xref: /freebsd/contrib/llvm-project/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.h (revision e32fecd0c2c3ee37c47ee100f169e7eb0282a873)
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_MCTARGETDESC_MATINT_H
10 #define LLVM_LIB_TARGET_RISCV_MCTARGETDESC_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 
19 namespace RISCVMatInt {
20 
21 enum OpndKind {
22   RegImm, // ADDI/ADDIW/SLLI/SRLI/BSETI/BCLRI
23   Imm,    // LUI
24   RegReg, // SH1ADD/SH2ADD/SH3ADD
25   RegX0,  // ADD_UW
26 };
27 
28 struct Inst {
29   unsigned Opc;
30   int64_t Imm;
31 
32   Inst(unsigned Opc, int64_t Imm) : Opc(Opc), Imm(Imm) {}
33 
34   OpndKind getOpndKind() const;
35 };
36 using InstSeq = SmallVector<Inst, 8>;
37 
38 // Helper to generate an instruction sequence that will materialise the given
39 // immediate value into a register. A sequence of instructions represented by a
40 // simple struct is produced rather than directly emitting the instructions in
41 // order to allow this helper to be used from both the MC layer and during
42 // instruction selection.
43 InstSeq generateInstSeq(int64_t Val, const FeatureBitset &ActiveFeatures);
44 
45 // Helper to estimate the number of instructions required to materialise the
46 // given immediate value into a register. This estimate does not account for
47 // `Val` possibly fitting into an immediate, and so may over-estimate.
48 //
49 // This will attempt to produce instructions to materialise `Val` as an
50 // `Size`-bit immediate.
51 //
52 // If CompressionCost is true it will use a different cost calculation if RVC is
53 // enabled. This should be used to compare two different sequences to determine
54 // which is more compressible.
55 int getIntMatCost(const APInt &Val, unsigned Size,
56                   const FeatureBitset &ActiveFeatures,
57                   bool CompressionCost = false);
58 } // namespace RISCVMatInt
59 } // namespace llvm
60 #endif
61