Bundle operands to specify denormal modes #136501
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Two new operands are now supported in the "fp.control" operand bundle:
* "denorm.in=xxx" - specifies the inpot denormal mode.
* "denorm.out=xxx" - specifies the output denormal mode.
Here xxx must be one of the following values:
* "ieee" - preserve denormals.
* "zero" - flush to zero preserving sign.
* "pzero" - flush to positive zero.
* "dyn" - mode is dynamically read from a control register.
These values align those permitted in the "denormal-fp-math" function
attribute.
spavloff
requested review from
arsenm,
nikic,
dtcxzyw,
andykaylor,
kpneal,
jcranmer-intel and
efriedma-quic
|
@llvm/pr-subscribers-llvm-ir @llvm/pr-subscribers-llvm-adt Author: Serge Pavlov (spavloff) ChangesTwo new operands are now supported in the "fp.control" operand bundle: Here xxx must be one of the following values: These values align those permitted in the "denormal-fp-math" function attribute. Patch is 23.41 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/136501.diff 8 Files Affected:
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 8252971aa8a58..954f0e96b46f6 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -3084,7 +3084,10 @@ floating-point control modes and the treatment of status bits respectively.
An operand bundle tagged with "fp.control" contains information about the
control modes used for the operation execution. Operands specified in this
-bundle represent particular options. Currently, only rounding mode is supported.
+bundle represent particular options. The following modes are supported:
+
+* rounding mode,
+* denormal behavior.
Rounding mode is represented by a metadata string value, which specifies the
the mode used for the operation evaluation. Possible values are:
@@ -3103,6 +3106,19 @@ rounding rounding mode is taken from the control register (dynamic rounding).
In the particular case of :ref:`default floating-point environment <floatenv>`,
the operation uses rounding to nearest, ties to even.
+Denormal behavior defines whether denormal values are flushed to zero during
+the call's execution. This behavior is specified separately for input and
+output values. Such specification is a string, which starts with
+"denorm.in=" or "denorm.out=" respectively. The remainder of the string should
+be one of the values:
+
+::
+
+ ``"ieee"`` - preserve denormals,
+ ``"zero"`` - flush to +0.0 or -0.0 depending on value sign,
+ ``"pzero"`` - flush to +0.0,
+ ``"dyn"`` - concrete mode is read from some register.
+
An operand bundle tagged with "fp.except" may be associated with operations
that can read or write floating-point exception flags. It contains a single
metadata string value, which can have one of the following values:
diff --git a/llvm/include/llvm/ADT/FloatingPointMode.h b/llvm/include/llvm/ADT/FloatingPointMode.h
index 639d931ef88fe..5fceccfd1d0bf 100644
--- a/llvm/include/llvm/ADT/FloatingPointMode.h
+++ b/llvm/include/llvm/ADT/FloatingPointMode.h
@@ -234,6 +234,39 @@ void DenormalMode::print(raw_ostream &OS) const {
OS << denormalModeKindName(Output) << ',' << denormalModeKindName(Input);
}
+/// If the specified string represents denormal mode as used in operand bundles,
+/// returns the corresponding mode.
+inline std::optional<DenormalMode::DenormalModeKind>
+parseDenormalKindFromOperandBundle(StringRef Str) {
+ if (Str == "ieee")
+ return DenormalMode::IEEE;
+ if (Str == "zero")
+ return DenormalMode::PreserveSign;
+ if (Str == "pzero")
+ return DenormalMode::PositiveZero;
+ if (Str == "dyn")
+ return DenormalMode::Dynamic;
+ return std::nullopt;
+}
+
+/// Converts the specified denormal mode into string suitable for use in an
+/// operand bundle.
