[X86][GlobalISel] - Legalize And Select G_FPTOSI/G_SITOFP in X87 mode (llvm#137377)

pawan-nirpal-031 · web-flow · commit a4b9e82fc4b2 · 2025-06-02T16:43:39.000+02:00
Support legalization and selection of G_FPTOSI/G_SITOFP generic opcodes
in x87 mode.
diff --git a/llvm/include/llvm/CodeGen/GlobalISel/LegalizerInfo.h b/llvm/include/llvm/CodeGen/GlobalISel/LegalizerInfo.h
@@ -935,6 +935,16 @@ class LegalizeRuleSet {
                                      Types2);
   }
 
+  /// The instruction is custom when the predicate is true and type indexes 0
+  /// and 1 are all in their respective lists.
+  LegalizeRuleSet &
+  customForCartesianProduct(bool Pred, std::initializer_list<LLT> Types0,
+                            std::initializer_list<LLT> Types1) {
+    if (!Pred)
+      return *this;
+    return actionForCartesianProduct(LegalizeAction::Custom, Types0, Types1);
+  }
+
   /// Unconditionally custom lower.
   LegalizeRuleSet &custom() {
     return customIf(always);
diff --git a/llvm/lib/Target/X86/GISel/X86InstructionSelector.cpp b/llvm/lib/Target/X86/GISel/X86InstructionSelector.cpp
@@ -364,7 +364,7 @@ bool X86InstructionSelector::select(MachineInstr &I) {
   MachineRegisterInfo &MRI = MF.getRegInfo();
 
   unsigned Opcode = I.getOpcode();
-  if (!isPreISelGenericOpcode(Opcode)) {
+  if (!isPreISelGenericOpcode(Opcode) && !I.isPreISelOpcode()) {
     // Certain non-generic instructions also need some special handling.
 
     if (Opcode == TargetOpcode::LOAD_STACK_GUARD)
diff --git a/llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp b/llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp
@@ -490,31 +490,25 @@ X86LegalizerInfo::X86LegalizerInfo(const X86Subtarget &STI,
       });
 
   getActionDefinitionsBuilder(G_SITOFP)
-      .legalIf([=](const LegalityQuery &Query) {
-        return (HasSSE1 &&
-                (typePairInSet(0, 1, {{s32, s32}})(Query) ||
-                 (Is64Bit && typePairInSet(0, 1, {{s32, s64}})(Query)))) ||
-               (HasSSE2 &&
-                (typePairInSet(0, 1, {{s64, s32}})(Query) ||
-                 (Is64Bit && typePairInSet(0, 1, {{s64, s64}})(Query))));
-      })
-      .clampScalar(1, s32, sMaxScalar)
+      .legalFor(HasSSE1, {{s32, s32}})
+      .legalFor(HasSSE1 && Is64Bit, {{s32, s64}})
+      .legalFor(HasSSE2, {{s64, s32}})
+      .legalFor(HasSSE2 && Is64Bit, {{s64, s64}})
+      .clampScalar(1, (UseX87 && !HasSSE1) ? s16 : s32, sMaxScalar)
       .widenScalarToNextPow2(1)
+      .customForCartesianProduct(UseX87, {s32, s64, s80}, {s16, s32, s64})
       .clampScalar(0, s32, HasSSE2 ? s64 : s32)
       .widenScalarToNextPow2(0);
 
   getActionDefinitionsBuilder(G_FPTOSI)
-      .legalIf([=](const LegalityQuery &Query) {
-        return (HasSSE1 &&
-                (typePairInSet(0, 1, {{s32, s32}})(Query) ||
-                 (Is64Bit && typePairInSet(0, 1, {{s64, s32}})(Query)))) ||
-               (HasSSE2 &&
-                (typePairInSet(0, 1, {{s32, s64}})(Query) ||
-                 (Is64Bit && typePairInSet(0, 1, {{s64, s64}})(Query))));
-      })
-      .clampScalar(1, s32, HasSSE2 ? s64 : s32)
+      .legalFor(HasSSE1, {{s32, s32}})
+      .legalFor(HasSSE1 && Is64Bit, {{s64, s32}})
+      .legalFor(HasSSE2, {{s32, s64}})
+      .legalFor(HasSSE2 && Is64Bit, {{s64, s64}})
+      .clampScalar(0, (UseX87 && !HasSSE1) ? s16 : s32, sMaxScalar)
       .widenScalarToNextPow2(0)
-      .clampScalar(0, s32, sMaxScalar)
+      .customForCartesianProduct(UseX87, {s16, s32, s64}, {s32, s64, s80})
+      .clampScalar(1, s32, HasSSE2 ? s64 : s32)
       .widenScalarToNextPow2(1);
 
