[llvm] [SPIR-V] Support SPV_INTEL_fp_max_error extension for `!fpmath` metadata (PR #130619)
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llvm-commits at lists.llvm.org
Mon Mar 10 07:45:59 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-spir-v
Author: Viktoria Maximova (vmaksimo)
<details>
<summary>Changes</summary>
Specification:
https://github.khronos.org/SPIRV-Registry/extensions/INTEL/SPV_INTEL_fp_max_error.html
---
Full diff: https://github.com/llvm/llvm-project/pull/130619.diff
8 Files Affected:
- (modified) llvm/docs/SPIRVUsage.rst (+6)
- (modified) llvm/include/llvm/IR/IntrinsicsSPIRV.td (+2)
- (modified) llvm/lib/Target/SPIRV/SPIRVCommandLine.cpp (+3-1)
- (modified) llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp (+13)
- (modified) llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp (+3)
- (modified) llvm/lib/Target/SPIRV/SPIRVPreLegalizer.cpp (+21-1)
- (modified) llvm/lib/Target/SPIRV/SPIRVSymbolicOperands.td (+3)
- (added) llvm/test/CodeGen/SPIRV/extensions/SPV_INTEL_fp_max_error/IntelFPMaxErrorFPMath.ll (+35)
``````````diff
diff --git a/llvm/docs/SPIRVUsage.rst b/llvm/docs/SPIRVUsage.rst
index 6a27e0efaec7f..ee5937f208825 100644
--- a/llvm/docs/SPIRVUsage.rst
+++ b/llvm/docs/SPIRVUsage.rst
@@ -207,6 +207,8 @@ list of supported SPIR-V extensions, sorted alphabetically by their extension na
- Allows support for additional group operations within uniform control flow.
* - ``SPV_KHR_non_semantic_info``
- Adds the ability to declare extended instruction sets that have no semantic impact and can be safely removed from a module.
+ * - ``SPV_INTEL_fp_max_error``
+ - Adds the ability to specify the maximum error for floating-point operations.
To enable multiple extensions, list them separated by comma. For example, to enable support for atomic operations on floating-point numbers and arbitrary precision integers, use:
@@ -307,6 +309,10 @@ SPIR-V backend, along with their descriptions and argument details.
- None
- `[Type, 32-bit Integer, Metadata]`
- Assigns one of two memory aliasing decorations (specified by the second argument) to instructions using original aliasing metadata node. Not emitted directly but used to support SPIR-V representation in LLVM IR.
+ * - `int_spv_assign_fpmaxerror_decoration`
+ - None
+ - `[Type, Metadata]`
+ - Assigns the maximum error decoration to floating-point instructions using the original metadata node. Not emitted directly but used to support SPIR-V representation in LLVM IR.
* - `int_spv_track_constant`
- Type
- `[Type, Metadata]`
diff --git a/llvm/include/llvm/IR/IntrinsicsSPIRV.td b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
index 7012ef3534c68..df3e137c80980 100644
--- a/llvm/include/llvm/IR/IntrinsicsSPIRV.td
+++ b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
@@ -141,4 +141,6 @@ let TargetPrefix = "spv" in {
// Memory aliasing intrinsics
def int_spv_assign_aliasing_decoration : Intrinsic<[], [llvm_any_ty, llvm_i32_ty, llvm_metadata_ty], [ImmArg<ArgIndex<1>>]>;
+ // FPMaxErrorDecorationINTEL
+ def int_spv_assign_fpmaxerror_decoration: Intrinsic<[], [llvm_any_ty, llvm_metadata_ty]>;
}
diff --git a/llvm/lib/Target/SPIRV/SPIRVCommandLine.cpp b/llvm/lib/Target/SPIRV/SPIRVCommandLine.cpp
index 8d1714932c3c6..37119bf01545c 100644
--- a/llvm/lib/Target/SPIRV/SPIRVCommandLine.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVCommandLine.cpp
@@ -90,7 +90,9 @@ static const std::map<std::string, SPIRV::Extension::Extension, std::less<>>
{"SPV_KHR_non_semantic_info",
SPIRV::Extension::Extension::SPV_KHR_non_semantic_info},
{"SPV_INTEL_long_composites",
- SPIRV::Extension::Extension::SPV_INTEL_long_composites}};
+ SPIRV::Extension::Extension::SPV_INTEL_long_composites},
