1 files changed, 18 insertions, 37 deletions
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
index 759fdabbf2b..46ace199ba0 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -14,7 +14,6 @@
 #include "RISCV.h"
 #include "RISCVSubtarget.h"
 #include "RISCVTargetMachine.h"
-#include "Utils/RISCVMatInt.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
@@ -157,42 +156,24 @@ void RISCVInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
   BuildMI(MBB, I, DL, get(Opcode), DstReg).addFrameIndex(FI).addImm(0);
 }
 
-void RISCVInstrInfo::movImm(MachineBasicBlock &MBB,
-                            MachineBasicBlock::iterator MBBI,
-                            const DebugLoc &DL, Register DstReg, uint64_t Val,
-                            MachineInstr::MIFlag Flag) const {
-  MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
-  bool IsRV64 = MF->getSubtarget<RISCVSubtarget>().is64Bit();
-  Register SrcReg = RISCV::X0;
-  Register Result = MRI.createVirtualRegister(&RISCV::GPRRegClass);
-  unsigned Num = 0;
-
-  if (!IsRV64 && !isInt<32>(Val))
-    report_fatal_error("Should only materialize 32-bit constants for RV32");
-
-  RISCVMatInt::InstSeq Seq;
-  RISCVMatInt::generateInstSeq(Val, IsRV64, Seq);
-  assert(Seq.size() > 0);
-
-  for (RISCVMatInt::Inst &Inst : Seq) {
-    // Write the final result to DstReg if it's the last instruction in the Seq.
-    // Otherwise, write the result to the temp register.
-    if (++Num == Seq.size())
-      Result = DstReg;
-
-    if (Inst.Opc == RISCV::LUI) {
-      BuildMI(MBB, MBBI, DL, get(RISCV::LUI), Result)
-          .addImm(Inst.Imm)
-          .setMIFlag(Flag);
-    } else {
-      BuildMI(MBB, MBBI, DL, get(Inst.Opc), Result)
-          .addReg(SrcReg, RegState::Kill)
-          .addImm(Inst.Imm)
-          .setMIFlag(Flag);
-    }
-    // Only the first instruction has X0 as its source.
-    SrcReg = Result;
-  }
+void RISCVInstrInfo::movImm32(MachineBasicBlock &MBB,
+                              MachineBasicBlock::iterator MBBI,
+                              const DebugLoc &DL, Register DstReg, uint64_t Val,
+                              MachineInstr::MIFlag Flag) const {
+  assert(isInt<32>(Val) && "Can only materialize 32-bit constants");
+
+  // TODO: If the value can be materialized using only one instruction, only
+  // insert a single instruction.
+
+  uint64_t Hi20 = ((Val + 0x800) >> 12) & 0xfffff;
+  uint64_t Lo12 = SignExtend64<12>(Val);
+  BuildMI(MBB, MBBI, DL, get(RISCV::LUI), DstReg)
+      .addImm(Hi20)
+      .setMIFlag(Flag);
+  BuildMI(MBB, MBBI, DL, get(RISCV::ADDI), DstReg)
+      .addReg(DstReg, RegState::Kill)
+      .addImm(Lo12)
+      .setMIFlag(Flag);
 }
 
 // The contents of values added to Cond are not examined outside of