xref: /freebsd/contrib/llvm-project/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.h (revision 963f5dc7a30624e95d72fb7f87b8892651164e46)
1 //===- RISCVMatInt.h - Immediate materialisation ---------------*- 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 
9 #ifndef LLVM_LIB_TARGET_RISCV_MATINT_H
10 #define LLVM_LIB_TARGET_RISCV_MATINT_H
11 
12 #include "llvm/ADT/SmallVector.h"
13 #include "llvm/MC/SubtargetFeature.h"
14 #include <cstdint>
15 
16 namespace llvm {
17 class APInt;
18 class MCSubtargetInfo;
19 
20 namespace RISCVMatInt {
21 struct Inst {
22   unsigned Opc;
23   int64_t Imm;
24 
25   Inst(unsigned Opc, int64_t Imm) : Opc(Opc), Imm(Imm) {}
26 };
27 using InstSeq = SmallVector<Inst, 8>;
28 
29 // Helper to generate an instruction sequence that will materialise the given
30 // immediate value into a register. A sequence of instructions represented by a
31 // simple struct is produced rather than directly emitting the instructions in
32 // order to allow this helper to be used from both the MC layer and during
33 // instruction selection.
34 InstSeq generateInstSeq(int64_t Val, const FeatureBitset &ActiveFeatures);
35 
36 // Helper to estimate the number of instructions required to materialise the
37 // given immediate value into a register. This estimate does not account for
38 // `Val` possibly fitting into an immediate, and so may over-estimate.
39 //
40 // This will attempt to produce instructions to materialise `Val` as an
41 // `Size`-bit immediate.
42 //
43 // If CompressionCost is true it will use a different cost calculation if RVC is
44 // enabled. This should be used to compare two different sequences to determine
45 // which is more compressible.
46 int getIntMatCost(const APInt &Val, unsigned Size,
47                   const FeatureBitset &ActiveFeatures,
48                   bool CompressionCost = false);
49 } // namespace RISCVMatInt
50 } // namespace llvm
51 #endif
52