+inline std::optional<StringRef>
+printDenormalForOperandBundle(DenormalMode::DenormalModeKind Mode) {
+ switch (Mode) {
+ case DenormalMode::IEEE:
+ return "ieee";
+ case DenormalMode::PreserveSign:
+ return "zero";
+ case DenormalMode::PositiveZero:
+ return "pzero";
+ case DenormalMode::Dynamic:
+ return "dyn";
+ default:
+ return std::nullopt;
+ }
+}
+
/// Floating-point class tests, supported by 'is_fpclass' intrinsic. Actual
/// test may be an OR combination of basic tests.
enum FPClassTest : unsigned {
diff --git a/llvm/include/llvm/IR/InstrTypes.h b/llvm/include/llvm/IR/InstrTypes.h
index 8425243e5efe9..8492c911ffc6a 100644
--- a/llvm/include/llvm/IR/InstrTypes.h
+++ b/llvm/include/llvm/IR/InstrTypes.h
@@ -1092,12 +1092,24 @@ template <typename InputTy> class OperandBundleDefT {
using OperandBundleDef = OperandBundleDefT<Value *>;
using ConstOperandBundleDef = OperandBundleDefT<const Value *>;
+std::optional<StringRef> getBundleOperandByPrefix(OperandBundleUse Bundle,
+ StringRef Prefix);
+void addOperandToBundleTag(LLVMContext &Ctx,
+ SmallVectorImpl<OperandBundleDef> &Bundles,
+ StringRef Tag, size_t PrefixSize, StringRef Val);
+
void addFPRoundingBundle(LLVMContext &Ctx,
SmallVectorImpl<OperandBundleDef> &Bundles,
RoundingMode Rounding);
void addFPExceptionBundle(LLVMContext &Ctx,
SmallVectorImpl<OperandBundleDef> &Bundles,
fp::ExceptionBehavior Except);
+void addFPInputDenormBundle(LLVMContext &Ctx,
+ SmallVectorImpl<OperandBundleDef> &Bundles,
+ DenormalMode::DenormalModeKind Mode);
+void addFPOutputDenormBundle(LLVMContext &Ctx,
+ SmallVectorImpl<OperandBundleDef> &Bundles,
+ DenormalMode::DenormalModeKind Mode);
//===----------------------------------------------------------------------===//
// CallBase Class
@@ -2171,6 +2183,15 @@ class CallBase : public Instruction {
/// Return exception behavior specified for this call.
fp::ExceptionBehavior getExceptionBehavior() const;
+ /// Return input denormal mode specified by operand bundles.
+ DenormalMode::DenormalModeKind getInputDenormMode() const;
+
+ /// Return output denormal mode specified by operand bundles.
+ DenormalMode::DenormalModeKind getOutputDenormMode() const;
+
+ /// Return input and output denormal modes specified by operand bundles.
+ DenormalMode getDenormMode() const;
+
/// Used to keep track of an operand bundle. See the main comment on
/// OperandBundleUser above.
