[libc-commits] [libc] [RISCV][GlobalISel] Select G_PTR_ADD (PR #67605)

Nitin John Raj via libc-commits libc-commits at lists.llvm.org
Tue Oct 10 11:15:56 PDT 2023


https://github.com/nitinjohnraj updated https://github.com/llvm/llvm-project/pull/67605

>From eef2a293d346c05d7fceaa241c0f8489c37e6dea Mon Sep 17 00:00:00 2001
From: Nitin John Raj <nitin.raj at sifive.com>
Date: Thu, 21 Sep 2023 10:41:50 -0700
Subject: [PATCH 1/3] [RISCV][GlobalISel] Select G_PTR_ADD

---
 .../RISCV/GISel/RISCVInstructionSelector.cpp  | 48 +++++++++++++++++-
 .../instruction-select/ptradd-rv32.mir        | 50 +++++++++++++++++++
 .../instruction-select/ptradd-rv64.mir        | 50 +++++++++++++++++++
 3 files changed, 147 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/ptradd-rv32.mir
 create mode 100644 llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/ptradd-rv64.mir

diff --git a/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp b/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
index 4f97a0d84f686f9..cead3a4a6c7fb06 100644
--- a/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
+++ b/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
@@ -45,6 +45,16 @@ class RISCVInstructionSelector : public InstructionSelector {
   getRegClassForTypeOnBank(LLT Ty, const RegisterBank &RB) const;
 
   bool selectImpl(MachineInstr &I, CodeGenCoverage &CoverageInfo) const;
+
+  // A lowering phase that runs before any selection attempts.
+  // Returns true if the instruction was modified.
+  bool preISelLower(MachineInstr &MI, MachineIRBuilder &MIB,
+                    MachineRegisterInfo &MRI);
+
+  bool replacePtrWithInt(MachineOperand &Op, MachineIRBuilder &MIB,
+                         MachineRegisterInfo &MRI);
+
+  // Custom selection methods
   bool selectCopy(MachineInstr &MI, MachineRegisterInfo &MRI) const;
   bool selectConstant(MachineInstr &MI, MachineIRBuilder &MIB,
                       MachineRegisterInfo &MRI) const;
@@ -130,12 +140,14 @@ bool RISCVInstructionSelector::earlySelectShift(
 }
 
 bool RISCVInstructionSelector::select(MachineInstr &MI) {
-  unsigned Opc = MI.getOpcode();
   MachineBasicBlock &MBB = *MI.getParent();
   MachineFunction &MF = *MBB.getParent();
   MachineRegisterInfo &MRI = MF.getRegInfo();
   MachineIRBuilder MIB(MI);
 
+  preISelLower(MI, MIB, MRI);
+  const unsigned Opc = MI.getOpcode();
+
   if (!isPreISelGenericOpcode(Opc) || Opc == TargetOpcode::G_PHI) {
     if (Opc == TargetOpcode::PHI || Opc == TargetOpcode::G_PHI) {
       const Register DefReg = MI.getOperand(0).getReg();
@@ -225,6 +237,7 @@ bool RISCVInstructionSelector::select(MachineInstr &MI) {
 
   switch (Opc) {
   case TargetOpcode::G_ANYEXT:
+  case TargetOpcode::G_PTRTOINT:
   case TargetOpcode::G_TRUNC:
     return selectCopy(MI, MRI);
   case TargetOpcode::G_CONSTANT:
@@ -244,6 +257,39 @@ bool RISCVInstructionSelector::select(MachineInstr &MI) {
   }
 }
 
