Revert "codegen: explicitly handle Float16 intrinsics (#45249)" (#45627)

This reverts commit eb82f18.

Author: KristofferC

src/APInt-C.cpp

@@ -316,7 +316,7 @@ void LLVMByteSwap(unsigned numbits, integerPart *pa, integerPart *pr) {
 void LLVMFPtoInt(unsigned numbits, void *pa, unsigned onumbits, integerPart *pr, bool isSigned, bool *isExact) {
     double Val;
     if (numbits == 16)
-        Val = julia__gnu_h2f_ieee(*(uint16_t*)pa);
+        Val = __gnu_h2f_ieee(*(uint16_t*)pa);
     else if (numbits == 32)
         Val = *(float*)pa;
     else if (numbits == 64)
@@ -391,7 +391,7 @@ void LLVMSItoFP(unsigned numbits, integerPart *pa, unsigned onumbits, integerPar
         val = a.roundToDouble(true);
     }
     if (onumbits == 16)
-        *(uint16_t*)pr = julia__gnu_f2h_ieee(val);
+        *(uint16_t*)pr = __gnu_f2h_ieee(val);
     else if (onumbits == 32)
         *(float*)pr = val;
     else if (onumbits == 64)
@@ -408,7 +408,7 @@ void LLVMUItoFP(unsigned numbits, integerPart *pa, unsigned onumbits, integerPar
         val = a.roundToDouble(false);
     }
     if (onumbits == 16)
-        *(uint16_t*)pr = julia__gnu_f2h_ieee(val);
+        *(uint16_t*)pr = __gnu_f2h_ieee(val);
     else if (onumbits == 32)
         *(float*)pr = val;
     else if (onumbits == 64)

src/julia.expmap

@@ -37,6 +37,12 @@
     environ;
     __progname;
 
+    /* compiler run-time intrinsics */
+    __gnu_h2f_ieee;
+    __extendhfsf2;
+    __gnu_f2h_ieee;
+    __truncdfhf2;
+
   local:
     *;
 };

src/julia_internal.h

@@ -1522,18 +1522,8 @@ jl_sym_t *_jl_symbol(const char *str, size_t len) JL_NOTSAFEPOINT;
   #define JL_GC_ASSERT_LIVE(x) (void)(x)
 #endif
 
-JL_DLLEXPORT float julia__gnu_h2f_ieee(uint16_t param) JL_NOTSAFEPOINT;
-JL_DLLEXPORT uint16_t julia__gnu_f2h_ieee(float param) JL_NOTSAFEPOINT;
-JL_DLLEXPORT uint16_t julia__truncdfhf2(double param) JL_NOTSAFEPOINT;
-//JL_DLLEXPORT double julia__extendhfdf2(uint16_t n) JL_NOTSAFEPOINT;
-//JL_DLLEXPORT int32_t julia__fixhfsi(uint16_t n) JL_NOTSAFEPOINT;
-//JL_DLLEXPORT int64_t julia__fixhfdi(uint16_t n) JL_NOTSAFEPOINT;
-//JL_DLLEXPORT uint32_t julia__fixunshfsi(uint16_t n) JL_NOTSAFEPOINT;
-//JL_DLLEXPORT uint64_t julia__fixunshfdi(uint16_t n) JL_NOTSAFEPOINT;
-//JL_DLLEXPORT uint16_t julia__floatsihf(int32_t n) JL_NOTSAFEPOINT;
-//JL_DLLEXPORT uint16_t julia__floatdihf(int64_t n) JL_NOTSAFEPOINT;
-//JL_DLLEXPORT uint16_t julia__floatunsihf(uint32_t n) JL_NOTSAFEPOINT;
-//JL_DLLEXPORT uint16_t julia__floatundihf(uint64_t n) JL_NOTSAFEPOINT;
+float __gnu_h2f_ieee(uint16_t param) JL_NOTSAFEPOINT;
+uint16_t __gnu_f2h_ieee(float param) JL_NOTSAFEPOINT;
 
 #ifdef __cplusplus
 }

src/llvm-demote-float16.cpp

@@ -18,7 +18,6 @@
 
 #include "support/dtypes.h"
 
