[GlobalISel] Generate prelegalizer combiner rules

5 files changed, 250 insertions, 5 deletions

diff --git a/backend/lib/Target/RISCV/CMakeLists.txt b/backend/lib/Target/RISCV/CMakeLists.txt
index 3972a92..2e1e224 100644
--- a/backend/lib/Target/RISCV/CMakeLists.txt
+++ b/backend/lib/Target/RISCV/CMakeLists.txt
@@ -19,6 +19,7 @@ set(
   "${CMAKE_CURRENT_SOURCE_DIR}/RISCVGISelControlFlow.rccdesc"
   "${CMAKE_CURRENT_SOURCE_DIR}/RISCVGISelShift.rccdesc"
   "${CMAKE_CURRENT_SOURCE_DIR}/RISCVGISelFloating.rccdesc"
+  "${CMAKE_CURRENT_SOURCE_DIR}/RISCVGISelCombiner.rccdesc"
 )
 set(RCCBackendRISCVTableGenArguments)
 foreach(RCCBackendRISCVDescriptionSource IN LISTS RCCBackendRISCVDescriptionSources)
@@ -40,6 +41,10 @@ set(
   RCCBackendRISCVGeneratedGlobalISel
   "${RCC_BACKEND_BINARY_DIR}/generated/lib/Target/RISCV/RISCVGenGlobalISel.inc"
 )
+set(
+  RCCBackendRISCVGeneratedGlobalISelCombiner
+  "${RCC_BACKEND_BINARY_DIR}/generated/lib/Target/RISCV/RISCVGenGlobalISelCombiner.inc"
+)
 
 add_custom_command(
   OUTPUT
@@ -47,6 +52,7 @@ add_custom_command(
     "${RCCBackendRISCVGeneratedInstructionHeader}"
     "${RCCBackendRISCVGeneratedTables}"
     "${RCCBackendRISCVGeneratedGlobalISel}"
+    "${RCCBackendRISCVGeneratedGlobalISelCombiner}"
   COMMAND
     "$<TARGET_FILE:RCCBackendTableGenTool>"
     ${RCCBackendRISCVTableGenArguments}
@@ -54,6 +60,7 @@ add_custom_command(
     --instruction-header "${RCCBackendRISCVGeneratedInstructionHeader}"
     --tables "${RCCBackendRISCVGeneratedTables}"
     --global-isel "${RCCBackendRISCVGeneratedGlobalISel}"
+    --global-isel-combiner "${RCCBackendRISCVGeneratedGlobalISelCombiner}"
   DEPENDS RCCBackendTableGenTool ${RCCBackendRISCVDescriptionSources}
   COMMENT "Generating RCC RV64GC target tables"
   VERBATIM
@@ -66,6 +73,7 @@ add_custom_target(
     "${RCCBackendRISCVGeneratedInstructionHeader}"
     "${RCCBackendRISCVGeneratedTables}"
     "${RCCBackendRISCVGeneratedGlobalISel}"
+    "${RCCBackendRISCVGeneratedGlobalISelCombiner}"
 )
 
 set_source_files_properties(
@@ -73,6 +81,7 @@ set_source_files_properties(
   "${RCCBackendRISCVGeneratedInstructionHeader}"
   "${RCCBackendRISCVGeneratedTables}"
   "${RCCBackendRISCVGeneratedGlobalISel}"
+  "${RCCBackendRISCVGeneratedGlobalISelCombiner}"
   PROPERTIES GENERATED TRUE HEADER_FILE_ONLY TRUE
 )
 
@@ -80,6 +89,7 @@ add_library(
   RCCBackendRISCV
   GISel/RISCVCallLowering.cpp
   GISel/RISCVInstructionSelector.cpp
+  GISel/RISCVGISelCombiner.cpp
   GISel/RISCVLegalizerInfo.cpp
   GISel/RISCVRegisterBankInfo.cpp
   RISCVInstrInfo.cpp
@@ -106,6 +116,7 @@ add_library(
   "${RCCBackendRISCVGeneratedInstructionHeader}"
   "${RCCBackendRISCVGeneratedTables}"
   "${RCCBackendRISCVGeneratedGlobalISel}"
+  "${RCCBackendRISCVGeneratedGlobalISelCombiner}"
 )
 add_library(RCCBackend::RISCV ALIAS RCCBackendRISCV)
 add_dependencies(RCCBackendRISCV RCCBackendRISCVGeneratedTablesTarget)
@@ -155,6 +166,7 @@ rcc_backend_register_format_files(
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVCallLowering.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVCallLowering.h"
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVInstructionSelector.cpp"
+  "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVGISelCombiner.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVLegalizerInfo.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVLegalizerInfo.h"
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVRegisterBankInfo.cpp"
@@ -199,6 +211,7 @@ rcc_backend_register_format_files(
 rcc_backend_register_tidy_files(
