[SYCL] Add support for -foffload-fp32-prec-div/sqrt options.

clang/include/clang/Basic/DiagnosticCommonKinds.td

@@ -379,6 +379,11 @@ def err_ppc_impossible_musttail: Error<
 def err_aix_musttail_unsupported: Error<
   "'musttail' attribute is not supported on AIX">;
 
+def warn_acuracy_conflicts_with_explicit_offload_fp32_prec_option : Warning<
+  "floating point accuracy control '%0' conflicts with explicit target "
+  "precision option '%1'">,
+  InGroup<DiagGroup<"accuracy-conflicts-with-explicit-offload-fp32-prec-option">>;
+
 // Source manager
 def err_cannot_open_file : Error<"cannot open file '%0': %1">, DefaultFatal;
 def err_file_modified : Error<

clang/include/clang/Basic/FPOptions.def

@@ -30,4 +30,6 @@ OPTION(BFloat16ExcessPrecision, LangOptions::ExcessPrecisionKind, 2, Float16Exce
 OPTION(FPAccuracy, LangOptions::FPAccuracyKind, 3, BFloat16ExcessPrecision)
 OPTION(MathErrno, bool, 1, FPAccuracy)
 OPTION(ComplexRange, LangOptions::ComplexRangeKind, 2, MathErrno)
+OPTION(OffloadFP32PrecDi, bool, 1, ComplexRange)
+OPTION(OffloadFP32PrecSqrt, bool, 1, OffloadFP32PrecDi)
 #undef OPTION

clang/include/clang/Basic/LangOptions.def

@@ -372,6 +372,8 @@ BENIGN_ENUM_LANGOPT(FPEvalMethod, FPEvalMethodKind, 2, FEM_UnsetOnCommandLine, "
 ENUM_LANGOPT(Float16ExcessPrecision, ExcessPrecisionKind, 2, FPP_Standard, "Intermediate truncation behavior for Float16 arithmetic")
 ENUM_LANGOPT(BFloat16ExcessPrecision, ExcessPrecisionKind, 2, FPP_Standard, "Intermediate truncation behavior for BFloat16 arithmetic")
 BENIGN_ENUM_LANGOPT(FPAccuracy, FPAccuracyKind, 3, FPA_Default, "Accuracy for floating point operations and library functions")
+LANGOPT(OffloadFP32PrecDiv, 1, 1, "Return correctly rounded results of fdiv")
+LANGOPT(OffloadFP32PrecSqrt, 1, 1, "Return correctly rounded results of sqrt")
 LANGOPT(NoBitFieldTypeAlign , 1, 0, "bit-field type alignment")
 LANGOPT(HexagonQdsp6Compat , 1, 0, "hexagon-qdsp6 backward compatibility")
 LANGOPT(ObjCAutoRefCount , 1, 0, "Objective-C automated reference counting")

clang/include/clang/Driver/Options.td

@@ -1157,6 +1157,22 @@ defm cx_fortran_rules: BoolOptionWithoutMarshalling<"f", "cx-fortran-rules",
   NegFlag<SetFalse, [], [ClangOption, CC1Option], "Range reduction is disabled "
   "for complex arithmetic operations">>;
 
+ defm offload_fp32_prec_div: BoolOption<"f", "offload-fp32-prec-div",
+   LangOpts<"OffloadFP32PrecDiv">, DefaultTrue,
+   PosFlag<SetTrue, [], [ClangOption, CC1Option], "fdiv operations in offload device "
+   "code are required to return correctly rounded results.">,
+   NegFlag<SetFalse, [], [ClangOption, CC1Option], "fdiv operations in offload device "
+   "code are not required to return correctly rounded results.">>,
+   Group<f_Group>;
+
+ defm offload_fp32_prec_sqrt: BoolOption<"f", "offload-fp32-prec-sqrt",
+   LangOpts<"OffloadFP32PrecSqrt">, DefaultTrue,
+   PosFlag<SetTrue, [], [ClangOption, CC1Option], "sqrt operations in offload device "
+   "code are required to return correctly rounded results.">,
+   NegFlag<SetFalse, [], [ClangOption, CC1Option], "sqrt operations in offload device "
+   "code are not required to return correctly rounded results.">>,
+   Group<f_Group>;
+
 // OpenCL-only Options
 def cl_opt_disable : Flag<["-"], "cl-opt-disable">, Group<opencl_Group>,
   Visibility<[ClangOption, CC1Option]>,

