1 //===- llvm/CodeGen/GlobalISel/CombinerInfo.h ------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 /// \file
9 /// Interface for Targets to specify which operations are combined how and when.
10 ///
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CODEGEN_GLOBALISEL_COMBINERINFO_H
14 #define LLVM_CODEGEN_GLOBALISEL_COMBINERINFO_H
15 
16 #include <cassert>
17 namespace llvm {
18 
19 class GISelChangeObserver;
20 class LegalizerInfo;
21 class MachineInstr;
22 class MachineIRBuilder;
23 
24 // Contains information relevant to enabling/disabling various combines for a
25 // pass.
26 class CombinerInfo {
27 public:
28   CombinerInfo(bool AllowIllegalOps, bool ShouldLegalizeIllegal,
29                const LegalizerInfo *LInfo, bool OptEnabled, bool OptSize,
30                bool MinSize)
31       : IllegalOpsAllowed(AllowIllegalOps),
32         LegalizeIllegalOps(ShouldLegalizeIllegal), LInfo(LInfo),
33         EnableOpt(OptEnabled), EnableOptSize(OptSize), EnableMinSize(MinSize) {
34     assert(((AllowIllegalOps || !LegalizeIllegalOps) || LInfo) &&
35            "Expecting legalizerInfo when illegalops not allowed");
36   }
37   virtual ~CombinerInfo() = default;
38   /// If \p IllegalOpsAllowed is false, the CombinerHelper will make use of
39   /// the legalizerInfo to check for legality before each transformation.
40   bool IllegalOpsAllowed; // TODO: Make use of this.
41 
42   /// If \p LegalizeIllegalOps is true, the Combiner will also legalize the
43   /// illegal ops that are created.
44   bool LegalizeIllegalOps; // TODO: Make use of this.
45   const LegalizerInfo *LInfo;
46 
47   /// Whether optimizations should be enabled. This is to distinguish between
48   /// uses of the combiner unconditionally and only when optimizations are
49   /// specifically enabled/
50   bool EnableOpt;
51   /// Whether we're optimizing for size.
52   bool EnableOptSize;
53   /// Whether we're optimizing for minsize (-Oz).
54   bool EnableMinSize;
55 
56   /// Attempt to combine instructions using MI as the root.
57   ///
58   /// Use Observer to report the creation, modification, and erasure of
59   /// instructions. GISelChangeObserver will automatically report certain
60   /// kinds of operations. These operations are:
61   /// * Instructions that are newly inserted into the MachineFunction
62   /// * Instructions that are erased from the MachineFunction.
63   ///
64   /// However, it is important to report instruction modification and this is
65   /// not automatic.
66   virtual bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
67                        MachineIRBuilder &B) const = 0;
68 };
69 } // namespace llvm
70 
71 #endif
72