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVCallLowering.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVInstructionSelector.cpp"
+  "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVGISelCombiner.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVLegalizerInfo.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/GISel/RISCVRegisterBankInfo.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/RISCVInstrInfo.cpp"
diff --git a/backend/lib/Target/RISCV/GISel/RISCVGISelCombiner.cpp b/backend/lib/Target/RISCV/GISel/RISCVGISelCombiner.cpp
new file mode 100644
index 0000000..bf67c0a
--- /dev/null
+++ b/backend/lib/Target/RISCV/GISel/RISCVGISelCombiner.cpp
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "RISCV.h"
+#include "rcc/CodeGen/GlobalISel/GIMatchTableExecutor.h"
+#include "rcc/CodeGen/MachineFunction.h"
+#include "rcc/CodeGen/MachineInstr.h"
+#include "rcc/CodeGen/MachineRegisterInfo.h"
+#include "rcc/CodeGen/TargetDescription.h"
+
+#include <string>
+
+namespace rcc::riscv {
+namespace {
+
+#define GET_GLOBALISEL_COMBINER_TABLE
+#include "RISCVGenGlobalISelCombiner.inc"
+#undef GET_GLOBALISEL_COMBINER_TABLE
+
+class RISCVGISelCombinerExecutor final : public GIMatchTableExecutor {
+protected:
+  [[nodiscard]] Expected<bool>
+  matchesTargetPredicate(std::string_view Name, const MachineInstr &Instruction,
+                         const MachineFunction &Function,
+                         const TargetDescription &Target) const override {
+    if (Name != "sext_cheaper_than_zext")
+      return GIMatchTableExecutor::matchesTargetPredicate(Name, Instruction, Function, Target);
+    const MachineOperand *Destination = Instruction.operandAt(0);
+    const MachineOperand *Source = Instruction.operandAt(1);
+    const Register *DestinationReg =
+        Destination == nullptr ? nullptr : Destination->getIf<Register>();
+    const Register *SourceReg = Source == nullptr ? nullptr : Source->getIf<Register>();
+    if (DestinationReg == nullptr || SourceReg == nullptr || !DestinationReg->isVirtual() ||
+        !SourceReg->isVirtual())
+      return false;
+    auto DestinationType = Function.registerInfo().getType(*DestinationReg);
+    auto SourceType = Function.registerInfo().getType(*SourceReg);
+    if (!DestinationType || !SourceType)
+      return false;
+    return DestinationType->isCategoryNeutralScalar() && SourceType->isCategoryNeutralScalar() &&
+           DestinationType->scalarBitWidth() == 64 && SourceType->scalarBitWidth() == 32;
+  }
+};
+
+} // namespace
+
+const GIMatchTable &giselCombinerTable() noexcept {
+  static constexpr GIMatchTable Table = generatedGlobalISelCombinerMatchTable();
+  return Table;
+}
+
+const GIMatchTableExecutor &giselCombinerExecutor() noexcept {
+  static const RISCVGISelCombinerExecutor Executor;
+  return Executor;
+}
+
+} // namespace rcc::riscv
diff --git a/backend/lib/Target/RISCV/RISCV.h b/backend/lib/Target/RISCV/RISCV.h
index 1a81f59..4699091 100644
--- a/backend/lib/Target/RISCV/RISCV.h
+++ b/backend/lib/Target/RISCV/RISCV.h
@@ -3,6 +3,7 @@
 #ifndef RCC_LIB_TARGET_RISCV_RISCV_H
 #define RCC_LIB_TARGET_RISCV_RISCV_H
 
+#include "rcc/CodeGen/GlobalISel/GIMatchTableExecutor.h"
 #include "rcc/CodeGen/MachineCombinerPattern.h"
 #include "rcc/CodeGen/MachineOptimizationPipeline.h"
 #include "rcc/CodeGen/TargetFrameLowering.h"
@@ -28,6 +29,8 @@ createRISCVInstructionSelector(const RISCVSubtarget &Subtarget,
 [[nodiscard]] const TargetFrameLowering &frameLowering() noexcept;
 [[nodiscard]] const TargetSchedulingModel &schedulingModel() noexcept;
 [[nodiscard]] const TargetMachineCombinerInfo &machineCombinerInfo() noexcept;
