https://github.com/mcinally created
https://github.com/llvm/llvm-project/pull/141380
This patch adds support for the -mprefer-vector-width=<value> command line
option. The parsing of this options is equivalent to Clang's and it is
implemented by setting the "prefer-vector-width" function attribute.
>From 05221439896aabdcadf79d15ae6875dc34f10edd Mon Sep 17 00:00:00 2001
From: Cameron McInally <cmcina...@nvidia.com>
Date: Sat, 24 May 2025 13:35:13 -0700
Subject: [PATCH] [flang] Add support for -mprefer-vector-width=<value>
This patch adds support for the -mprefer-vector-width=<value>
command line option. The parsing of this options is equivalent
to Clang's and it is implemented by setting the
"prefer-vector-width" function attribute.
---
clang/include/clang/Driver/Options.td | 2 +-
flang/include/flang/Frontend/CodeGenOptions.h | 3 +++
.../include/flang/Optimizer/Transforms/Passes.td | 4 ++++
flang/include/flang/Tools/CrossToolHelpers.h | 3 +++
flang/lib/Frontend/CompilerInvocation.cpp | 14 ++++++++++++++
flang/lib/Frontend/FrontendActions.cpp | 2 ++
flang/lib/Optimizer/Passes/Pipelines.cpp | 2 +-
flang/lib/Optimizer/Transforms/FunctionAttr.cpp | 5 +++++
flang/test/Driver/prefer-vector-width.f90 | 16 ++++++++++++++++
mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td | 1 +
mlir/lib/Target/LLVMIR/ModuleImport.cpp | 4 ++++
mlir/lib/Target/LLVMIR/ModuleTranslation.cpp | 3 +++
12 files changed, 57 insertions(+), 2 deletions(-)
create mode 100644 flang/test/Driver/prefer-vector-width.f90
diff --git a/clang/include/clang/Driver/Options.td
b/clang/include/clang/Driver/Options.td
index 22261621df092..b0b642796010b 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5480,7 +5480,7 @@ def mrecip_EQ : CommaJoined<["-"], "mrecip=">,
Group<m_Group>,
"<value> = ( ['!'] ['vec-'] ('rcp'|'sqrt') [('h'|'s'|'d')] [':'<n>]
) | 'all' | 'default' | 'none'">,
MarshallingInfoStringVector<CodeGenOpts<"Reciprocals">>;
def mprefer_vector_width_EQ : Joined<["-"], "mprefer-vector-width=">,
Group<m_Group>,
- Visibility<[ClangOption, CC1Option]>,
+ Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
HelpText<"Specifies preferred vector width for auto-vectorization. Defaults
to 'none' which allows target specific decisions.">,
MarshallingInfoString<CodeGenOpts<"PreferVectorWidth">>;
def mstack_protector_guard_EQ : Joined<["-"], "mstack-protector-guard=">,
Group<m_Group>,
diff --git a/flang/include/flang/Frontend/CodeGenOptions.h
b/flang/include/flang/Frontend/CodeGenOptions.h
index 2b4e823b3fef4..61e56e51c4bbb 100644
--- a/flang/include/flang/Frontend/CodeGenOptions.h
+++ b/flang/include/flang/Frontend/CodeGenOptions.h
@@ -53,6 +53,9 @@ class CodeGenOptions : public CodeGenOptionsBase {
/// The paths to the pass plugins that were registered using -fpass-plugin.
std::vector<std::string> LLVMPassPlugins;
+ // The prefered vector width, if requested by -mprefer-vector-width.
+ std::string PreferVectorWidth;
+
/// List of filenames passed in using the -fembed-offload-object option.