struct BundleOpInfo {
diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index dc905ab03e861..602aa380fab1f 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -1354,6 +1354,11 @@ static ConstantFP *flushDenormalConstantFP(ConstantFP *CFP,
if (!APF.isDenormal())
return CFP;
+ if (auto *CB = dyn_cast<CallBase>(Inst)) {
+ auto Mode = IsOutput ? CB->getOutputDenormMode() : CB->getInputDenormMode();
+ return flushDenormalConstant(CFP->getType(), APF, Mode);
+ }
+
DenormalMode Mode = getInstrDenormalMode(Inst, CFP->getType());
return flushDenormalConstant(CFP->getType(), APF,
IsOutput ? Mode.Output : Mode.Input);
@@ -2976,12 +2981,20 @@ static Constant *ConstantFoldIntrinsicCall2(Intrinsic::ID IntrinsicID, Type *Ty,
}
if (const auto *Op1 = dyn_cast<ConstantFP>(Operands[0])) {
- const APFloat &Op1V = Op1->getValueAPF();
+ ConstantFP *Op1F =
+ flushDenormalConstantFP(const_cast<ConstantFP *>(Op1), Call, false);
+ if (!Op1F)
+ return nullptr;
+ const APFloat &Op1V = Op1F->getValueAPF();
if (const auto *Op2 = dyn_cast<ConstantFP>(Operands[1])) {
if (Op2->getType() != Op1->getType())
return nullptr;
- const APFloat &Op2V = Op2->getValueAPF();
+ ConstantFP *Op2F =
+ flushDenormalConstantFP(const_cast<ConstantFP *>(Op2), Call, false);
+ if (!Op2F)
+ return nullptr;
+ const APFloat &Op2V = Op2F->getValueAPF();
if (const auto *ConstrIntr =
dyn_cast_if_present<ConstrainedFPIntrinsic>(Call)) {
@@ -3011,8 +3024,11 @@ static Constant *ConstantFoldIntrinsicCall2(Intrinsic::ID IntrinsicID, Type *Ty,
return evaluateCompare(Op1V, Op2V, ConstrIntr);
}
if (mayFoldConstrained(const_cast<ConstrainedFPIntrinsic *>(ConstrIntr),
- St))
- return ConstantFP::get(Ty->getContext(), Res);
+ St)) {
+ auto DenormOut = Call->getOutputDenormMode();
+ DenormalMode::DenormalModeKind Mode = DenormOut;
+ return flushDenormalConstant(Op2->getType(), Res, Mode);
+ }
return nullptr;
}
diff --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index 1073c2939a8a3..da766473f5fff 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -628,13 +628,17 @@ bool CallBase::hasClobberingOperandBundles() const {
RoundingMode CallBase::getRoundingMode() const {
// Try reading rounding mode from FP bundle.
std::optional<RoundingMode> RM;
- if (auto RoundingBundle = getOperandBundle(LLVMContext::OB_fp_control)) {
- Value *V = RoundingBundle->Inputs.front();
- Metadata *MD = cast<MetadataAsValue>(V)->getMetadata();
- RM = convertBundleToRoundingMode(cast<MDString>(MD)->getString());
+ if (auto ControlBundle = getOperandBundle(LLVMContext::OB_fp_control)) {
+ for (auto &U : ControlBundle->Inputs) {
+ Value *V = U.get();
+ if (auto *MDV = dyn_cast<MetadataAsValue>(V)) {
+ Metadata *MD = MDV->getMetadata();
+ if (auto *MDS = dyn_cast<MDString>(MD))
+ if (auto RM = convertBundleToRoundingMode(MDS->getString()))
+ return *RM;
+ }
+ }
}
- if (RM)
- return *RM;
// If this is a constrained intrinsic, get rounding mode from its metadata
// arguments.
@@ -678,6 +682,71 @@ fp::ExceptionBehavior CallBase::getExceptionBehavior() const {
return fp::ebIgnore;
}
+DenormalMode::DenormalModeKind CallBase::getInputDenormMode() const {
+ if (auto InDenormBundle = getOperandBundle(LLVMContext::OB_fp_control)) {
+ auto DenormOperand =
+ getBundleOperandByPrefix(*InDenormBundle, "denorm.in=");
+ if (DenormOperand) {
+ if (auto Mode = parseDenormalKindFromOperandBundle(*DenormOperand))