clang/lib/CodeGen/CGBuiltin.cpp

@@ -521,13 +521,6 @@ static Function *getIntrinsic(CodeGenFunction &CGF, llvm::Value *Src0,
              : CGF.CGM.getIntrinsic(IntrinsicID, Src0->getType());
 }
 
-static bool hasAccuracyRequirement(CodeGenFunction &CGF, StringRef Name) {
-  if (!CGF.getLangOpts().FPAccuracyVal.empty())
-    return true;
-  auto FuncMapIt = CGF.getLangOpts().FPAccuracyFuncMap.find(Name.str());
-  return FuncMapIt != CGF.getLangOpts().FPAccuracyFuncMap.end();
-}
-
 static Function *emitMaybeIntrinsic(CodeGenFunction &CGF, const CallExpr *E,
                                     unsigned FPAccuracyIntrinsicID,
                                     unsigned IntrinsicID, llvm::Value *Src0,
@@ -546,7 +539,7 @@ static Function *emitMaybeIntrinsic(CodeGenFunction &CGF, const CallExpr *E,
             CGF.CGM.getContext().BuiltinInfo.getName(CGF.getCurrentBuiltinID());
         // Use fpbuiltin intrinsic only when needed.
         Func = getIntrinsic(CGF, Src0, FPAccuracyIntrinsicID, IntrinsicID,
-                            hasAccuracyRequirement(CGF, Name));
+                            CGF.hasAccuracyRequirement(Name));
       }
     }
   }
@@ -24099,6 +24092,7 @@ llvm::CallInst *CodeGenFunction::MaybeEmitFPBuiltinofFD(
             .Case("sincos", llvm::Intrinsic::fpbuiltin_sincos)
             .Case("exp10", llvm::Intrinsic::fpbuiltin_exp10)
             .Case("rsqrt", llvm::Intrinsic::fpbuiltin_rsqrt)
+            .Case("sqrt", llvm::Intrinsic::fpbuiltin_sqrt)
             .Default(0);
   } else {
     // The function has a clang builtin. Create an attribute for it
@@ -24200,7 +24194,8 @@ llvm::CallInst *CodeGenFunction::MaybeEmitFPBuiltinofFD(
   // a TU fp-accuracy requested.
   const LangOptions &LangOpts = getLangOpts();
   if (hasFuncNameRequestedFPAccuracy(Name, LangOpts) ||
-      !LangOpts.FPAccuracyVal.empty()) {
+      !LangOpts.FPAccuracyVal.empty() || !LangOpts.OffloadFP32PrecDiv ||
+      !LangOpts.OffloadFP32PrecSqrt) {
     llvm::Function *Func =
         CGM.getIntrinsic(FPAccuracyIntrinsicID, IRArgs[0]->getType());
     return CreateBuiltinCallWithAttr(*this, Name, Func, ArrayRef(IRArgs),