   // For G_UITOFP and G_FPTOUI without AVX512, we have to custom legalize types
@@ -671,10 +665,70 @@ bool X86LegalizerInfo::legalizeCustom(LegalizerHelper &Helper, MachineInstr &MI,
     return legalizeUITOFP(MI, MRI, Helper);
   case TargetOpcode::G_STORE:
     return legalizeNarrowingStore(MI, MRI, Helper);
+  case TargetOpcode::G_SITOFP:
+    return legalizeSITOFP(MI, MRI, Helper);
+  case TargetOpcode::G_FPTOSI:
+    return legalizeFPTOSI(MI, MRI, Helper);
   }
   llvm_unreachable("expected switch to return");
 }
 
+bool X86LegalizerInfo::legalizeSITOFP(MachineInstr &MI,
+                                      MachineRegisterInfo &MRI,
+                                      LegalizerHelper &Helper) const {
+  MachineIRBuilder &MIRBuilder = Helper.MIRBuilder;
+  MachineFunction &MF = *MI.getMF();
+  auto [Dst, DstTy, Src, SrcTy] = MI.getFirst2RegLLTs();
+
+  assert((SrcTy.getSizeInBits() == 16 || SrcTy.getSizeInBits() == 32 ||
+          SrcTy.getSizeInBits() == 64) &&
+         "Unexpected source type for SITOFP in X87 mode.");
+
+  TypeSize MemSize = SrcTy.getSizeInBytes();
+  MachinePointerInfo PtrInfo;
+  Align Alignmt = Helper.getStackTemporaryAlignment(SrcTy);
+  auto SlotPointer = Helper.createStackTemporary(MemSize, Alignmt, PtrInfo);
+  MachineMemOperand *StoreMMO = MF.getMachineMemOperand(
+      PtrInfo, MachineMemOperand::MOStore, MemSize, Align(MemSize));
+
+  // Store the integer value on the FPU stack.
+  MIRBuilder.buildStore(Src, SlotPointer, *StoreMMO);
+
+  MachineMemOperand *LoadMMO = MF.getMachineMemOperand(
+      PtrInfo, MachineMemOperand::MOLoad, MemSize, Align(MemSize));
+  MIRBuilder.buildInstr(X86::G_FILD)
+      .addDef(Dst)
+      .addUse(SlotPointer.getReg(0))
+      .addMemOperand(LoadMMO);
+
+  MI.eraseFromParent();
+  return true;
+}
+
+bool X86LegalizerInfo::legalizeFPTOSI(MachineInstr &MI,
+                                      MachineRegisterInfo &MRI,
+                                      LegalizerHelper &Helper) const {
+  MachineFunction &MF = *MI.getMF();
+  MachineIRBuilder &MIRBuilder = Helper.MIRBuilder;
+  auto [Dst, DstTy, Src, SrcTy] = MI.getFirst2RegLLTs();
+
+  TypeSize MemSize = DstTy.getSizeInBytes();
+  MachinePointerInfo PtrInfo;
+  Align Alignmt = Helper.getStackTemporaryAlignment(DstTy);
+  auto SlotPointer = Helper.createStackTemporary(MemSize, Alignmt, PtrInfo);
+  MachineMemOperand *StoreMMO = MF.getMachineMemOperand(
+      PtrInfo, MachineMemOperand::MOStore, MemSize, Align(MemSize));
+
+  MIRBuilder.buildInstr(X86::G_FIST)
+      .addUse(Src)
+      .addUse(SlotPointer.getReg(0))
+      .addMemOperand(StoreMMO);
+
+  MIRBuilder.buildLoad(Dst, SlotPointer, PtrInfo, Align(MemSize));
+  MI.eraseFromParent();
+  return true;
+}
+
 bool X86LegalizerInfo::legalizeBuildVector(MachineInstr &MI,
                                            MachineRegisterInfo &MRI,
                                            LegalizerHelper &Helper) const {
diff --git a/llvm/lib/Target/X86/GISel/X86LegalizerInfo.h b/llvm/lib/Target/X86/GISel/X86LegalizerInfo.h
@@ -48,6 +48,12 @@ class X86LegalizerInfo : public LegalizerInfo {
 
