVectorImpl<Register> &MatchInfo);
+
+  bool applyCombineInsertVecElts(MachineInstr &MI,
+                             SmallVectorImpl<Register> &MatchInfo);
 
   /// Try to transform \p MI by using all of the above
   /// combine functions. Returns true if changed.
   bool tryCombine(MachineInstr &MI);
+
+private:
+  // Memcpy family optimization helpers.
+  bool optimizeMemcpy(MachineInstr &MI, Register Dst, Register Src,
+                      unsigned KnownLen, Align DstAlign, Align SrcAlign,
+                      bool IsVolatile);
+  bool optimizeMemmove(MachineInstr &MI, Register Dst, Register Src,
+                       unsigned KnownLen, Align DstAlign, Align SrcAlign,
+                       bool IsVolatile);
+  bool optimizeMemset(MachineInstr &MI, Register Dst, Register Val,
+                      unsigned KnownLen, Align DstAlign, bool IsVolatile);
+
+  /// Given a non-indexed load or store instruction \p MI, find an offset that
+  /// can be usefully and legally folded into it as a post-indexing operation.
+  ///
+  /// \returns true if a candidate is found.
+  bool findPostIndexCandidate(MachineInstr &MI, Register &Addr, Register &Base,
+                              Register &Offset);
+
+  /// Given a non-indexed load or store instruction \p MI, find an offset that
+  /// can be usefully and legally folded into it as a pre-indexing operation.
+  ///
+  /// \returns true if a candidate is found.
+  bool findPreIndexCandidate(MachineInstr &MI, Register &Addr, Register &Base,
+                             Register &Offset);
 };
 } // namespace llvm