+ return *Mode;
+ } else {
+ return DenormalMode::IEEE;
+ }
+ }
+
+ if (!getParent())
+ return DenormalMode::IEEE;
+ const Function *F = getFunction();
+ if (!F)
+ return DenormalMode::IEEE;
+
+ Type *Ty = nullptr;
+ for (auto &A : args())
+ if (auto *T = A.get()->getType(); T->isFPOrFPVectorTy()) {
+ Ty = T;
+ break;
+ }
+ assert(Ty && "Some input argument must be of floating-point type");
+
+ Ty = Ty->getScalarType();
+ return F->getDenormalMode(Ty->getFltSemantics()).Input;
+}
+
+DenormalMode::DenormalModeKind CallBase::getOutputDenormMode() const {
+ if (auto InDenormBundle = getOperandBundle(LLVMContext::OB_fp_control)) {
+ auto DenormOperand =
+ getBundleOperandByPrefix(*InDenormBundle, "denorm.out=");
+ if (DenormOperand) {
+ if (auto Mode = parseDenormalKindFromOperandBundle(*DenormOperand))
+ return *Mode;
+ } else {
+ return DenormalMode::IEEE;
+ }
+ }
+
+ if (!getParent())
+ return DenormalMode::IEEE;
+ const Function *F = getFunction();
+ if (!F)
+ return DenormalMode::IEEE;
+
+ Type *Ty = getType();
+ assert(Ty->isFPOrFPVectorTy() && "Unexpected output type");
+
+ Ty = Ty->getScalarType();
+ return F->getDenormalMode(Ty->getFltSemantics()).Output;
+}
+
+DenormalMode CallBase::getDenormMode() const {
+ auto InputMode = getInputDenormMode();
+ auto OutputMode = getOutputDenormMode();
+ if (!InputMode)
+ InputMode = DenormalMode::IEEE;
+ if (!OutputMode)
+ OutputMode = DenormalMode::IEEE;
+ return DenormalMode(OutputMode, InputMode);
+}
+
MemoryEffects CallBase::getFloatingPointMemoryEffects() const {
if (Intrinsic::ID IntrID = getIntrinsicID())
if (const BasicBlock *BB = getParent())
@@ -794,6 +863,69 @@ bool CallBase::hasArgumentWithAdditionalReturnCaptureComponents() const {
return false;
}
+std::optional<StringRef> llvm::getBundleOperandByPrefix(OperandBundleUse Bundle,
+ StringRef Prefix) {
+ for (const auto &Item : Bundle.Inputs) {
+ Metadata *MD = cast<MetadataAsValue>(Item.get())->getMetadata();
+ if (const auto *MDS = dyn_cast<MDString>(MD)) {
+ StringRef Str = MDS->getString();
+ if (Str.consume_front(Prefix))
+ return Str;
+ }
+ }
+ return std::nullopt;
+}
+
+void llvm::addOperandToBundleTag(LLVMContext &Ctx,
+ SmallVectorImpl<OperandBundleDef> &Bundles,
+ StringRef Tag, size_t PrefixSize,
+ StringRef Val) {
+ assert(PrefixSize > 0 && "Unexpected prefix size");
+ assert(PrefixSize < Val.size() && "Invalid prefix size");
+ StringRef Prefix = Val.take_front(PrefixSize);
+
+ // Find a bundle with the specified tag.
+ OperandBundleDef *Bundle = nullptr;
+ for (OperandBundleDef &OB : Bundles) {
+ if (OB.getTag() == Tag) {
+ Bundle = &OB;
+ break;
+ }
+ }
+
+ // If no such bundle are found, create new one with the single value.
+ if (!Bundle) {
+ auto *MStr = MDString::get(Ctx, Val);
+ auto *MD = MetadataAsValue::get(Ctx, MStr);
+ SmallVector<Value *, 1> BundleValues(1, MD);
+ Bundles.emplace_back(Tag.str(), BundleValues);
+ return;
+ }
+
+ // If the bundle is found, search its values for those started with the given
+ // prefix.
+ SmallVector<Value *, 4> Values(Bundle->inputs());
+ for (auto i = Values.begin(), e = Values.end(); i != e; ++i) {
+ if (auto *MV = dyn_cast<MetadataAsValue>(*i)) {
+ if (auto *MD = dyn_cast<MDString>(MV->getMetadata())) {
+ StringRef Str = MD->getString();
+ if (Str == Val)
+ // Already in the values.
