3 files changed, 11 insertions, 1 deletions
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.td b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
index 4e528d1fc8e..81dcc799171 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
@@ -267,7 +267,7 @@ class Priv<string opcodestr, bits<7> funct7>
 // Instructions
 //===----------------------------------------------------------------------===//
 
-let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in {
+let hasSideEffects = 0, isReMaterializable = 1, mayLoad = 0, mayStore = 0 in {
 def LUI : RVInstU<OPC_LUI, (outs GPR:$rd), (ins uimm20:$imm20),
                   "lui", "$rd, $imm20">;
 
@@ -301,7 +301,11 @@ def SB : Store_rri<0b000, "sb">;
 def SH : Store_rri<0b001, "sh">;
 def SW : Store_rri<0b010, "sw">;
 
+// ADDI isn't always rematerializable, but isReMaterializable will be used as
+// a hint which is verified in isReallyTriviallyReMaterializable.
+let isReMaterializable = 1 in
 def ADDI  : ALU_ri<0b000, "addi">;
+
 def SLTI  : ALU_ri<0b010, "slti">;
 def SLTIU : ALU_ri<0b011, "sltiu">;
 def XORI  : ALU_ri<0b100, "xori">;
diff --git a/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp b/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
index 6ad8bf7bca0..f72730fb1a0 100644
--- a/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
@@ -50,6 +50,10 @@ BitVector RISCVRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   return Reserved;
 }
 
+bool RISCVRegisterInfo::isConstantPhysReg(unsigned PhysReg) const {
+  return PhysReg == RISCV::X0;
+}
+
 const uint32_t *RISCVRegisterInfo::getNoPreservedMask() const {
   return CSR_NoRegs_RegMask;
 }
diff --git a/llvm/lib/Target/RISCV/RISCVRegisterInfo.h b/llvm/lib/Target/RISCV/RISCVRegisterInfo.h
index a81dea09401..cbbb70079dd 100644
--- a/llvm/lib/Target/RISCV/RISCVRegisterInfo.h
+++ b/llvm/lib/Target/RISCV/RISCVRegisterInfo.h
@@ -32,6 +32,8 @@ struct RISCVRegisterInfo : public RISCVGenRegisterInfo {
 
   BitVector getReservedRegs(const MachineFunction &MF) const override;
 
+  bool isConstantPhysReg(unsigned PhysReg) const override;
+
   const uint32_t *getNoPreservedMask() const override;
 
   void eliminateFrameIndex(MachineBasicBlock::iterator MI, int SPAdj,