-#include <llvm/Pass.h>
 #include <llvm/IR/IRBuilder.h>
 #include <llvm/IR/LegacyPassManager.h>
 #include <llvm/IR/PassManager.h>
@@ -29,193 +28,15 @@ using namespace llvm;
 
 namespace {
 
-inline AttributeSet getFnAttrs(const AttributeList &Attrs)
-{
-#if JL_LLVM_VERSION >= 140000
-    return Attrs.getFnAttrs();
-#else
-    return Attrs.getFnAttributes();
-#endif
-}
-
-inline AttributeSet getRetAttrs(const AttributeList &Attrs)
-{
-#if JL_LLVM_VERSION >= 140000
-    return Attrs.getRetAttrs();
-#else
-    return Attrs.getRetAttributes();
-#endif
-}
-
-static Instruction *replaceIntrinsicWith(IntrinsicInst *call, Type *RetTy, ArrayRef<Value*> args)
-{
-    Intrinsic::ID ID = call->getIntrinsicID();
-    assert(ID);
-    auto oldfType = call->getFunctionType();
-    auto nargs = oldfType->getNumParams();
-    assert(args.size() > nargs);
-    SmallVector<Type*, 8> argTys(nargs);
-    for (unsigned i = 0; i < nargs; i++)
-        argTys[i] = args[i]->getType();
-    auto newfType = FunctionType::get(RetTy, argTys, oldfType->isVarArg());
-
-    // Accumulate an array of overloaded types for the given intrinsic
-    // and compute the new name mangling schema
-    SmallVector<Type*, 4> overloadTys;
-    {
-        SmallVector<Intrinsic::IITDescriptor, 8> Table;
-        getIntrinsicInfoTableEntries(ID, Table);
-        ArrayRef<Intrinsic::IITDescriptor> TableRef = Table;
-        auto res = Intrinsic::matchIntrinsicSignature(newfType, TableRef, overloadTys);
-        assert(res == Intrinsic::MatchIntrinsicTypes_Match);
-        (void)res;
-        bool matchvararg = !Intrinsic::matchIntrinsicVarArg(newfType->isVarArg(), TableRef);
-        assert(matchvararg);
-        (void)matchvararg;
-    }
-    auto newF = Intrinsic::getDeclaration(call->getModule(), ID, overloadTys);
-    assert(newF->getFunctionType() == newfType);
-    newF->setCallingConv(call->getCallingConv());
-    assert(args.back() == call->getCalledFunction());
-    auto newCall = CallInst::Create(newF, args.drop_back(), "", call);
-    newCall->setTailCallKind(call->getTailCallKind());
-    auto old_attrs = call->getAttributes();
-    newCall->setAttributes(AttributeList::get(call->getContext(), getFnAttrs(old_attrs),
-                                              getRetAttrs(old_attrs), {})); // drop parameter attributes
-    return newCall;
-}
-
-
-static Value* CreateFPCast(Instruction::CastOps opcode, Value *V, Type *DestTy, IRBuilder<> &builder)
-{
-    Type *SrcTy = V->getType();
-    Type *RetTy = DestTy;
-    if (auto *VC = dyn_cast<Constant>(V)) {
-        // The input IR often has things of the form
-        //   fcmp olt half %0, 0xH7C00
-        // and we would like to avoid turning that constant into a call here
-        // if we can simply constant fold it to the new type.
-        VC = ConstantExpr::getCast(opcode, VC, DestTy, true);
-        if (VC)
-            return VC;
-    }
-    assert(SrcTy->isVectorTy() == DestTy->isVectorTy());
-    if (SrcTy->isVectorTy()) {
-        unsigned NumElems = cast<FixedVectorType>(SrcTy)->getNumElements();
-        assert(cast<FixedVectorType>(DestTy)->getNumElements() == NumElems && "Mismatched cast");
-        Value *NewV = UndefValue::get(DestTy);
-        RetTy = RetTy->getScalarType();
-        for (unsigned i = 0; i < NumElems; ++i) {
-            Value *I = builder.getInt32(i);
-            Value *Vi = builder.CreateExtractElement(V, I);
-            Vi = CreateFPCast(opcode, Vi, RetTy, builder);
-            NewV = builder.CreateInsertElement(NewV, Vi, I);
-        }
-        return NewV;
-    }
-    auto &M = *builder.GetInsertBlock()->getModule();
-    auto &ctx = M.getContext();
-    // Pick the Function to call in the Julia runtime
-    StringRef Name;
-    switch (opcode) {
-    case Instruction::FPExt:
-        // this is exact, so we only need one conversion
-        assert(SrcTy->isHalfTy());
-        Name = "julia__gnu_h2f_ieee";
-        RetTy = Type::getFloatTy(ctx);
-        break;
-    case Instruction::FPTrunc:
-        assert(DestTy->isHalfTy());
-        if (SrcTy->isFloatTy())
-            Name = "julia__gnu_f2h_ieee";
-        else if (SrcTy->isDoubleTy())
-            Name = "julia__truncdfhf2";
-        break;
-    // All F16 fit exactly in Int32 (-65504 to 65504)
-    case Instruction::FPToSI: JL_FALLTHROUGH;
-    case Instruction::FPToUI:
-        assert(SrcTy->isHalfTy());
-        Name = "julia__gnu_h2f_ieee";
-        RetTy = Type::getFloatTy(ctx);
-        break;
-    case Instruction::SIToFP: JL_FALLTHROUGH;
-    case Instruction::UIToFP:
-        assert(DestTy->isHalfTy());
-        Name = "julia__gnu_f2h_ieee";
-        SrcTy = Type::getFloatTy(ctx);
-        break;
-    default:
-        errs() << Instruction::getOpcodeName(opcode) << ' ';
-        V->getType()->print(errs());
-        errs() << " to ";
-        DestTy->print(errs());
-        errs() << " is an ";
-        llvm_unreachable("invalid cast");
-    }
-    if (Name.empty()) {
-        errs() << Instruction::getOpcodeName(opcode) << ' ';
-        V->getType()->print(errs());
-        errs() << " to ";
-        DestTy->print(errs());
-        errs() << " is an ";
-        llvm_unreachable("illegal cast");
-    }
-    // Coerce the source to the required size and type
-    auto T_int16 = Type::getInt16Ty(ctx);
-    if (SrcTy->isHalfTy())
-        SrcTy = T_int16;
-    if (opcode == Instruction::SIToFP)
-        V = builder.CreateSIToFP(V, SrcTy);
-    else if (opcode == Instruction::UIToFP)
-        V = builder.CreateUIToFP(V, SrcTy);
-    else
-        V = builder.CreateBitCast(V, SrcTy);
-    // Call our intrinsic
-    if (RetTy->isHalfTy())
-        RetTy = T_int16;
-    auto FT = FunctionType::get(RetTy, {SrcTy}, false);
-    FunctionCallee F = M.getOrInsertFunction(Name, FT);
-    Value *I = builder.CreateCall(F, {V});
-    // Coerce the result to the expected type
-    if (opcode == Instruction::FPToSI)
-        I = builder.CreateFPToSI(I, DestTy);
-    else if (opcode == Instruction::FPToUI)
-        I = builder.CreateFPToUI(I, DestTy);
-    else if (opcode == Instruction::FPExt)
-        I = builder.CreateFPCast(I, DestTy);
-    else
-        I = builder.CreateBitCast(I, DestTy);
-    return I;
-}
-
 static bool demoteFloat16(Function &F)
 {
     auto &ctx = F.getContext();
+    auto T_float16 = Type::getHalfTy(ctx);
     auto T_float32 = Type::getFloatTy(ctx);
 