+ return;
+ if (Str.starts_with(Prefix)) {
+ Values.erase(i);
+ break;
+ }
+ }
+ }
+ }
+
+ auto *ValMD = MDString::get(Ctx, Val);
+ auto *MD = MetadataAsValue::get(Ctx, ValMD);
+ Values.push_back(MD);
+ Bundles.emplace_back("fp.control", Values);
+}
+
void llvm::addFPRoundingBundle(LLVMContext &Ctx,
SmallVectorImpl<OperandBundleDef> &Bundles,
RoundingMode Rounding) {
@@ -814,6 +946,30 @@ void llvm::addFPExceptionBundle(LLVMContext &Ctx,
Bundles.emplace_back("fp.except", EB);
}
+void llvm::addFPInputDenormBundle(LLVMContext &Ctx,
+ SmallVectorImpl<OperandBundleDef> &Bundles,
+ DenormalMode::DenormalModeKind Mode) {
+ std::optional<StringRef> DenormValue = printDenormalForOperandBundle(Mode);
+ if (!DenormValue)
+ return;
+ std::string Prefix = "denorm.in=";
+ std::string DenormItem = Prefix + DenormValue->str();
+
+ addOperandToBundleTag(Ctx, Bundles, "fp.control", Prefix.size(), DenormItem);
+}
+
+void llvm::addFPOutputDenormBundle(LLVMContext &Ctx,
+ SmallVectorImpl<OperandBundleDef> &Bundles,
+ DenormalMode::DenormalModeKind Mode) {
+ std::optional<StringRef> DenormValue = printDenormalForOperandBundle(Mode);
+ if (!DenormValue)
+ return;
+ std::string Prefix = "denorm.out=";
+ std::string DenormItem = Prefix + DenormValue->str();
+
+ addOperandToBundleTag(Ctx, Bundles, "fp.control", Prefix.size(), DenormItem);
+}
+
//===----------------------------------------------------------------------===//
// CallInst Implementation
//===----------------------------------------------------------------------===//
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 6b7644fef9e71..bb40c4b7b7b83 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -3833,6 +3833,8 @@ void Verifier::visitCallBase(CallBase &Call) {
Check(!FoundFpeControlBundle, "Multiple \"fp.control\" operand bundles",
Call);
bool FoundRoundingMode = false;
+ bool FoundInDenormalMode = false;
+ bool FoundOutDenormalMode = false;
for (auto &U : BU.Inputs) {
Value *V = U.get();
Check(isa<MetadataAsValue>(V),
@@ -3847,6 +3849,18 @@ void Verifier::visitCallBase(CallBase &Call) {
Check(!FoundRoundingMode, "Rounding mode is specified more that once",
Call);
FoundRoundingMode = true;
+ } else if (Item.consume_front("denorm.in=")) {
+ Check(!FoundInDenormalMode,
+ "Input denormal mode is specified more that once", Call);
+ FoundInDenormalMode = true;
+ Check(parseDenormalKindFromOperandBundle(Item),
+ "Invalid input denormal mode", Call);
+ } else if (Item.consume_front("denorm.out=")) {
+ Check(!FoundOutDenormalMode,
+ "Output denormal mode is specified more that once", Call);
+ FoundOutDenormalMode = true;
+ Check(parseDenormalKindFromOperandBundle(Item),
+ "Invalid output denormal mode", Call);
} else {
CheckFailed("Unrecognized value in \"fp.control\" bundle operand",
Call);
diff --git a/llvm/test/Transforms/InstSimplify/constant-fold-fp-denormal-strict.ll b/llvm/test/Transforms/InstSimplify/constant-fold-fp-denormal-strict.ll
new file mode 100644
index 0000000000000..c9886928ce4a4
--- /dev/null
+++ b/llvm/test/Transforms/InstSimplify/constant-fold-fp-denormal-strict.ll
@@ -0,0 +1,91 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -passes=instsimplify < %s | FileCheck %s
+
+; 0xB810000000000000 = -0x1.0p-126
+; 0x3800000000000000 = 0x1.0p-127 denormal
+
+define float @test_float_fadd_ieee_strict() #0 {
