diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -197,6 +197,14 @@
     setTruncStoreAction(MVT::f64, MVT::f16, Expand);
   }
 
+  if (Subtarget.is64Bit() &&
+      !(Subtarget.hasStdExtD() || Subtarget.hasStdExtF())) {
+    setOperationAction(ISD::FP_TO_UINT, MVT::i32, Custom);
+    setOperationAction(ISD::FP_TO_SINT, MVT::i32, Custom);
+    setOperationAction(ISD::STRICT_FP_TO_UINT, MVT::i32, Custom);
+    setOperationAction(ISD::STRICT_FP_TO_SINT, MVT::i32, Custom);
+  }
+
   setOperationAction(ISD::GlobalAddress, XLenVT, Custom);
   setOperationAction(ISD::BlockAddress, XLenVT, Custom);
   setOperationAction(ISD::ConstantPool, XLenVT, Custom);
@@ -904,6 +912,32 @@
   switch (N->getOpcode()) {
   default:
     llvm_unreachable("Don't know how to custom type legalize this operation!");
+  case ISD::STRICT_FP_TO_SINT:
+  case ISD::STRICT_FP_TO_UINT:
+  case ISD::FP_TO_SINT:
+  case ISD::FP_TO_UINT: {
+    bool IsStrict = N->isStrictFPOpcode();
+    assert(N->getValueType(0) == MVT::i32 && Subtarget.is64Bit() &&
+           "Unexpected custom legalisation");
+    SDValue Op0 = IsStrict ? N->getOperand(1) : N->getOperand(0);
+    RTLIB::Libcall LC;
+    if (N->getOpcode() == ISD::FP_TO_SINT ||
+        N->getOpcode() == ISD::STRICT_FP_TO_SINT)
+      LC = RTLIB::getFPTOSINT(Op0.getValueType(), N->getValueType(0));
+    else
+      LC = RTLIB::getFPTOUINT(Op0.getValueType(), N->getValueType(0));
+    MakeLibCallOptions CallOptions;
+    EVT OpVT = Op0.getValueType();
+    CallOptions.setTypeListBeforeSoften(OpVT, N->getValueType(0), true);
+    SDValue Chain = IsStrict ? N->getOperand(0) : SDValue();
+    SDValue Result;
+    std::tie(Result, Chain) =
+        makeLibCall(DAG, LC, N->getValueType(0), Op0, CallOptions, DL, Chain);
+    Results.push_back(Result);
+    if (IsStrict)
+      Results.push_back(Chain);
+    break;
+  }
   case ISD::READCYCLECOUNTER: {
     assert(!Subtarget.is64Bit() &&
            "READCYCLECOUNTER only has custom type legalization on riscv32");
diff --git a/llvm/test/CodeGen/RISCV/rv64i-single-softfloat.ll b/llvm/test/CodeGen/RISCV/rv64i-single-softfloat.ll
--- a/llvm/test/CodeGen/RISCV/rv64i-single-softfloat.ll
+++ b/llvm/test/CodeGen/RISCV/rv64i-single-softfloat.ll
@@ -174,7 +174,7 @@
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi sp, sp, -16
 ; RV64I-NEXT:    sd ra, 8(sp)
-; RV64I-NEXT:    call __fixsfdi
+; RV64I-NEXT:    call __fixsfsi
 ; RV64I-NEXT:    ld ra, 8(sp)
 ; RV64I-NEXT:    addi sp, sp, 16
 ; RV64I-NEXT:    ret
@@ -187,7 +187,7 @@
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi sp, sp, -16
 ; RV64I-NEXT:    sd ra, 8(sp)
-; RV64I-NEXT:    call __fixunssfdi
+; RV64I-NEXT:    call __fixunssfsi
 ; RV64I-NEXT:    ld ra, 8(sp)
 ; RV64I-NEXT:    addi sp, sp, 16
 ; RV64I-NEXT:    ret
@@ -710,3 +710,123 @@
   %conv = fptrunc double %a to float
   ret float %conv
 }
+
+define i32 @fp32_to_ui32(float %a) nounwind {
+; RV64I-LABEL: fp32_to_ui32:
+; RV64I:       # %bb.0: # %entry
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    call __fixunssfsi
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+entry:
+  %conv = fptoui float %a to i32
+  ret i32 %conv
+}
+
+define i32 @fp32_to_si32(float %a) nounwind  {
+; RV64I-LABEL: fp32_to_si32:
+; RV64I:       # %bb.0: # %entry
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    call __fixsfsi
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+entry:
+  %conv = fptosi float %a to i32
+  ret i32 %conv
+}
+
+define i32 @fp64_to_ui32(double %a) nounwind {
+; RV64I-LABEL: fp64_to_ui32:
+; RV64I:       # %bb.0: # %entry
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    call __fixunsdfsi
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+entry:
+  %conv = fptoui double %a to i32
+  ret i32 %conv
+}
+
+define i32 @fp64_to_si32(double %a) nounwind {
+; RV64I-LABEL: fp64_to_si32:
+; RV64I:       # %bb.0: # %entry
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    call __fixdfsi
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+entry:
+  %conv = fptosi double %a to i32
+  ret i32 %conv
+}
+
+
+
+declare i32 @llvm.experimental.constrained.fptoui.i32.f32(float, metadata)
+declare i32 @llvm.experimental.constrained.fptosi.i32.f32(float, metadata)
+declare i32 @llvm.experimental.constrained.fptosi.i32.f64(double, metadata)
+declare i32 @llvm.experimental.constrained.fptoui.i32.f64(double, metadata)
+
+define i32 @strict_fp32_to_ui32(float %a) nounwind strictfp {
+; RV64I-LABEL: strict_fp32_to_ui32:
+; RV64I:       # %bb.0: # %entry
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    call __fixunssfsi
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+entry:
+  %conv = tail call i32 @llvm.experimental.constrained.fptoui.i32.f32(float %a, metadata !"fpexcept.strict")
+  ret i32 %conv
+}
+
+define i32 @strict_fp32_to_si32(float %a) nounwind strictfp {
+; RV64I-LABEL: strict_fp32_to_si32:
+; RV64I:       # %bb.0: # %entry
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    call __fixsfsi
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+entry:
+  %conv = tail call i32 @llvm.experimental.constrained.fptosi.i32.f32(float %a, metadata !"fpexcept.strict")
+  ret i32 %conv
+}
+
+define i32 @strict_fp64_to_ui32(double %a) nounwind strictfp {
+; RV64I-LABEL: strict_fp64_to_ui32:
+; RV64I:       # %bb.0: # %entry
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    call __fixunsdfsi
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+entry:
+  %conv = tail call i32 @llvm.experimental.constrained.fptoui.i32.f64(double %a, metadata !"fpexcept.strict")
+  ret i32 %conv
+}
+
+define i32 @struct_fp64_to_si32(double %a) nounwind strictfp {
+; RV64I-LABEL: struct_fp64_to_si32:
+; RV64I:       # %bb.0: # %entry
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    call __fixdfsi
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+entry:
+  %conv = tail call i32 @llvm.experimental.constrained.fptosi.i32.f64(double %a, metadata !"fpexcept.strict")
+  ret i32 %conv
+}
+