[RISCV] Use TableGen-based macro fusion (llvm#72224)

We convert existed macro fusions to TableGen.

Bacause `Fusion` depend on `Instruction` definitions which is defined
below `RISCVFeatures.td`, so we recommend user to add fusion features
when defining new processor.

(cherry picked from commit 3fdb431)

Author: wangpc-pp

llvm/lib/Target/RISCV/CMakeLists.txt

@@ -5,6 +5,7 @@ set(LLVM_TARGET_DEFINITIONS RISCV.td)
 tablegen(LLVM RISCVGenAsmMatcher.inc -gen-asm-matcher)
 tablegen(LLVM RISCVGenAsmWriter.inc -gen-asm-writer)
 tablegen(LLVM RISCVGenCompressInstEmitter.inc -gen-compress-inst-emitter)
+tablegen(LLVM RISCVGenMacroFusion.inc -gen-macro-fusion-pred)
 tablegen(LLVM RISCVGenDAGISel.inc -gen-dag-isel)
 tablegen(LLVM RISCVGenDisassemblerTables.inc -gen-disassembler)
 tablegen(LLVM RISCVGenInstrInfo.inc -gen-instr-info)
@@ -43,7 +44,6 @@ add_llvm_target(RISCVCodeGen
   RISCVISelDAGToDAG.cpp
   RISCVISelLowering.cpp
   RISCVMachineFunctionInfo.cpp
-  RISCVMacroFusion.cpp
   RISCVMergeBaseOffset.cpp
   RISCVOptWInstrs.cpp
   RISCVPostRAExpandPseudoInsts.cpp

llvm/lib/Target/RISCV/RISCV.td

@@ -30,6 +30,12 @@ include "RISCVCallingConv.td"
 include "RISCVInstrInfo.td"
 include "GISel/RISCVRegisterBanks.td"
 
+//===----------------------------------------------------------------------===//
+// RISC-V macro fusions.
+//===----------------------------------------------------------------------===//
+
+include "RISCVMacroFusion.td"
+
 //===----------------------------------------------------------------------===//
 // RISC-V Scheduling Models
 //===----------------------------------------------------------------------===//

llvm/lib/Target/RISCV/RISCVFeatures.td

@@ -1044,30 +1044,6 @@ def TuneDLenFactor2
    : SubtargetFeature<"dlen-factor-2", "DLenFactor2", "true",
                       "Vector unit DLEN(data path width) is half of VLEN">;
 
-def TuneLUIADDIFusion
-    : SubtargetFeature<"lui-addi-fusion", "HasLUIADDIFusion",
-                       "true", "Enable LUI+ADDI macrofusion">;
-
-def TuneAUIPCADDIFusion
-    : SubtargetFeature<"auipc-addi-fusion", "HasAUIPCADDIFusion",
-                       "true", "Enable AUIPC+ADDI macrofusion">;
-
-def TuneZExtHFusion
-    : SubtargetFeature<"zexth-fusion", "HasZExtHFusion",
-                       "true", "Enable SLLI+SRLI to be fused to zero extension of halfword">;
-
-def TuneZExtWFusion
-    : SubtargetFeature<"zextw-fusion", "HasZExtWFusion",
-                       "true", "Enable SLLI+SRLI to be fused to zero extension of word">;
-
-def TuneShiftedZExtWFusion
-    : SubtargetFeature<"shifted-zextw-fusion", "HasShiftedZExtWFusion",
-                       "true", "Enable SLLI+SRLI to be fused when computing (shifted) zero extension of word">;
-
-def TuneLDADDFusion
-    : SubtargetFeature<"ld-add-fusion", "HasLDADDFusion",
-                       "true", "Enable LD+ADD macrofusion.">;
-
 def TuneNoDefaultUnroll
     : SubtargetFeature<"no-default-unroll", "EnableDefaultUnroll", "false",
                        "Disable default unroll preference.">;