     SmallVector<Instruction *, 0> erase;
     for (auto &BB : F) {
         for (auto &I : BB) {
-            // extend Float16 operands to Float32
-            bool Float16 = I.getType()->getScalarType()->isHalfTy();
-            for (size_t i = 0; !Float16 && i < I.getNumOperands(); i++) {
-                Value *Op = I.getOperand(i);
-                if (Op->getType()->getScalarType()->isHalfTy())
-                    Float16 = true;
-            }
-            if (!Float16)
-                continue;
-
-            if (auto CI = dyn_cast<CastInst>(&I)) {
-                if (CI->getOpcode() != Instruction::BitCast) { // aka !CI->isNoopCast(DL)
-                    IRBuilder<> builder(&I);
-                    Value *NewI = CreateFPCast(CI->getOpcode(), I.getOperand(0), I.getType(), builder);
-                    I.replaceAllUsesWith(NewI);
-                    erase.push_back(&I);
-                }
-                continue;
-            }
-
             switch (I.getOpcode()) {
             case Instruction::FNeg:
             case Instruction::FAdd:
@@ -226,9 +47,6 @@ static bool demoteFloat16(Function &F)
             case Instruction::FCmp:
                 break;
             default:
-                if (auto intrinsic = dyn_cast<IntrinsicInst>(&I))
-                    if (intrinsic->getIntrinsicID())
-                        break;
                 continue;
             }
 
@@ -240,67 +58,61 @@ static bool demoteFloat16(Function &F)
             IRBuilder<> builder(&I);
 