+; CHECK-LABEL: define float @test_float_fadd_ieee_strict(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT: ret float 0xB800000000000000
+;
+ %result = call float @llvm.experimental.constrained.fadd.f32(float 0xB810000000000000, float 0x3800000000000000, metadata !"round.towardzero", metadata !"fpexcept.ignore")
+ ret float %result
+}
+
+define float @test_float_fadd_strict_ieee() #0 {
+; CHECK-LABEL: define float @test_float_fadd_strict_ieee(
+; CHECK-SAME: ) #[[ATTR0]] {
+; CHECK-NEXT: ret float 0xB800000000000000
+;
+ %result = call float @llvm.experimental.constrained.fadd.f32(float 0xB810000000000000, float 0x3800000000000000, metadata !"round.towardzero", metadata !"fpexcept.ignore") [ "fp.control" (metadata !"denorm.in=ieee", metadata !"denorm.out=ieee") ]
+ ret float %result
+}
+
+define float @test_float_fadd_strict_inzero() #0 {
+; CHECK-LABEL: define float @test_float_fadd_strict_inzero(
+; CHECK-SAME: ) #[[ATTR0]] {
+; CHECK-NEXT: ret float 0xB810000000000000
+;
+ %result = call float @llvm.experimental.constrained.fadd.f32(float 0xB810000000000000, float 0x3800000000000000, metadata !"round.towardzero", metadata !"fpexcept.ignore") [ "fp.control" (metadata !"denorm.in=zero", metadata !"denorm.out=ieee") ]
+ ret float %result
+}
+
+define float @test_float_fadd_strict_inpzero() #0 {
+; CHECK-LABEL: define float @test_float_fadd_strict_inpzero(
+; CHECK-SAME: ) #[[ATTR0]] {
+; CHECK-NEXT: ret float 0xB810000000000000
+;
+ %result = call float @llvm.experimental.constrained.fadd.f32(float 0xB810000000000000, float 0x3800000000000000, metadata !"round.towardzero", metadata !"fpexcept.ignore") [ "fp.control" (metadata !"denorm.in=pzero", metadata !"denorm.out=ieee") ]
+ ret float %result
+}
+
+define float @test_float_fadd_strict_indyn() #0 {
+; CHECK-LABEL: define float @test_float_fadd_strict_indyn(
+; CHECK-SAME: ) #[[ATTR0]] {
+; CHECK-NEXT: [[RESULT:%.*]] = call float @llvm.experimental.constrained.fadd.f32(float 0xB810000000000000, float 0x3800000000000000, metadata !"round.towardzero", metadata !"fpexcept.ignore") [ "fp.control"(metadata !"denorm.in=dyn", metadata !"denorm.out=ieee") ]
+; CHECK-NEXT: ret float [[RESULT]]
+;
+ %result = call float @llvm.experimental.constrained.fadd.f32(float 0xB810000000000000, float 0x3800000000000000, metadata !"round.towardzero", metadata !"fpexcept.ignore") [ "fp.control" (metadata !"denorm.in=dyn", metadata !"denorm.out=ieee") ]
+ ret float %result
+}
+
+define float @test_float_fadd_strict_ieee_outzero() #0 {
+; CHECK-LABEL: define float @test_float_fadd_strict_ieee_outzero(
+; CHECK-SAME: ) #[[ATTR0]] {
+; CHECK-NEXT: ret float -0.000000e+00
+;
+ %result = call float @llvm.experimental.constrained.fadd.f32(float 0xB810000000000000, float 0x3800000000000000, metadata !"round.towardzero", metadata !"fpexcept.ignore") [ "fp.control" (metadata !"denorm.in=ieee", metadata !"denorm.out=zero") ]
+ ret float %result
+}
+
+define float @test_float_fadd_strict_ieee_outpzero() #0 {
+; CHECK-LABEL: define float @test_float_fadd_strict_ieee_outpzero(
+; CHECK-SAME: ) #[[ATTR0]] {
+; CHECK-NEXT: ret float 0.000000e+00
+;
+ %result = call float @llvm.experimental.constrained.fadd.f32(float 0xB810000000000000, float 0x3800000000000000, metadata !"round.towardzero", metadata !"fpexcept.ignore") [ "fp.control" (metadata !"denorm.in=iee...