+ {"SPV_INTEL_fp_max_error",
+ SPIRV::Extension::Extension::SPV_INTEL_fp_max_error}};
bool SPIRVExtensionsParser::parse(cl::Option &O, llvm::StringRef ArgName,
llvm::StringRef ArgValue,
diff --git a/llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp b/llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp
index 751ea5ab2dc47..00acb6aa19c9c 100644
--- a/llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp
@@ -2016,6 +2016,19 @@ void SPIRVEmitIntrinsics::insertSpirvDecorations(Instruction *I,
processMemAliasingDecoration(LLVMContext::MD_alias_scope);
processMemAliasingDecoration(LLVMContext::MD_noalias);
}
+ // MD_fpmath
+ if (MDNode *MD = I->getMetadata("fpmath")) {
+ const SPIRVSubtarget *STI = TM->getSubtargetImpl(*I->getFunction());
+ bool AllowFPMaxError =
+ STI->canUseExtension(SPIRV::Extension::SPV_INTEL_fp_max_error);
+ if (!AllowFPMaxError)
+ return;
+
+ setInsertPointAfterDef(B, I);
+ B.CreateIntrinsic(Intrinsic::spv_assign_fpmaxerror_decoration,
+ {I->getType()},
+ {I, MetadataAsValue::get(I->getContext(), MD)});
+ }
}
void SPIRVEmitIntrinsics::processInstrAfterVisit(Instruction *I,
diff --git a/llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp b/llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp
index e0b348f0bba10..63894acacbc73 100644
--- a/llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp
@@ -888,6 +888,9 @@ static void addOpDecorateReqs(const MachineInstr &MI, unsigned DecIndex,
SPIRV::Extension::SPV_INTEL_global_variable_fpga_decorations);
} else if (Dec == SPIRV::Decoration::NonUniformEXT) {
Reqs.addRequirements(SPIRV::Capability::ShaderNonUniformEXT);
+ } else if (Dec == SPIRV::Decoration::FPMaxErrorDecorationINTEL) {
+ Reqs.addRequirements(SPIRV::Capability::FPMaxErrorINTEL);
+ Reqs.addExtension(SPIRV::Extension::SPV_INTEL_fp_max_error);
}
}
diff --git a/llvm/lib/Target/SPIRV/SPIRVPreLegalizer.cpp b/llvm/lib/Target/SPIRV/SPIRVPreLegalizer.cpp
index baacd58b28028..4904506f25a08 100644
--- a/llvm/lib/Target/SPIRV/SPIRVPreLegalizer.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVPreLegalizer.cpp
@@ -819,18 +819,38 @@ static void insertInlineAsm(MachineFunction &MF, SPIRVGlobalRegistry *GR,
insertInlineAsmProcess(MF, GR, ST, MIRBuilder, ToProcess);
}
+static uint32_t convertFloatToSPIRVWord(float F) {
+ union {
+ float F;
+ uint32_t Spir;
+ } FPMaxError;
+ FPMaxError.F = F;
+ return FPMaxError.Spir;
+}
+
static void insertSpirvDecorations(MachineFunction &MF, SPIRVGlobalRegistry *GR,
MachineIRBuilder MIB) {
SmallVector<MachineInstr *, 10> ToErase;
for (MachineBasicBlock &MBB : MF) {
for (MachineInstr &MI : MBB) {
if (!isSpvIntrinsic(MI, Intrinsic::spv_assign_decoration) &&
- !isSpvIntrinsic(MI, Intrinsic::spv_assign_aliasing_decoration))
+ !isSpvIntrinsic(MI, Intrinsic::spv_assign_aliasing_decoration) &&
+ !isSpvIntrinsic(MI, Intrinsic::spv_assign_fpmaxerror_decoration))
continue;
MIB.setInsertPt(*MI.getParent(), MI.getNextNode());
if (isSpvIntrinsic(MI, Intrinsic::spv_assign_decoration)) {
buildOpSpirvDecorations(MI.getOperand(1).getReg(), MIB,
MI.getOperand(2).getMetadata());
+ } else if (isSpvIntrinsic(MI,
+ Intrinsic::spv_assign_fpmaxerror_decoration)) {
+ ConstantFP *OpV = mdconst::dyn_extract<ConstantFP>(
+ MI.getOperand(2).getMetadata()->getOperand(0));
+ uint32_t OpValue =
+ convertFloatToSPIRVWord(OpV->getValueAPF().convertToFloat());
+
+ buildOpDecorate(MI.getOperand(1).getReg(), MIB,
+ SPIRV::Decoration::FPMaxErrorDecorationINTEL,
+ {OpValue});
} else {
GR->buildMemAliasingOpDecorate(MI.getOperand(1).getReg(), MIB,
MI.getOperand(2).getImm(),
diff --git a/llvm/lib/Target/SPIRV/SPIRVSymbolicOperands.td b/llvm/lib/Target/SPIRV/SPIRVSymbolicOperands.td
