[LegalizeTypes] Add SoftenFloatResult support for STRICT_SINT_TO_FP/STRICT_UINT_TO_FP

[wwei]

Summary

Some target like arm/riscv with soft-float will have compiling crash when using -fno-unsafe-math-optimization option.
This patch will add the missing strict FP support to SoftenFloatRes_XINT_TO_FP.

[craig.topper]

LGTM

llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp

#endif
     case ISD::STRICT_FSUB:
     case ISD::FSUB:        R = SoftenFloatRes_FSUB(N); break;
     case ISD::STRICT_FTRUNC:
     case ISD::FTRUNC:      R = SoftenFloatRes_FTRUNC(N); break;
     case ISD::LOAD:        R = SoftenFloatRes_LOAD(N); break;
     case ISD::ATOMIC_SWAP: R = BitcastToInt_ATOMIC_SWAP(N); break;
     case ISD::SELECT:      R = SoftenFloatRes_SELECT(N); break;
     case ISD::SELECT_CC:   R = SoftenFloatRes_SELECT_CC(N); break;
+    case ISD::STRICT_SINT_TO_FP:
+    case ISD::STRICT_UINT_TO_FP:
     case ISD::SINT_TO_FP:
     case ISD::UINT_TO_FP:  R = SoftenFloatRes_XINT_TO_FP(N); break;
     case ISD::UNDEF:       R = SoftenFloatRes_UNDEF(N); break;
     case ISD::VAARG:       R = SoftenFloatRes_VAARG(N); break;
   }
 
   // If R is null, the sub-method took care of registering the result.
   if (R.getNode()) {
SDValue DAGTypeLegalizer::SoftenFloatRes_VAARG(SDNode *N) {
   // Legalized the chain result - switch anything that used the old chain to
   // use the new one.
   if (N != NewVAARG.getValue(1).getNode())
     ReplaceValueWith(SDValue(N, 1), NewVAARG.getValue(1));
   return NewVAARG;
 }
 
 SDValue DAGTypeLegalizer::SoftenFloatRes_XINT_TO_FP(SDNode *N) {
-  bool Signed = N->getOpcode() == ISD::SINT_TO_FP;
-  EVT SVT = N->getOperand(0).getValueType();
+  bool IsStrict = N->isStrictFPOpcode();
+  bool Signed = N->getOpcode() == ISD::SINT_TO_FP ||
+                N->getOpcode() == ISD::STRICT_SINT_TO_FP;
+  EVT SVT = N->getOperand(IsStrict ? 1 : 0).getValueType();
   EVT RVT = N->getValueType(0);
   EVT NVT = EVT();
   SDLoc dl(N);
 
   // If the input is not legal, eg: i1 -> fp, then it needs to be promoted to
   // a larger type, eg: i8 -> fp.  Even if it is legal, no libcall may exactly
   // match.  Look for an appropriate libcall.
   RTLIB::Libcall LC = RTLIB::UNKNOWN_LIBCALL;
   for (unsigned t = MVT::FIRST_INTEGER_VALUETYPE;
        t <= MVT::LAST_INTEGER_VALUETYPE && LC == RTLIB::UNKNOWN_LIBCALL; ++t) {
     NVT = (MVT::SimpleValueType)t;
     // The source needs to big enough to hold the operand.
     if (NVT.bitsGE(SVT))
       LC = Signed ? RTLIB::getSINTTOFP(NVT, RVT):RTLIB::getUINTTOFP (NVT, RVT);
   }
   assert(LC != RTLIB::UNKNOWN_LIBCALL && "Unsupported XINT_TO_FP!");
 
+  SDValue Chain = IsStrict ? N->getOperand(0) : SDValue();
   // Sign/zero extend the argument if the libcall takes a larger type.
   SDValue Op = DAG.getNode(Signed ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND, dl,
-                           NVT, N->getOperand(0));
+                           NVT, N->getOperand(IsStrict ? 1 : 0));
   TargetLowering::MakeLibCallOptions CallOptions;
   CallOptions.setSExt(Signed);
-  EVT OpsVT[1] = { N->getOperand(0).getValueType() };
-  CallOptions.setTypeListBeforeSoften(OpsVT, N->getValueType(0), true);
-  return TLI.makeLibCall(DAG, LC,
-                         TLI.getTypeToTransformTo(*DAG.getContext(), RVT),
-                         Op, CallOptions, dl).first;
+  CallOptions.setTypeListBeforeSoften(SVT, RVT, true);
+  std::pair<SDValue, SDValue> Tmp =
+      TLI.makeLibCall(DAG, LC, TLI.getTypeToTransformTo(*DAG.getContext(), RVT),
+                      Op, CallOptions, dl, Chain);
+
+  if (IsStrict)
+    ReplaceValueWith(SDValue(N, 1), Tmp.second);
+  return Tmp.first;
 }
 
 
 //===----------------------------------------------------------------------===//
 //  Convert Float Operand to Integer
 //===----------------------------------------------------------------------===//
 
 bool DAGTypeLegalizer::SoftenFloatOperand(SDNode *N, unsigned OpNo) {

llvm/test/CodeGen/ARM/fp-intrinsics.ll

 ; CHECK-LABEL: fpext_f32:
 ; CHECK-NODP: bl __aeabi_f2d
 ; CHECK-DP: vcvt.f64.f32
 define double @fpext_f32(float %x) #0 {
   %val = call double @llvm.experimental.constrained.fpext.f64.f32(float %x, metadata !"fpexcept.strict") #0
   ret double %val
 }
 
+; CHECK-LABEL: sitofp_f32_i32:
+; CHECK-NOSP: bl __aeabi_i2f
+; CHECK-SP: vcvt.f32.s32
+define float @sitofp_f32_i32(i32 %x) #0 {
+  %val = call float @llvm.experimental.constrained.sitofp.f32.i32(i32 %x, metadata !"round.tonearest", metadata !"fpexcept.strict") #0
+  ret float %val
+}
+
+; CHECK-LABEL: sitofp_f64_i32:
+; CHECK-NODP: bl __aeabi_i2d
+; CHECK-DP: vcvt.f64.s32
+define double @sitofp_f64_i32(i32 %x) #0 {
+  %val = call double @llvm.experimental.constrained.sitofp.f64.i32(i32 %x, metadata !"round.tonearest", metadata !"fpexcept.strict") #0
+  ret double %val
+}
+
 
 attributes #0 = { strictfp }
 
 declare float @llvm.experimental.constrained.fadd.f32(float, float, metadata, metadata)
 declare float @llvm.experimental.constrained.fsub.f32(float, float, metadata, metadata)
 declare float @llvm.experimental.constrained.fmul.f32(float, float, metadata, metadata)
 declare float @llvm.experimental.constrained.fdiv.f32(float, float, metadata, metadata)
 declare float @llvm.experimental.constrained.frem.f32(float, float, metadata, metadata)

 declare double @llvm.experimental.constrained.floor.f64(double, metadata)
 declare i32 @llvm.experimental.constrained.lround.f64(double, metadata)
 declare i32 @llvm.experimental.constrained.llround.f64(double, metadata)
 declare double @llvm.experimental.constrained.round.f64(double, metadata)
 declare double @llvm.experimental.constrained.trunc.f64(double, metadata)
 
 declare float @llvm.experimental.constrained.fptrunc.f32.f64(double, metadata, metadata)
 declare double @llvm.experimental.constrained.fpext.f64.f32(float, metadata)
+declare float @llvm.experimental.constrained.sitofp.f32.i32(i32, metadata, metadata)
+declare double @llvm.experimental.constrained.sitofp.f64.i32(i32, metadata, metadata)