These
/// are offloading binaries containing device images and metadata.
std::vector<std::string> OffloadObjects;
diff --git a/flang/include/flang/Optimizer/Transforms/Passes.td
b/flang/include/flang/Optimizer/Transforms/Passes.td
index b251534e1a8f6..2e932d9ad4a26 100644
--- a/flang/include/flang/Optimizer/Transforms/Passes.td
+++ b/flang/include/flang/Optimizer/Transforms/Passes.td
@@ -418,6 +418,10 @@ def FunctionAttr : Pass<"function-attr",
"mlir::func::FuncOp"> {
"module.">,
Option<"unsafeFPMath", "unsafe-fp-math", "bool", /*default=*/"false",
"Set the unsafe-fp-math attribute on functions in the module.">,
+ Option<"preferVectorWidth", "prefer-vector-width", "std::string",
+ /*default=*/"",
+ "Set the prefer-vector-width attribute on functions in the "
+ "module.">,
Option<"tuneCPU", "tune-cpu", "std::string", /*default=*/"",
"Set the tune-cpu attribute on functions in the module.">,
];
diff --git a/flang/include/flang/Tools/CrossToolHelpers.h
b/flang/include/flang/Tools/CrossToolHelpers.h
index 118695bbe2626..058024a4a04c5 100644
--- a/flang/include/flang/Tools/CrossToolHelpers.h
+++ b/flang/include/flang/Tools/CrossToolHelpers.h
@@ -102,6 +102,7 @@ struct MLIRToLLVMPassPipelineConfig : public
FlangEPCallBacks {
UnsafeFPMath = mathOpts.getAssociativeMath() &&
mathOpts.getReciprocalMath() && NoSignedZerosFPMath &&
ApproxFuncFPMath && mathOpts.getFPContractEnabled();
+ PreferVectorWidth = opts.PreferVectorWidth;
if (opts.InstrumentFunctions) {
InstrumentFunctionEntry = "__cyg_profile_func_enter";
InstrumentFunctionExit = "__cyg_profile_func_exit";
@@ -126,6 +127,8 @@ struct MLIRToLLVMPassPipelineConfig : public
FlangEPCallBacks {
bool NoSignedZerosFPMath =
false; ///< Set no-signed-zeros-fp-math attribute for functions.
bool UnsafeFPMath = false; ///< Set unsafe-fp-math attribute for functions.
+ std::string PreferVectorWidth = ""; ///< Set prefer-vector-width attribute
for
+ ///< functions.
bool NSWOnLoopVarInc = true; ///< Add nsw flag to loop variable increments.
bool EnableOpenMP = false; ///< Enable OpenMP lowering.
std::string InstrumentFunctionEntry =
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp
b/flang/lib/Frontend/CompilerInvocation.cpp
index ba2531819ee5e..122eb56fa0599 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -309,6 +309,20 @@ static void
parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
for (auto *a : args.filtered(clang::driver::options::OPT_fpass_plugin_EQ))
opts.LLVMPassPlugins.push_back(a->getValue());
+ // -mprefer_vector_width option
+ if (const llvm::opt::Arg *a =
+
args.getLastArg(clang::driver::options::OPT_mprefer_vector_width_EQ)) {
+ llvm::StringRef s = a->getValue();
+ unsigned Width;
+ if (s == "none")
+ opts.PreferVectorWidth = "none";
+ else if (s.getAsInteger(10, Width))
+ diags.Report(clang::diag::err_drv_invalid_value)
+ << a->getAsString(args) << a->getValue();
+ else
+ opts.PreferVectorWidth = s.str();
+ }
+
// -fembed-offload-object option
for (auto *a :