index a871518e2094c..caee778eddbc4 100644
--- a/llvm/lib/Target/SPIRV/SPIRVSymbolicOperands.td
+++ b/llvm/lib/Target/SPIRV/SPIRVSymbolicOperands.td
@@ -312,6 +312,7 @@ defm SPV_INTEL_float_controls2 : ExtensionOperand<115>;
defm SPV_INTEL_bindless_images : ExtensionOperand<116>;
defm SPV_INTEL_long_composites : ExtensionOperand<117>;
defm SPV_INTEL_memory_access_aliasing : ExtensionOperand<118>;
+defm SPV_INTEL_fp_max_error : ExtensionOperand<119>;
//===----------------------------------------------------------------------===//
// Multiclass used to define Capabilities enum values and at the same time
@@ -511,6 +512,7 @@ defm FunctionFloatControlINTEL : CapabilityOperand<5821, 0, 0, [SPV_INTEL_float_
defm LongCompositesINTEL : CapabilityOperand<6089, 0, 0, [SPV_INTEL_long_composites], []>;
defm BindlessImagesINTEL : CapabilityOperand<6528, 0, 0, [SPV_INTEL_bindless_images], []>;
defm MemoryAccessAliasingINTEL : CapabilityOperand<5910, 0, 0, [SPV_INTEL_memory_access_aliasing], []>;
+defm FPMaxErrorINTEL : CapabilityOperand<6169, 0, 0, [SPV_INTEL_fp_max_error], []>;
//===----------------------------------------------------------------------===//
// Multiclass used to define SourceLanguage enum values and at the same time
@@ -1261,6 +1263,7 @@ defm FunctionDenormModeINTEL : DecorationOperand<5823, 0, 0, [], [FunctionFloatC
defm FunctionFloatingPointModeINTEL : DecorationOperand<6080, 0, 0, [], [FunctionFloatControlINTEL]>;
defm AliasScopeINTEL : DecorationOperand<5914, 0, 0, [], [MemoryAccessAliasingINTEL]>;
defm NoAliasINTEL : DecorationOperand<5915, 0, 0, [], [MemoryAccessAliasingINTEL]>;
+defm FPMaxErrorDecorationINTEL : DecorationOperand<6170, 0, 0, [], [FPMaxErrorINTEL]>;
//===----------------------------------------------------------------------===//
// Multiclass used to define BuiltIn enum values and at the same time
diff --git a/llvm/test/CodeGen/SPIRV/extensions/SPV_INTEL_fp_max_error/IntelFPMaxErrorFPMath.ll b/llvm/test/CodeGen/SPIRV/extensions/SPV_INTEL_fp_max_error/IntelFPMaxErrorFPMath.ll
new file mode 100644
index 0000000000000..66070181968e2
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/extensions/SPV_INTEL_fp_max_error/IntelFPMaxErrorFPMath.ll
@@ -0,0 +1,35 @@
+; Confirm that we handle fpmath metadata correctly
+; This is a copy of https://github.com/KhronosGroup/SPIRV-LLVM-Translator/blob/main/test/extensions/INTEL/SPV_INTEL_fp_max_error/IntelFPMaxErrorFPMath.ll
+
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv32-unknown-unknown --spirv-ext=+SPV_INTEL_fp_max_error %s -o %t.spt
+; RUN: FileCheck %s --input-file=%t.spt
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv32-unknown-unknown --spirv-ext=+SPV_INTEL_fp_max_error %s -o - -filetype=obj | spirv-val %}
+
+; CHECK: OpCapability FPMaxErrorINTEL
+; CHECK: OpExtension "SPV_INTEL_fp_max_error"
+
+; CHECK: OpName %[[#CalleeName:]] "callee"
+; CHECK: OpName %[[#F3:]] "f3"
+; CHECK: OpDecorate %[[#F3]] FPMaxErrorDecorationINTEL 1075838976
+; CHECK: OpDecorate %[[#Callee:]] FPMaxErrorDecorationINTEL 1065353216
+
+; CHECK: %[[#FloatTy:]] = OpTypeFloat 32
+; CHECK: %[[#Callee]] = OpFunctionCall %[[#FloatTy]] %[[#CalleeName]]
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-n8:16:32:64"
+target triple = "spir64-unknown-unknown"
+
+define float @callee(float %f1, float %f2) {
+entry:
+ret float %f1
+}
+
+define void @test_fp_max_error_decoration(float %f1, float %f2) {
+entry:
+%f3 = fdiv float %f1, %f2, !fpmath !0
+call float @callee(float %f1, float %f2), !fpmath !1
+ret void
+}
+
+!0 = !{float 2.500000e+00}
+!1 = !{float 1.000000e+00}
``````````
</details>
https://github.com/llvm/llvm-project/pull/130619
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