   bool legalizeNarrowingStore(MachineInstr &MI, MachineRegisterInfo &MRI,
                               LegalizerHelper &Helper) const;
+
+  bool legalizeSITOFP(MachineInstr &MI, MachineRegisterInfo &MRI,
+                      LegalizerHelper &Helper) const;
+
+  bool legalizeFPTOSI(MachineInstr &MI, MachineRegisterInfo &MRI,
+                      LegalizerHelper &Helper) const;
 };
 } // namespace llvm
 #endif
diff --git a/llvm/lib/Target/X86/GISel/X86RegisterBankInfo.cpp b/llvm/lib/Target/X86/GISel/X86RegisterBankInfo.cpp
@@ -111,6 +111,7 @@ bool X86RegisterBankInfo::onlyUsesFP(const MachineInstr &MI,
   case TargetOpcode::G_FPTOSI:
   case TargetOpcode::G_FPTOUI:
   case TargetOpcode::G_FCMP:
+  case X86::G_FIST:
   case TargetOpcode::G_LROUND:
   case TargetOpcode::G_LLROUND:
   case TargetOpcode::G_INTRINSIC_TRUNC:
@@ -129,6 +130,7 @@ bool X86RegisterBankInfo::onlyDefinesFP(const MachineInstr &MI,
   switch (MI.getOpcode()) {
   case TargetOpcode::G_SITOFP:
   case TargetOpcode::G_UITOFP:
+  case X86::G_FILD:
     return true;
   default:
     break;
@@ -296,6 +298,16 @@ X86RegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
     // VECRReg)
     getInstrPartialMappingIdxs(MI, MRI, /* isFP= */ true, OpRegBankIdx);
     break;
+  case X86::G_FIST:
+  case X86::G_FILD: {
+    auto &Op0 = MI.getOperand(0);
+    auto &Op1 = MI.getOperand(1);
+    const LLT Ty0 = MRI.getType(Op0.getReg());
+    const LLT Ty1 = MRI.getType(Op1.getReg());
+    OpRegBankIdx[0] = getPartialMappingIdx(MI, Ty0, /* isFP= */ true);
+    OpRegBankIdx[1] = getPartialMappingIdx(MI, Ty1, /* isFP= */ false);
+    break;
+  }
   case TargetOpcode::G_SITOFP:
   case TargetOpcode::G_FPTOSI:
   case TargetOpcode::G_UITOFP:
diff --git a/llvm/lib/Target/X86/X86InstrFragments.td b/llvm/lib/Target/X86/X86InstrFragments.td
@@ -844,13 +844,24 @@ def X86fldf80 : PatFrag<(ops node:$ptr), (X86fld node:$ptr), [{
 
 def X86fild16 : PatFrag<(ops node:$ptr), (X86fild node:$ptr), [{
   return cast<MemIntrinsicSDNode>(N)->getMemoryVT() == MVT::i16;
-}]>;
+}]> {
+  let IsLoad = true;
+  let MemoryVT = i16;
+}
+
 def X86fild32 : PatFrag<(ops node:$ptr), (X86fild node:$ptr), [{
   return cast<MemIntrinsicSDNode>(N)->getMemoryVT() == MVT::i32;
-}]>;
+}]> {
+  let IsLoad = true;
+  let MemoryVT = i32;
+}
+
 def X86fild64 : PatFrag<(ops node:$ptr), (X86fild node:$ptr), [{
   return cast<MemIntrinsicSDNode>(N)->getMemoryVT() == MVT::i64;
-}]>;
+}]> {
+  let IsLoad = true;
+  let MemoryVT = i64;
+}
 
