Index: lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
===================================================================
--- lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -216,6 +216,18 @@
     return (isRV64() && isUInt<6>(Imm)) || isUInt<5>(Imm);
   }
 
+  bool isUImmLog2XLenNonZero() const {
+    int64_t Imm;
+    RISCVMCExpr::VariantKind VK;
+    if (!isImm())
+      return false;
+    if (!evaluateConstantImm(Imm, VK) || VK != RISCVMCExpr::VK_RISCV_None)
+      return false;
+    if (Imm == 0)
+      return false;
+    return (isRV64() && isUInt<6>(Imm)) || isUInt<5>(Imm);
+  }
+
   bool isUImm5() const {
     int64_t Imm;
     RISCVMCExpr::VariantKind VK;
@@ -592,10 +604,12 @@
     if (isRV64())
       return generateImmOutOfRangeError(Operands, ErrorInfo, 0, (1 << 6) - 1);
     return generateImmOutOfRangeError(Operands, ErrorInfo, 0, (1 << 5) - 1);
+  case Match_InvalidUImmLog2XLenNonZero:
+    if (isRV64())
+      return generateImmOutOfRangeError(Operands, ErrorInfo, 1, (1 << 6) - 1);
+    return generateImmOutOfRangeError(Operands, ErrorInfo, 1, (1 << 5) - 1);
   case Match_InvalidUImm5:
     return generateImmOutOfRangeError(Operands, ErrorInfo, 0, (1 << 5) - 1);
-  case Match_InvalidUImm5NonZero:
-    return generateImmOutOfRangeError(Operands, ErrorInfo, 1, (1 << 5) - 1);
   case Match_InvalidSImm6:
     return generateImmOutOfRangeError(Operands, ErrorInfo, -(1 << 5),
                                       (1 << 5) - 1);
Index: lib/Target/RISCV/RISCVInstrInfoC.td
===================================================================
--- lib/Target/RISCV/RISCVInstrInfoC.td
+++ lib/Target/RISCV/RISCVInstrInfoC.td
@@ -13,12 +13,6 @@
 // Operand definitions.
 //===----------------------------------------------------------------------===//
 
-def uimm5nonzero : Operand<XLenVT>,
-                   ImmLeaf<XLenVT, [{return isUInt<5>(Imm) && (Imm != 0);}]> {
-  let ParserMatchClass = UImmAsmOperand<5, "NonZero">;
-  let DecoderMethod = "decodeUImmOperand<5>";
-}
-
 def simm6 : Operand<XLenVT>, ImmLeaf<XLenVT, [{return isInt<6>(Imm);}]> {
   let ParserMatchClass = SImmAsmOperand<6>;
   let EncoderMethod = "getImmOpValue";
@@ -95,6 +89,22 @@
   let DecoderMethod = "decodeSImmOperandAndLsl1<12>";
 }
 
+def UImmLog2XLenNonZeroAsmOperand : AsmOperandClass {
+  let Name = "UImmLog2XLenNonZero";
+  let RenderMethod = "addImmOperands";
+  let DiagnosticType = "InvalidUImmLog2XLenNonZero";
+}
+
+def uimmlog2xlennonzero : Operand<XLenVT>, ImmLeaf<XLenVT, [{
+  if (Subtarget->is64Bit())
+    return isUInt<6>(Imm) && (Imm != 0);
+  return isUInt<5>(Imm) && (Imm != 0);
+}]> {
+  let ParserMatchClass = UImmLog2XLenNonZeroAsmOperand;
+  // TODO: should ensure invalid shamt is rejected when decoding.
+  let DecoderMethod = "decodeUImmOperand<6>";
+}
+
 //===----------------------------------------------------------------------===//
 // Instruction Class Templates
 //===----------------------------------------------------------------------===//
@@ -290,8 +300,8 @@
   let Inst{6-2} = imm{4-0};
 }
 
-def C_SRLI : Shift_right<0b00, "c.srli", GPRC, uimm5nonzero>;
-def C_SRAI : Shift_right<0b01, "c.srai", GPRC, uimm5nonzero>;
+def C_SRLI : Shift_right<0b00, "c.srli", GPRC, uimmlog2xlennonzero>;
+def C_SRAI : Shift_right<0b01, "c.srai", GPRC, uimmlog2xlennonzero>;
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
 def C_ANDI : RVInst16CB<0b100, 0b01, (outs GPRC:$rs1_wb), (ins GPRC:$rs1, simm6:$imm),
@@ -323,7 +333,7 @@
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
 def C_SLLI : RVInst16CI<0b000, 0b10, (outs GPRNoX0:$rd_wb),
-                        (ins GPRNoX0:$rd, uimm5nonzero:$imm),
+                        (ins GPRNoX0:$rd, uimmlog2xlennonzero:$imm),
                         "c.slli" ,"$rd, $imm"> {
   let Constraints = "$rd = $rd_wb";
   let Inst{6-2} = imm{4-0};
Index: test/MC/RISCV/rv32c-invalid.s
===================================================================
--- test/MC/RISCV/rv32c-invalid.s
+++ test/MC/RISCV/rv32c-invalid.s
@@ -38,7 +38,7 @@
 
 # Out of range immediates
 
-## uimm5nonzero
+## uimmlog2xlennonzero
 c.slli t0, 64 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 31]
 c.srli a0, 32 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 31]
 c.srai a0, 0  # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 31]
Index: test/MC/RISCV/rv64c-invalid.s
===================================================================
--- test/MC/RISCV/rv64c-invalid.s
+++ test/MC/RISCV/rv64c-invalid.s
@@ -12,6 +12,11 @@
 
 # Out of range immediates
 
+## uimmlog2xlennonzero
+c.slli t0, 64 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 63]
+c.srli a0, -1 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 63]
+c.srai a0, 0  # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 63]
+
 ## simm6
 c.addiw t0, -33 # CHECK: :[[@LINE]]:13: error: immediate must be an integer in the range [-32, 31]
 c.addiw t0, 32 # CHECK: :[[@LINE]]:13: error: immediate must be an integer in the range [-32, 31]
Index: test/MC/RISCV/rv64c-valid.s
===================================================================
--- test/MC/RISCV/rv64c-valid.s
+++ test/MC/RISCV/rv64c-valid.s
@@ -31,3 +31,13 @@
 # CHECK-INST: c.addiw  a3, 31
 # CHECK: encoding: [0xfd,0x26]
 c.addiw  a3, 31
+
+# CHECK-INST: c.slli  s0, 1
+# CHECK: encoding: [0x06,0x04]
+c.slli  s0, 1
+# CHECK-INST: c.srli  a3, 63
+# CHECK: encoding: [0xfd,0x92]
+c.srli  a3, 63
+# CHECK-INST: c.srai  a2, 63
+# CHECK: encoding: [0x7d,0x96]
+c.srai  a2, 63