clang/lib/CodeGen/CGCall.cpp

@@ -1879,25 +1879,44 @@ void CodeGenModule::getDefaultFunctionFPAccuracyAttributes(
   // the 'FPAccuracyFuncMap'; if no accuracy is mapped to Name (FuncAttrs
   // is empty), then set its accuracy from the TU's accuracy value.
   if (!getLangOpts().FPAccuracyFuncMap.empty()) {
+    StringRef FPAccuracyVal;
     auto FuncMapIt = getLangOpts().FPAccuracyFuncMap.find(Name.str());
     if (FuncMapIt != getLangOpts().FPAccuracyFuncMap.end()) {
-      StringRef FPAccuracyVal = llvm::fp::getAccuracyForFPBuiltin(
-          ID, FuncType, convertFPAccuracy(FuncMapIt->second));
+      if (!getLangOpts().OffloadFP32PrecDiv && Name == "fdiv")
+        FPAccuracyVal = "2.5";
+      else if (!getLangOpts().OffloadFP32PrecSqrt && Name == "sqrt")
+        FPAccuracyVal = "3.0";
+      else
+        FPAccuracyVal = llvm::fp::getAccuracyForFPBuiltin(
+            ID, FuncType, convertFPAccuracy(FuncMapIt->second));
       assert(!FPAccuracyVal.empty() && "A valid accuracy value is expected");
       FuncAttrs.addAttribute("fpbuiltin-max-error", FPAccuracyVal);
       MD = llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
           Int32Ty, convertFPAccuracyToAspect(FuncMapIt->second)));
     }
   }
-  if (FuncAttrs.attrs().size() == 0)
+  if (FuncAttrs.attrs().size() == 0) {
     if (!getLangOpts().FPAccuracyVal.empty()) {
-      StringRef FPAccuracyVal = llvm::fp::getAccuracyForFPBuiltin(
-          ID, FuncType, convertFPAccuracy(getLangOpts().FPAccuracyVal));
+      StringRef FPAccuracyVal;
+      if (!getLangOpts().OffloadFP32PrecDiv && Name == "fdiv")
+        FPAccuracyVal = "2.5";
+      else if (!getLangOpts().OffloadFP32PrecSqrt && Name == "sqrt")
+        FPAccuracyVal = "3.0";
+      else
+        FPAccuracyVal = llvm::fp::getAccuracyForFPBuiltin(
+            ID, FuncType, convertFPAccuracy(getLangOpts().FPAccuracyVal));
       assert(!FPAccuracyVal.empty() && "A valid accuracy value is expected");
       FuncAttrs.addAttribute("fpbuiltin-max-error", FPAccuracyVal);
       MD = llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
           Int32Ty, convertFPAccuracyToAspect(getLangOpts().FPAccuracyVal)));
+    } else {
+      if (!getLangOpts().OffloadFP32PrecDiv && Name == "fdiv") {
+        FuncAttrs.addAttribute("fpbuiltin-max-error", "2.5");
+      } else if (!getLangOpts().OffloadFP32PrecSqrt && Name == "sqrt") {
+        FuncAttrs.addAttribute("fpbuiltin-max-error", "3.0");
+      }
     }
+  }
 }
 
 /// Add denormal-fp-math and denormal-fp-math-f32 as appropriate for the
@@ -5790,10 +5809,20 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   // Emit the actual call/invoke instruction.
   llvm::CallBase *CI;
   if (!InvokeDest) {
-    if (!getLangOpts().FPAccuracyFuncMap.empty() ||
-        !getLangOpts().FPAccuracyVal.empty()) {
-      const auto *FD = dyn_cast_if_present<FunctionDecl>(TargetDecl);
-      if (FD && FD->getNameInfo().getName().isIdentifier()) {
+    const auto *FD = dyn_cast_if_present<FunctionDecl>(TargetDecl);
+    if (FD && FD->getNameInfo().getName().isIdentifier()) {
+      StringRef FuncName = FD->getName();
+      const bool IsFloat32Type = FD->getReturnType()->isFloat32Type();
+      bool hasFPAccuracyFuncMap = hasAccuracyRequirement(FuncName);
+      bool hasFPAccuracyVal = !getLangOpts().FPAccuracyVal.empty();
+      bool isFp32SqrtFunction =
+          (FuncName == "sqrt" && !getLangOpts().OffloadFP32PrecSqrt &&
+           IsFloat32Type);
+      bool isFP32FdivFunction =
+          (FuncName == "fdiv" && !getLangOpts().OffloadFP32PrecDiv &&
+           IsFloat32Type);
+      if (hasFPAccuracyFuncMap || hasFPAccuracyVal || isFp32SqrtFunction ||
+          isFP32FdivFunction) {
         CI = MaybeEmitFPBuiltinofFD(IRFuncTy, IRCallArgs, CalleePtr,
                                     FD->getName(), FD->getBuiltinID());
         if (CI)