 def X86fist32 : PatFrag<(ops node:$val, node:$ptr),
                         (X86fist node:$val, node:$ptr), [{
@@ -865,15 +876,26 @@ def X86fist64 : PatFrag<(ops node:$val, node:$ptr),
 def X86fp_to_i16mem : PatFrag<(ops node:$val, node:$ptr),
                               (X86fp_to_mem node:$val, node:$ptr), [{
   return cast<MemIntrinsicSDNode>(N)->getMemoryVT() == MVT::i16;
-}]>;
+}]> {
+  let IsStore = true;
+  let MemoryVT = i16;
+}
+
 def X86fp_to_i32mem : PatFrag<(ops node:$val, node:$ptr),
                               (X86fp_to_mem node:$val, node:$ptr), [{
   return cast<MemIntrinsicSDNode>(N)->getMemoryVT() == MVT::i32;
-}]>;
+}]> {
+  let IsStore = true;
+  let MemoryVT = i32;
+}
+
 def X86fp_to_i64mem : PatFrag<(ops node:$val, node:$ptr),
                               (X86fp_to_mem node:$val, node:$ptr), [{
   return cast<MemIntrinsicSDNode>(N)->getMemoryVT() == MVT::i64;
-}]>;
+}]> {
+  let IsStore = true;
+  let MemoryVT = i64;
+}
 
 //===----------------------------------------------------------------------===//
 // FPStack pattern fragments
diff --git a/llvm/lib/Target/X86/X86InstrGISel.td b/llvm/lib/Target/X86/X86InstrGISel.td
@@ -0,0 +1,31 @@
+//===- X86InstrGISel.td - X86 GISel target specific opcodes -*- tablegen -*===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// X86 GlobalISel target pseudo instruction definitions. This is kept
+// separately from the other tablegen files for organizational purposes, but
+// share the same infrastructure.
+//
+//===----------------------------------------------------------------------===//
+
+class X86GenericInstruction : GenericInstruction { let Namespace = "X86"; }
+
+def G_FILD : X86GenericInstruction {
+  let OutOperandList = (outs type0:$dst);
+  let InOperandList = (ins ptype1:$src);
+  let hasSideEffects = false;
+  let mayLoad = true;
+}
+def G_FIST : X86GenericInstruction {
+  let OutOperandList = (outs);
+  let InOperandList = (ins type0:$src1, ptype1:$src2);
+  let hasSideEffects = false;
+  let mayStore = true;
+}
+
+def : GINodeEquiv<G_FILD, X86fild>;
+def : GINodeEquiv<G_FIST, X86fp_to_mem>;
diff --git a/llvm/lib/Target/X86/X86InstrInfo.td b/llvm/lib/Target/X86/X86InstrInfo.td
@@ -37,6 +37,11 @@ include "X86InstrFormats.td"
 //
 include "X86InstrUtils.td"
 
+//===----------------------------------------------------------------------===//
+// Global ISel
+//
+include "X86InstrGISel.td"
+
 //===----------------------------------------------------------------------===//
 // Subsystems.
 //===----------------------------------------------------------------------===//
diff --git a/llvm/test/CodeGen/X86/GlobalISel/isel-fp64-to-sint-x86.mir b/llvm/test/CodeGen/X86/GlobalISel/isel-fp64-to-sint-x86.mir
diff --git a/llvm/test/CodeGen/X86/GlobalISel/isel-sint-to-fp64-x86.mir b/llvm/test/CodeGen/X86/GlobalISel/isel-sint-to-fp64-x86.mir
diff --git a/llvm/test/CodeGen/X86/isel-fp-to-sint-x87.ll b/llvm/test/CodeGen/X86/isel-fp-to-sint-x87.ll
diff --git a/llvm/test/CodeGen/X86/isel-sint-to-fp-x87.ll b/llvm/test/CodeGen/X86/isel-sint-to-fp-x87.ll