             // extend Float16 operands to Float32
-            // XXX: Calls to llvm.fma.f16 may need to go to f64 to be correct?
+            bool OperandsChanged = false;
             SmallVector<Value *, 2> Operands(I.getNumOperands());
             for (size_t i = 0; i < I.getNumOperands(); i++) {
                 Value *Op = I.getOperand(i);
-                if (Op->getType()->getScalarType()->isHalfTy()) {
-                    Op = CreateFPCast(Instruction::FPExt, Op, Op->getType()->getWithNewType(T_float32), builder);
+                if (Op->getType() == T_float16) {
+                    Op = builder.CreateFPExt(Op, T_float32);
+                    OperandsChanged = true;
                 }
                 Operands[i] = (Op);
             }
 
             // recreate the instruction if any operands changed,
             // truncating the result back to Float16
-            Value *NewI;
-            switch (I.getOpcode()) {
-            case Instruction::FNeg:
-                assert(Operands.size() == 1);
-                NewI = builder.CreateFNeg(Operands[0]);
-                break;
-            case Instruction::FAdd:
-                assert(Operands.size() == 2);
-                NewI = builder.CreateFAdd(Operands[0], Operands[1]);
-                break;
-            case Instruction::FSub:
-                assert(Operands.size() == 2);
-                NewI = builder.CreateFSub(Operands[0], Operands[1]);
-                break;
-            case Instruction::FMul:
-                assert(Operands.size() == 2);
-                NewI = builder.CreateFMul(Operands[0], Operands[1]);
-                break;
-            case Instruction::FDiv:
-                assert(Operands.size() == 2);
-                NewI = builder.CreateFDiv(Operands[0], Operands[1]);
-                break;
-            case Instruction::FRem:
-                assert(Operands.size() == 2);
-                NewI = builder.CreateFRem(Operands[0], Operands[1]);
-                break;
-            case Instruction::FCmp:
-                assert(Operands.size() == 2);
-                NewI = builder.CreateFCmp(cast<FCmpInst>(&I)->getPredicate(),
-                                          Operands[0], Operands[1]);
-                break;
-            default:
-                if (auto intrinsic = dyn_cast<IntrinsicInst>(&I)) {
-                    // XXX: this is not correct in general
-                    // some obvious failures include llvm.convert.to.fp16.*, llvm.vp.*to*, llvm.experimental.constrained.*to*, llvm.masked.*
-                    Type *RetTy = I.getType();
-                    if (RetTy->getScalarType()->isHalfTy())
-                        RetTy = RetTy->getWithNewType(T_float32);
-                    NewI = replaceIntrinsicWith(intrinsic, RetTy, Operands);
+            if (OperandsChanged) {
+                Value *NewI;
+                switch (I.getOpcode()) {
+                case Instruction::FNeg:
+                    assert(Operands.size() == 1);
+                    NewI = builder.CreateFNeg(Operands[0]);
+                    break;
+                case Instruction::FAdd:
+                    assert(Operands.size() == 2);
+                    NewI = builder.CreateFAdd(Operands[0], Operands[1]);
+                    break;
+                case Instruction::FSub:
+                    assert(Operands.size() == 2);
+                    NewI = builder.CreateFSub(Operands[0], Operands[1]);
+                    break;
+                case Instruction::FMul:
+                    assert(Operands.size() == 2);
+                    NewI = builder.CreateFMul(Operands[0], Operands[1]);
+                    break;
+                case Instruction::FDiv:
+                    assert(Operands.size() == 2);
+                    NewI = builder.CreateFDiv(Operands[0], Operands[1]);
+                    break;
+                case Instruction::FRem:
+                    assert(Operands.size() == 2);
+                    NewI = builder.CreateFRem(Operands[0], Operands[1]);
+                    break;
+                case Instruction::FCmp:
+                    assert(Operands.size() == 2);
+                    NewI = builder.CreateFCmp(cast<FCmpInst>(&I)->getPredicate(),
+                                              Operands[0], Operands[1]);
                     break;
+                default:
+                    abort();
                 }
-                abort();
+                cast<Instruction>(NewI)->copyMetadata(I);
+                cast<Instruction>(NewI)->copyFastMathFlags(&I);
+                if (NewI->getType() != I.getType())
+                    NewI = builder.CreateFPTrunc(NewI, I.getType());
+                I.replaceAllUsesWith(NewI);
+                erase.push_back(&I);
             }
-            cast<Instruction>(NewI)->copyMetadata(I);
-            cast<Instruction>(NewI)->copyFastMathFlags(&I);
-            if (NewI->getType() != I.getType())
-                NewI = CreateFPCast(Instruction::FPTrunc, NewI, I.getType(), builder);
-            I.replaceAllUsesWith(NewI);
-            erase.push_back(&I);
         }
     }