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -122,6 +122,13 @@ clang::ToConstrainedExceptMD(LangOptions::FPExceptionModeKind Kind) {
   }
 }
 
+bool CodeGenFunction::hasAccuracyRequirement(StringRef Name) {
+  if (!getLangOpts().FPAccuracyVal.empty())
+    return true;
+  auto FuncMapIt = getLangOpts().FPAccuracyFuncMap.find(Name.str());
+  return FuncMapIt != getLangOpts().FPAccuracyFuncMap.end();
+}
+
 void CodeGenFunction::SetFastMathFlags(FPOptions FPFeatures) {
   llvm::FastMathFlags FMF;
   FMF.setAllowReassoc(FPFeatures.getAllowFPReassociate());

clang/lib/CodeGen/CodeGenFunction.h

@@ -5213,6 +5213,8 @@ class CodeGenFunction : public CodeGenTypeCache {
   /// CodeGenOpts.
   void SetDivFPAccuracy(llvm::Value *Val);
 
+  bool hasAccuracyRequirement(StringRef Name);
+
   /// Set the codegen fast-math flags.
   void SetFastMathFlags(FPOptions FPFeatures);
 

clang/lib/Driver/ToolChains/Clang.cpp

@@ -2950,10 +2950,32 @@ RenderComplexRangeOption(LangOptions::ComplexRangeKind Range) {
   return ComplexRangeStr;
 }
 
+static void EmitAccuracyDiag(const Driver &D, const JobAction &JA,
+                             StringRef AccuracValStr, StringRef TargetPrecStr) {
+  if (JA.isDeviceOffloading(Action::OFK_SYCL)) {
+    D.Diag(clang::diag::
+               warn_acuracy_conflicts_with_explicit_offload_fp32_prec_option)
+        << AccuracValStr << TargetPrecStr;
+  }
+}
+
+static SmallVector<StringRef, 8> SplitFPAccuracyVal(StringRef Val) {
+  SmallVector<StringRef, 8> ValuesArr;
+  SmallVector<StringRef, 8> FuncsArr;
+  Val.split(ValuesArr, ":");
+  if (ValuesArr.size() > 1) {
+    StringRef x = ValuesArr[1];
+    x.split(FuncsArr, ",");
+  }
+  return FuncsArr;
+}
+
 static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
                                        bool OFastEnabled, const ArgList &Args,
                                        ArgStringList &CmdArgs,
-                                       const JobAction &JA) {
+                                       const JobAction &JA,
+                                       bool &NoOffloadFP32PrecDiv,
+                                       bool &NoOffloadFP32PrecSqrt) {
   // Handle various floating point optimization flags, mapping them to the
   // appropriate LLVM code generation flags. This is complicated by several
   // "umbrella" flags, so we do this by stepping through the flags incrementally
@@ -2998,6 +3020,7 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
   LangOptions::ComplexRangeKind Range = LangOptions::ComplexRangeKind::CX_None;
   std::string ComplexRangeStr = "";
   std::string GccRangeComplexOption = "";
+  bool IsDeviceOffloading = JA.isDeviceOffloading(Action::OFK_SYCL);
 
   // Lambda to set fast-math options. This is also used by -ffp-model=fast
   auto applyFastMath = [&]() {
@@ -3027,6 +3050,12 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
               : ComplexArithmeticStr(LangOptions::ComplexRangeKind::CX_Basic));
     Range = LangOptions::ComplexRangeKind::CX_Basic;
     SeenUnsafeMathModeOption = true;
+    if (IsDeviceOffloading) {
+      // when fp-model=fast is used the default precision for division and
+      // sqrt is not precise.
+      NoOffloadFP32PrecDiv = true;
+      NoOffloadFP32PrecSqrt = true;
+    }
   };
 
