return true;
}
+ /// Represents a predicate at the MachineFunction level. The control flow a
+ /// MachineBranchPredicate represents is:
+ ///
+ /// Reg <def>= LHS `Predicate` RHS == ConditionDef
+ /// if Reg then goto TrueDest else goto FalseDest
+ ///
+ struct MachineBranchPredicate {
+ enum ComparePredicate {
+ PRED_EQ, // True if two values are equal
+ PRED_NE, // True if two values are not equal
+ PRED_INVALID // Sentinel value
+ };
+
+ ComparePredicate Predicate;
+ MachineOperand LHS;
+ MachineOperand RHS;
+ MachineBasicBlock *TrueDest;
+ MachineBasicBlock *FalseDest;
+ MachineInstr *ConditionDef;
+
+ /// SingleUseCondition is true if ConditionDef is dead except for the
+ /// branch(es) at the end of the basic block.
+ ///
+ bool SingleUseCondition;
+
+ explicit MachineBranchPredicate()
+ : Predicate(PRED_INVALID), LHS(MachineOperand::CreateImm(0)),
+ RHS(MachineOperand::CreateImm(0)), TrueDest(nullptr),
+ FalseDest(nullptr), ConditionDef(nullptr), SingleUseCondition(false) {
+ }
+ };
+
+ /// Analyze the branching code at the end of MBB and parse it into the
+ /// MachineBranchPredicate structure if possible. Returns false on success
+ /// and true on failure.
+ ///
+ /// If AllowModify is true, then this routine is allowed to modify the basic
+ /// block (e.g. delete instructions after the unconditional branch).
+ ///
+ virtual bool AnalyzeBranchPredicate(MachineBasicBlock &MBB,
+ MachineBranchPredicate &MBP,
+ bool AllowModify = false) const {
+ return true;
+ }
+
/// Remove the branching code at the end of the specific MBB.
/// This is only invoked in cases where AnalyzeBranch returns success. It
/// returns the number of instructions that were removed.
/// order since the pattern evaluator stops checking as soon as it finds a
/// faster sequence.
/// \param Root - Instruction that could be combined with one of its operands
- /// \param Pattern - Vector of possible combination pattern
- virtual bool hasPattern(
+ /// \param Pattern - Vector of possible combination patterns
+ virtual bool getMachineCombinerPatterns(
MachineInstr &Root,
SmallVectorImpl<MachineCombinerPattern::MC_PATTERN> &Pattern) const {
return false;
}
- /// When hasPattern() finds a pattern this function generates the instructions
- /// that could replace the original code sequence. The client has to decide
- /// whether the actual replacement is beneficial or not.
+ /// When getMachineCombinerPatterns() finds patterns, this function generates
+ /// the instructions that could replace the original code sequence. The client
+ /// has to decide whether the actual replacement is beneficial or not.
/// \param Root - Instruction that could be combined with one of its operands
- /// \param P - Combination pattern for Root
+ /// \param Pattern - Combination pattern for Root
/// \param InsInstrs - Vector of new instructions that implement P
/// \param DelInstrs - Old instructions, including Root, that could be
/// replaced by InsInstr
/// \param InstrIdxForVirtReg - map of virtual register to instruction in
/// InsInstr that defines it
virtual void genAlternativeCodeSequence(
- MachineInstr &Root, MachineCombinerPattern::MC_PATTERN P,
+ MachineInstr &Root, MachineCombinerPattern::MC_PATTERN Pattern,
SmallVectorImpl<MachineInstr *> &InsInstrs,
SmallVectorImpl<MachineInstr *> &DelInstrs,
DenseMap<unsigned, unsigned> &InstrIdxForVirtReg) const {