[truncated]
|
You can test this locally with the following command:git-clang-format --diff HEAD~1 HEAD --extensions cpp,h -- llvm/include/llvm/ADT/FloatingPointMode.h llvm/include/llvm/IR/InstrTypes.h llvm/lib/Analysis/ConstantFolding.cpp llvm/lib/IR/Instructions.cpp llvm/lib/IR/Verifier.cppView the diff from clang-format here.diff --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index 8a5c41051..bf02bd26d 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -891,7 +891,7 @@ bool CallBase::hasArgumentWithAdditionalReturnCaptureComponents() const {
}
std::optional<StringRef> llvm::getBundleOperandByPrefix(OperandBundleUse Bundle,
- StringRef Prefix) {
+ StringRef Prefix) {
for (const auto &Item : Bundle.Inputs) {
Metadata *MD = cast<MetadataAsValue>(Item.get())->getMetadata();
if (const auto *MDS = dyn_cast<MDString>(MD)) {
@@ -904,9 +904,9 @@ std::optional<StringRef> llvm::getBundleOperandByPrefix(OperandBundleUse Bundle,
}
void llvm::addOperandToBundleTag(LLVMContext &Ctx,
- SmallVectorImpl<OperandBundleDef> &Bundles,
- StringRef Tag, size_t PrefixSize,
- StringRef Val) {
+ SmallVectorImpl<OperandBundleDef> &Bundles,
+ StringRef Tag, size_t PrefixSize,
+ StringRef Val) {
assert(PrefixSize > 0 && "Unexpected prefix size");
assert(PrefixSize < Val.size() && "Invalid prefix size");
StringRef Prefix = Val.take_front(PrefixSize);
|
arsenm
reviewed
Apr 21, 2025
llvm/lib/IR/Instructions.cpp
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| for (auto &A : args()) | ||
| if (auto *T = A.get()->getType(); T->isFPOrFPVectorTy()) { | ||
| Ty = T; | ||
| break; | ||
| } | ||
| assert(Ty && "Some input argument must be of floating-point type"); |
There was a problem hiding this comment.
This probably can't be an assert
What happens if there are multiple input floating point type arguments, and each one has a differently controllable denormal mode?
For example, AMDGPU has some instructions with mixed half and float inputs, but those read from different FP mode controls (I haven't actually checked the right input mode bits are respected in these cases).
I'd probably just stop trying to report the mode if there are multiple input types
There was a problem hiding this comment.
It means that we have more than one denormal mode in a single instruction, so they need to be distinguish them somehow, by type in your case.
Is it possible that an instruction has multiple output denormal modes?
What about rounding mode? It it possible that evaluation of an instruction requires two different rounding modes?
There was a problem hiding this comment.
Introduced "denorm.f32.in=" and "denorm.f32.out=" bundle operands.
llvm/lib/IR/Instructions.cpp
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| if (!getParent()) | ||
| return DenormalMode::IEEE; | ||
| const Function *F = getFunction(); | ||
| if (!F) | ||
| return DenormalMode::IEEE; |
There was a problem hiding this comment.
I don't think this low level query should try to get creative and inspect the calling context function. It should stick to just parsing the bundle
There was a problem hiding this comment.
Removed this search.
- introduced bundle operands for 32-bit vslues, - simplified demormal mode search, - updated documentation.
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Two new operands are now supported in the "fp.control" operand bundle:
Here xxx must be one of the following values:
These values align those permitted in the "denormal-fp-math" function attribute.