   // Lambda to consolidate common handling for fp-contract
@@ -3055,11 +3084,48 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     CmdArgs.push_back(A->getValue());
   }
 
+  auto addSPIRVArgs = [&](StringRef SPIRVArg) {
+    if (IsDeviceOffloading) {
+      if (!FPAccuracy.empty())
+        EmitAccuracyDiag(D, JA, FPAccuracy, SPIRVArg);
+      if (SPIRVArg == "-fno-offload-fp32-prec-div")
+        NoOffloadFP32PrecDiv = true;
+      else if (SPIRVArg == "-fno-offload-fp32-prec-sqrt")
+        NoOffloadFP32PrecSqrt = true;
+      else if (SPIRVArg == "-foffload-fp32-prec-sqrt")
+        NoOffloadFP32PrecSqrt = false;
+      else if (SPIRVArg == "-foffload-fp32-prec-div")
+        NoOffloadFP32PrecDiv = false;
+    }
+  };
+
+  auto parseFPAccOption = [&](StringRef Val, bool &NoOffloadFlag) {
+    SmallVector<StringRef, 8> FuncsArr = SplitFPAccuracyVal(Val);
+    for (const auto &V : FuncsArr) {
+      if (V == "fdiv")
+        NoOffloadFlag = false;
+      else if (V == "sqrt")
+        NoOffloadFlag = false;
+    }
+  };
+
   for (const Arg *A : Args) {
     switch (A->getOption().getID()) {
     // If this isn't an FP option skip the claim below
     default: continue;
 
+    case options::OPT_foffload_fp32_prec_div:
+      addSPIRVArgs("-foffload-fp32-prec-div");
+      break;
+    case options::OPT_foffload_fp32_prec_sqrt:
+      addSPIRVArgs("-foffload-fp32-prec-sqrt");
+      break;
+    case options::OPT_fno_offload_fp32_prec_div:
+      addSPIRVArgs("-fno-offload-fp32-prec-div");
+      break;
+    case options::OPT_fno_offload_fp32_prec_sqrt:
+      addSPIRVArgs("-fno-offload-fp32-prec-sqrt");
+      break;
     case options::OPT_fcx_limited_range:
       if (GccRangeComplexOption.empty()) {
         if (Range != LangOptions::ComplexRangeKind::CX_Basic)
@@ -3144,6 +3210,14 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     case options::OPT_ffp_accuracy_EQ: {
       StringRef Val = A->getValue();
       FPAccuracy = Val;
+      if (NoOffloadFP32PrecDiv) {
+        EmitAccuracyDiag(D, JA, FPAccuracy, "-fno-offload-fp32-prec-div");
+        parseFPAccOption(Val, NoOffloadFP32PrecDiv);
+      }
+      if (NoOffloadFP32PrecSqrt) {
+        EmitAccuracyDiag(D, JA, FPAccuracy, "-fno-offload-fp32-prec-sqrt");
+        parseFPAccOption(Val, NoOffloadFP32PrecSqrt);
+      }
       break;
     }
     case options::OPT_ffp_model_EQ: {
@@ -3557,6 +3631,12 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     CmdArgs.push_back("-fno-cx-limited-range");
   if (Args.hasArg(options::OPT_fno_cx_fortran_rules))
     CmdArgs.push_back("-fno-cx-fortran-rules");
+  if (IsDeviceOffloading) {
+    if (NoOffloadFP32PrecDiv)
+      CmdArgs.push_back("-fno-offload-fp32-prec-div");
+    if (NoOffloadFP32PrecSqrt)
+      CmdArgs.push_back("-fno-offload-fp32-prec-sqrt");
+  }
 }
 
 static void RenderAnalyzerOptions(const ArgList &Args, ArgStringList &CmdArgs,
@@ -5311,6 +5391,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
   const Driver &D = TC.getDriver();
   ArgStringList CmdArgs;
+  bool NoOffloadFP32PrecDiv = false;
+  bool NoOffloadFP32PrecSqrt = false;
 
   assert(Inputs.size() >= 1 && "Must have at least one input.");
   // CUDA/HIP compilation may have multiple inputs (source file + results of
@@ -6119,7 +6201,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                        options::OPT_fno_optimize_sibling_calls);
 