llvm/lib/Target/RISCV/RISCVMacroFusion.cpp

@@ -0,0 +1,93 @@
+//==----- RISCVMacroFusion.td - Macro Fusion Definitions -----*- tablegen -*-=//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// ===---------------------------------------------------------------------===//
+// The following definitions describe the macro fusion predicators.
+
+// Fuse LUI followed by ADDI or ADDIW:
+//   rd = imm[31:0] which decomposes to
+//   lui rd, imm[31:12]
+//   addi(w) rd, rd, imm[11:0]
+def TuneLUIADDIFusion
+  : SimpleFusion<"lui-addi-fusion", "HasLUIADDIFusion",
+                 "Enable LUI+ADDI macro fusion",
+                 CheckOpcode<[LUI]>,
+                 CheckOpcode<[ADDI, ADDIW]>>;
+
+// Fuse AUIPC followed by ADDI:
+//   auipc rd, imm20
+//   addi rd, rd, imm12
+def TuneAUIPCADDIFusion
+  : SimpleFusion<"auipc-addi-fusion", "HasAUIPCADDIFusion",
+                 "Enable AUIPC+ADDI macrofusion",
+                 CheckOpcode<[AUIPC]>,
+                 CheckOpcode<[ADDI]>>;
+
+// Fuse zero extension of halfword:
+//   slli rd, rs1, 48
+//   srli rd, rd, 48
+def TuneZExtHFusion
+  : SimpleFusion<"zexth-fusion", "HasZExtHFusion",
+                 "Enable SLLI+SRLI to be fused to zero extension of halfword",
+                 CheckAll<[
+                   CheckOpcode<[SLLI]>,
+                   CheckIsImmOperand<2>,
+                   CheckImmOperand<2, 48>
+                 ]>,
+                 CheckAll<[
+                   CheckOpcode<[SRLI]>,
+                   CheckIsImmOperand<2>,
+                   CheckImmOperand<2, 48>
+                 ]>>;
+
+// Fuse zero extension of word:
+//   slli rd, rs1, 32
+//   srli rd, rd, 32
+def TuneZExtWFusion
+  : SimpleFusion<"zextw-fusion", "HasZExtWFusion",
+                 "Enable SLLI+SRLI to be fused to zero extension of word",
+                 CheckAll<[
+                   CheckOpcode<[SLLI]>,
+                   CheckIsImmOperand<2>,
+                   CheckImmOperand<2, 32>
+                 ]>,
+                 CheckAll<[
+                   CheckOpcode<[SRLI]>,
+                   CheckIsImmOperand<2>,
+                   CheckImmOperand<2, 32>
+                 ]>>;
+
+// Fuse shifted zero extension of word:
+//   slli rd, rs1, 32
+//   srli rd, rd, x
+//   where 0 <= x < 32
+def TuneShiftedZExtWFusion
+  : SimpleFusion<"shifted-zextw-fusion", "HasShiftedZExtWFusion",
+                 "Enable SLLI+SRLI to be fused when computing (shifted) word zero extension",
+                 CheckAll<[
+                   CheckOpcode<[SLLI]>,
+                   CheckIsImmOperand<2>,
+                   CheckImmOperand<2, 32>
+                 ]>,
+                 CheckAll<[
+                   CheckOpcode<[SRLI]>,
+                   CheckIsImmOperand<2>,
+                   CheckImmOperandRange<2, 0, 31>
+                 ]>>;
+
+// Fuse load with add:
+//   add rd, rs1, rs2
+//   ld rd, 0(rd)
+def TuneLDADDFusion
+  : SimpleFusion<"ld-add-fusion", "HasLDADDFusion", "Enable LD+ADD macrofusion",
+                 CheckOpcode<[ADD]>,
+                 CheckAll<[
+                   CheckOpcode<[LD]>,
+                   CheckIsImmOperand<2>,
+                   CheckImmOperand<2, 0>
+                 ]>>;