+[[nodiscard]] const GIMatchTable &giselCombinerTable() noexcept;
+[[nodiscard]] const GIMatchTableExecutor &giselCombinerExecutor() noexcept;
 [[nodiscard]] const TargetMemoryFoldingInfo &memoryFoldingInfo() noexcept;
 [[nodiscard]] const TargetPseudoExpansionInfo &pseudoExpansionInfo() noexcept;
 [[nodiscard]] MachineOptimizationPipelineTargetInfo optimizationPipelineInfo() noexcept;
diff --git a/backend/lib/Target/RISCV/RISCVGISelCombiner.rccdesc b/backend/lib/Target/RISCV/RISCVGISelCombiner.rccdesc
new file mode 100644
index 0000000..5f8585b
--- /dev/null
+++ b/backend/lib/Target/RISCV/RISCVGISelCombiner.rccdesc
@@ -0,0 +1,173 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+combiner_rules:
+  -
+    id: combine_nneg_zext
+    priority: 500
+    match:
+      opcode: G_ZEXT
+      result_type: { kind: scalar, bits: 64 }
+      operand_types:
+        - { index: 1, kind: scalar, bits: 32 }
+      target_predicates: [sext_cheaper_than_zext]
+      flags: [nneg]
+      def_use:
+        -
+          operand: 1
+          opcode: G_TRUNC
+          captures:
+            - { id: source, operand: 1 }
+            - { id: trunc_result, operand: 0 }
+    apply:
+      action: mutate_root
+      opcode: G_SEXT_INREG
+      operands:
+        - { operand: 0 }
+        - { captured_operand: source }
+        - { captured_type_bits: trunc_result }
+      clear_flags: [nneg]
+      erase_operand_definitions: [1]
+  -
+    id: combine_shl_zero
+    priority: 100
+    match:
+      opcode: G_SHL
+      def_use:
+        -
+          operand: 1
+          opcode: G_CONSTANT
+          captures:
+            - { id: zero, operand: 0 }
+          operand_def_constants:
+            - index: 1
+              ranges: [{ min: 0, max: 0 }]
+    apply:
+      action: replace_root_with_capture
+      capture: zero
+      erase_operand_definitions: [1]
+  -
+    id: combine_lshr_zero
+    priority: 100
+    match:
+      opcode: G_LSHR
+      def_use:
+        -
+          operand: 1
+          opcode: G_CONSTANT
+          captures:
+            - { id: zero, operand: 0 }
+          operand_def_constants:
+            - index: 1
+              ranges: [{ min: 0, max: 0 }]
+    apply:
+      action: replace_root_with_capture
+      capture: zero
+      erase_operand_definitions: [1]
+  -
+    id: combine_ashr_zero
+    priority: 100
+    match:
+      opcode: G_ASHR
+      def_use:
+        -
+          operand: 1
+          opcode: G_CONSTANT
+          captures:
+            - { id: zero, operand: 0 }
+          operand_def_constants:
+            - index: 1
+              ranges: [{ min: 0, max: 0 }]
+    apply:
+      action: replace_root_with_capture
+      capture: zero
+      erase_operand_definitions: [1]
+  -
+    id: combine_sdiv_zero
+    priority: 100
+    match:
+      opcode: G_SDIV
+      def_use:
+        -
+          operand: 1
+          opcode: G_CONSTANT
+          captures:
+            - { id: zero, operand: 0 }
+          operand_def_constants:
+            - index: 1
+              ranges: [{ min: 0, max: 0 }]
+    apply:
+      action: replace_root_with_capture
+      capture: zero
+      erase_operand_definitions: [1]
+  -
+    id: combine_udiv_zero
+    priority: 100
+    match:
+      opcode: G_UDIV
+      def_use:
+        -
+          operand: 1
+          opcode: G_CONSTANT
+          captures:
+            - { id: zero, operand: 0 }
+          operand_def_constants:
+            - index: 1
+              ranges: [{ min: 0, max: 0 }]
+    apply:
+      action: replace_root_with_capture
+      capture: zero
+      erase_operand_definitions: [1]