     RenderFloatingPointOptions(TC, D, isOptimizationLevelFast(Args), Args,
-                               CmdArgs, JA);
+                               CmdArgs, JA, NoOffloadFP32PrecDiv,
+                               NoOffloadFP32PrecSqrt);
 
     // Render ABI arguments
     switch (TC.getArch()) {
@@ -6593,7 +6676,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                    options::OPT_fno_protect_parens, false))
     CmdArgs.push_back("-fprotect-parens");
 
-  RenderFloatingPointOptions(TC, D, OFastEnabled, Args, CmdArgs, JA);
+  RenderFloatingPointOptions(TC, D, OFastEnabled, Args, CmdArgs, JA,
+                             NoOffloadFP32PrecDiv, NoOffloadFP32PrecSqrt);
 
   if (Arg *A = Args.getLastArg(options::OPT_fextend_args_EQ)) {
     const llvm::Triple::ArchType Arch = TC.getArch();
@@ -6644,8 +6728,18 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       FpAccuracyAttr += OptStr.str();
     }
   };
-  for (StringRef A : Args.getAllArgValues(options::OPT_ffp_accuracy_EQ))
-    RenderFPAccuracyOptions(A);
+  auto shouldAddFpAccuracyOption = [&](StringRef Val, StringRef Func) {
+    SmallVector<StringRef, 8> FuncsArr = SplitFPAccuracyVal(Val);
+    for (const auto &V : FuncsArr)
+      return (V == Func);
+    return false;
+  };
+
+  for (StringRef A : Args.getAllArgValues(options::OPT_ffp_accuracy_EQ)) {
+    if (!(NoOffloadFP32PrecDiv && shouldAddFpAccuracyOption(A, "fdiv")) &&
+        !(NoOffloadFP32PrecSqrt && shouldAddFpAccuracyOption(A, "sqrt")))
+      RenderFPAccuracyOptions(A);
+  }
   if (!FpAccuracyAttr.empty())
     CmdArgs.push_back(Args.MakeArgString(FpAccuracyAttr));
 
@@ -10603,8 +10697,22 @@ static void getTripleBasedSPIRVTransOpts(Compilation &C,
               ",+SPV_KHR_non_semantic_info"
               ",+SPV_KHR_cooperative_matrix"
               ",+SPV_EXT_shader_atomic_float16_add";
-  if (IsCPU)
+  auto hasNoOffloadFP32PrecOption = [](const llvm::opt::ArgList &TCArgs) {
+    return !TCArgs.hasFlag(options::OPT_foffload_fp32_prec_sqrt,
+                           options::OPT_fno_offload_fp32_prec_sqrt, false) &&
+           !TCArgs.hasFlag(options::OPT_foffload_fp32_prec_div,
+                           options::OPT_fno_offload_fp32_prec_div, false);
+  };
+  auto shouldUseOffloadFP32PrecOption = [](const llvm::opt::ArgList &TCArgs) {
+    return (TCArgs.hasFlag(options::OPT_fno_offload_fp32_prec_sqrt,
+                           options::OPT_foffload_fp32_prec_sqrt, false) ||
+            TCArgs.hasFlag(options::OPT_fno_offload_fp32_prec_div,
+                           options::OPT_foffload_fp32_prec_div, false));
+  };
+  if ((IsCPU && hasNoOffloadFP32PrecOption(TCArgs)) ||
+      shouldUseOffloadFP32PrecOption(TCArgs)) {
     ExtArg += ",+SPV_INTEL_fp_max_error";
+  }
 
   TranslatorArgs.push_back(TCArgs.MakeArgString(ExtArg));
 }