[RISCV] Implement isLegalICmpImmediate

I'm unable to construct a representative test case that demonstrates the 
advantage, but it seems sensible to report accurate target-specific 
information regardless.

llvm-svn: 330938

2 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 7c1d01845b4..16b4bddcd5c 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -183,6 +183,10 @@ bool RISCVTargetLowering::isLegalAddressingMode(const DataLayout &DL,
   return true;
 }
 
+bool RISCVTargetLowering::isLegalICmpImmediate(int64_t Imm) const {
+  return isInt<12>(Imm);
+}
+
 bool RISCVTargetLowering::isLegalAddImmediate(int64_t Imm) const {
   return isInt<12>(Imm);
 }
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.h b/llvm/lib/Target/RISCV/RISCVISelLowering.h
index 7e4a1347127..dccd0315bbf 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.h
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.h
@@ -42,6 +42,7 @@ public:
   bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM, Type *Ty,
                              unsigned AS,
                              Instruction *I = nullptr) const override;
+  bool isLegalICmpImmediate(int64_t Imm) const override;
   bool isLegalAddImmediate(int64_t Imm) const override;
 
   // Provide custom lowering hooks for some operations.