+  -
+    id: combine_srem_zero
+    priority: 100
+    match:
+      opcode: G_SREM
+      def_use:
+        -
+          operand: 1
+          opcode: G_CONSTANT
+          captures:
+            - { id: zero, operand: 0 }
+          operand_def_constants:
+            - index: 1
+              ranges: [{ min: 0, max: 0 }]
+    apply:
+      action: replace_root_with_capture
+      capture: zero
+      erase_operand_definitions: [1]
+  -
+    id: combine_urem_zero
+    priority: 100
+    match:
+      opcode: G_UREM
+      def_use:
+        -
+          operand: 1
+          opcode: G_CONSTANT
+          captures:
+            - { id: zero, operand: 0 }
+          operand_def_constants:
+            - index: 1
+              ranges: [{ min: 0, max: 0 }]
+    apply:
+      action: replace_root_with_capture
+      capture: zero
+      erase_operand_definitions: [1]
+  -
+    id: combine_mul_zero
+    priority: 100
+    match:
+      opcode: G_MUL
+      def_use:
+        -
+          operand: 1
+          opcode: G_CONSTANT
+          captures:
+            - { id: zero, operand: 0 }
+          operand_def_constants:
+            - index: 1
+              ranges: [{ min: 0, max: 0 }]
+    apply:
+      action: replace_root_with_capture
+      capture: zero
+      erase_operand_definitions: [1]
diff --git a/backend/lib/Target/RISCV/RISCVPipeline.cpp b/backend/lib/Target/RISCV/RISCVPipeline.cpp
index 00a4398..c24c57f 100644
--- a/backend/lib/Target/RISCV/RISCVPipeline.cpp
+++ b/backend/lib/Target/RISCV/RISCVPipeline.cpp
@@ -6,10 +6,10 @@
 #include "GISel/RISCVRegisterBankInfo.h"
 #include "RISCV.h"
 #include "RISCVInstrInfo.h"
+#include "rcc/CodeGen/GlobalISel/Combiner.h"
 #include "rcc/CodeGen/GlobalISel/InstructionSelect.h"
 #include "rcc/CodeGen/GlobalISel/Legalizer.h"
 #include "rcc/CodeGen/GlobalISel/RegBankSelect.h"
-#include "rcc/CodeGen/MachineCombiner.h"
 #include "rcc/CodeGen/MachineFunction.h"
 #include "rcc/CodeGen/MachineOptimizationPipeline.h"
 #include "rcc/CodeGen/MachinePseudoExpansion.h"
@@ -41,8 +41,8 @@ template <typename PassT, typename... ArgumentT>
 [[nodiscard]] Expected<void> addInitialPipeline(MachineFunctionPassManager &Pipeline,
                                                 const RISCVSubtarget &Subtarget,
                                                 RISCVPipelineOptions Options) {
-  auto Added = addPass<MachineCombinerPass>(Pipeline, machineCombinerInfo(),
-                                            MachineCombinerStage::PreLegalizer);
+  auto Added = addPass<GlobalISelCombinerPass>(
+      Pipeline, giselCombinerTable(), giselCombinerExecutor(), "riscv-prelegalizer-combiner");
   if (!Added)
     return std::unexpected(Added.error());
   Added = addPass<Legalizer>(Pipeline, Subtarget.getLegalizerInfo(), Options.Optimization,
@@ -99,8 +99,8 @@ Expected<void> addCanonicalPipeline(MachineFunctionPassManager &Pipeline,
                                     const MachineFunction &Function,
                                     const RISCVSubtarget &Subtarget, RISCVPipelineOptions Options) {
   if (!Function.properties().has(MachineFunctionProperty::Legalized)) {
-    auto Added = addPass<MachineCombinerPass>(Pipeline, machineCombinerInfo(),
-                                              MachineCombinerStage::PreLegalizer);
+    auto Added = addPass<GlobalISelCombinerPass>(
+        Pipeline, giselCombinerTable(), giselCombinerExecutor(), "riscv-prelegalizer-combiner");
     if (!Added)
       return std::unexpected(Added.error());
     Added = addPass<Legalizer>(Pipeline, Subtarget.getLegalizerInfo(), Options.Optimization,