+bool RISCVInstructionSelector::replacePtrWithInt(MachineOperand &Op,
+                                                 MachineIRBuilder &MIB,
+                                                 MachineRegisterInfo &MRI) {
+  assert(Op.isReg() && "Operand is not a register!");
+  Register PtrReg = Op.getReg();
+  assert(MRI.getType(PtrReg).isPointer() && "Operand is not a pointer!");
+
+  const LLT XLenLLT = LLT::scalar(STI.getXLen());
+  auto PtrToInt = MIB.buildPtrToInt(XLenLLT, PtrReg);
+  MRI.setRegBank(PtrToInt.getReg(0), RBI.getRegBank(RISCV::GPRRegBankID));
+  MRI.setType(PtrReg, XLenLLT);
+  Op.setReg(PtrToInt.getReg(0));
+  return select(*PtrToInt);
+}
+
+bool RISCVInstructionSelector::preISelLower(MachineInstr &MI,
+                                            MachineIRBuilder &MIB,
+                                            MachineRegisterInfo &MRI) {
+  switch (MI.getOpcode()) {
+  case TargetOpcode::G_PTR_ADD: {
+    Register DstReg = MI.getOperand(0).getReg();
+    const LLT XLenLLT = LLT::scalar(STI.getXLen());
+
+    replacePtrWithInt(MI.getOperand(1), MIB, MRI);
+    MI.setDesc(TII.get(TargetOpcode::G_ADD));
+    MRI.setType(DstReg, XLenLLT);
+    return true;
+  }
+  default:
+    return false;
+  }
+}
+
 void RISCVInstructionSelector::renderNegImm(MachineInstrBuilder &MIB,
                                             const MachineInstr &MI,
                                             int OpIdx) const {
diff --git a/llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/ptradd-rv32.mir b/llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/ptradd-rv32.mir
new file mode 100644
index 000000000000000..bc0395685b40e9e
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/ptradd-rv32.mir
@@ -0,0 +1,50 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=riscv32 -run-pass=instruction-select -simplify-mir \
+# RUN: -verify-machineinstrs %s -o - | FileCheck %s
+---
+name:            add_i32
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: add_i32
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:gpr = COPY $x11
+    ; CHECK-NEXT: [[ADD:%[0-9]+]]:gpr = ADD [[COPY]], [[COPY1]]
+    ; CHECK-NEXT: $x10 = COPY [[ADD]]
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:gprb(p0) = COPY $x10
+    %1:gprb(s32) = COPY $x11
+    %2:gprb(p0) = G_PTR_ADD %0, %1
+    $x10 = COPY %2(p0)
+    PseudoRET implicit $x10
+
+...
+---
+name:            addi_i32
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: addi_i32
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr = COPY $x10
+    ; CHECK-NEXT: [[ADDI:%[0-9]+]]:gpr = ADDI [[COPY]], 20
+    ; CHECK-NEXT: $x10 = COPY [[ADDI]]
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:gprb(p0) = COPY $x10
+    %1:gprb(s32) = G_CONSTANT i32 20
+    %2:gprb(p0) = G_PTR_ADD %0, %1
+    $x10 = COPY %2(p0)
+    PseudoRET implicit $x10
+
+...
diff --git a/llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/ptradd-rv64.mir b/llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/ptradd-rv64.mir
new file mode 100644
index 000000000000000..d024a7c659878de
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/ptradd-rv64.mir
@@ -0,0 +1,50 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=riscv64 -run-pass=instruction-select -simplify-mir \
+# RUN: -verify-machineinstrs %s -o - | FileCheck %s
+---
+name:            add_i64
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: add_i64
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:gpr = COPY $x11
+    ; CHECK-NEXT: [[ADD:%[0-9]+]]:gpr = ADD [[COPY]], [[COPY1]]
+    ; CHECK-NEXT: $x10 = COPY [[ADD]]
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:gprb(p0) = COPY $x10
+    %1:gprb(s64) = COPY $x11
+    %2:gprb(p0) = G_PTR_ADD %0, %1
+    $x10 = COPY %2(p0)
+    PseudoRET implicit $x10
+
+...
+---
+name:            addi_i64
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: addi_i64
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr = COPY $x10
+    ; CHECK-NEXT: [[ADDI:%[0-9]+]]:gpr = ADDI [[COPY]], 20
+    ; CHECK-NEXT: $x10 = COPY [[ADDI]]
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:gprb(p0) = COPY $x10
+    %1:gprb(s64) = G_CONSTANT i64 20
+    %2:gprb(p0) = G_PTR_ADD %0, %1
+    $x10 = COPY %2(p0)
+    PseudoRET implicit $x10
+
+...

>From 28f982ce78c092a02d63e7877f11c301a0e9fe78 Mon Sep 17 00:00:00 2001
From: Nitin John Raj <nitin.raj at sifive.com>
Date: Wed, 4 Oct 2023 17:19:22 -0700
Subject: [PATCH 2/3] bool preISelLower -> void preISelLower

---
 llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp b/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
index cead3a4a6c7fb06..7537d75c0aeba40 100644
--- a/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
+++ b/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
@@ -48,7 +48,7 @@ class RISCVInstructionSelector : public InstructionSelector {
 
   // A lowering phase that runs before any selection attempts.
   // Returns true if the instruction was modified.
-  bool preISelLower(MachineInstr &MI, MachineIRBuilder &MIB,
+  void preISelLower(MachineInstr &MI, MachineIRBuilder &MIB,
                     MachineRegisterInfo &MRI);
 
   bool replacePtrWithInt(MachineOperand &Op, MachineIRBuilder &MIB,
@@ -260,7 +260,6 @@ bool RISCVInstructionSelector::select(MachineInstr &MI) {
 bool RISCVInstructionSelector::replacePtrWithInt(MachineOperand &Op,
                                                  MachineIRBuilder &MIB,
                                                  MachineRegisterInfo &MRI) {
-  assert(Op.isReg() && "Operand is not a register!");
   Register PtrReg = Op.getReg();
   assert(MRI.getType(PtrReg).isPointer() && "Operand is not a pointer!");
 
@@ -272,7 +271,7 @@ bool RISCVInstructionSelector::replacePtrWithInt(MachineOperand &Op,
   return select(*PtrToInt);
 }
 
-bool RISCVInstructionSelector::preISelLower(MachineInstr &MI,
+void RISCVInstructionSelector::preISelLower(MachineInstr &MI,
                                             MachineIRBuilder &MIB,
                                             MachineRegisterInfo &MRI) {
   switch (MI.getOpcode()) {
@@ -283,10 +282,7 @@ bool RISCVInstructionSelector::preISelLower(MachineInstr &MI,
     replacePtrWithInt(MI.getOperand(1), MIB, MRI);
     MI.setDesc(TII.get(TargetOpcode::G_ADD));
     MRI.setType(DstReg, XLenLLT);
-    return true;
   }
-  default:
-    return false;
   }
 }
 

>From 527fc0f84b01fda00e0ad96576b1bf33c879b889 Mon Sep 17 00:00:00 2001
From: Nitin John Raj <nitin.raj at sifive.com>
Date: Thu, 5 Oct 2023 16:48:02 -0700
Subject: [PATCH 3/3] Added missing break statement

---
 llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp b/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
index 7537d75c0aeba40..625e50ae90d0896 100644
--- a/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
+++ b/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
@@ -282,6 +282,7 @@ void RISCVInstructionSelector::preISelLower(MachineInstr &MI,
     replacePtrWithInt(MI.getOperand(1), MIB, MRI);
     MI.setDesc(TII.get(TargetOpcode::G_ADD));
     MRI.setType(DstReg, XLenLLT);
+    break;
   }
   }
 }



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