args.filtered(clang::driver::options::OPT_fembed_offload_object_EQ))
diff --git a/flang/lib/Frontend/FrontendActions.cpp
b/flang/lib/Frontend/FrontendActions.cpp
index 38dfaadf1dff9..012d0fdfe645f 100644
--- a/flang/lib/Frontend/FrontendActions.cpp
+++ b/flang/lib/Frontend/FrontendActions.cpp
@@ -741,6 +741,8 @@ void CodeGenAction::generateLLVMIR() {
config.VScaleMax = vsr->second;
}
+ config.PreferVectorWidth = opts.PreferVectorWidth;
+
if (ci.getInvocation().getFrontendOpts().features.IsEnabled(
Fortran::common::LanguageFeature::OpenMP))
config.EnableOpenMP = true;
diff --git a/flang/lib/Optimizer/Passes/Pipelines.cpp
b/flang/lib/Optimizer/Passes/Pipelines.cpp
index 77751908e35be..5c1e1b9f77efb 100644
--- a/flang/lib/Optimizer/Passes/Pipelines.cpp
+++ b/flang/lib/Optimizer/Passes/Pipelines.cpp
@@ -354,7 +354,7 @@ void createDefaultFIRCodeGenPassPipeline(mlir::PassManager
&pm,
{framePointerKind, config.InstrumentFunctionEntry,
config.InstrumentFunctionExit, config.NoInfsFPMath, config.NoNaNsFPMath,
config.ApproxFuncFPMath, config.NoSignedZerosFPMath,
config.UnsafeFPMath,
- ""}));
+ config.PreferVectorWidth, ""}));
if (config.EnableOpenMP) {
pm.addNestedPass<mlir::func::FuncOp>(
diff --git a/flang/lib/Optimizer/Transforms/FunctionAttr.cpp
b/flang/lib/Optimizer/Transforms/FunctionAttr.cpp
index 43e4c1a7af3cd..13f447cf738b4 100644
--- a/flang/lib/Optimizer/Transforms/FunctionAttr.cpp
+++ b/flang/lib/Optimizer/Transforms/FunctionAttr.cpp
@@ -36,6 +36,7 @@ class FunctionAttrPass : public
fir::impl::FunctionAttrBase<FunctionAttrPass> {
approxFuncFPMath = options.approxFuncFPMath;
noSignedZerosFPMath = options.noSignedZerosFPMath;
unsafeFPMath = options.unsafeFPMath;
+ preferVectorWidth = options.preferVectorWidth;
}
FunctionAttrPass() {}
void runOnOperation() override;
@@ -102,6 +103,10 @@ void FunctionAttrPass::runOnOperation() {
func->setAttr(
mlir::LLVM::LLVMFuncOp::getUnsafeFpMathAttrName(llvmFuncOpName),
mlir::BoolAttr::get(context, true));
+ if (!preferVectorWidth.empty())
+ func->setAttr(
+ mlir::LLVM::LLVMFuncOp::getPreferVectorWidthAttrName(llvmFuncOpName),
+ mlir::StringAttr::get(context, preferVectorWidth));
LLVM_DEBUG(llvm::dbgs() << "=== End " DEBUG_TYPE " ===\n");
}
diff --git a/flang/test/Driver/prefer-vector-width.f90
b/flang/test/Driver/prefer-vector-width.f90
new file mode 100644
index 0000000000000..d0f5fd28db826
--- /dev/null
+++ b/flang/test/Driver/prefer-vector-width.f90
@@ -0,0 +1,16 @@
+! Test that -mprefer-vector-width works as expected.
+
+! RUN: %flang_fc1 -emit-llvm -o - %s 2>&1| FileCheck %s
--check-prefix=CHECK-DEF
+! RUN: %flang_fc1 -mprefer-vector-width=none -emit-llvm -o - %s 2>&1|
FileCheck %s --check-prefix=CHECK-NONE
+! RUN: %flang_fc1 -mprefer-vector-width=128 -emit-llvm -o - %s 2>&1| FileCheck
%s --check-prefix=CHECK-128
+! RUN: %flang_fc1 -mprefer-vector-width=256 -emit-llvm -o - %s 2>&1| FileCheck
%s --check-prefix=CHECK-256
+! RUN: not %flang_fc1 -mprefer-vector-width=xxx -emit-llvm -o - %s 2>&1|
FileCheck %s --check-prefix=CHECK-INVALID
+
+subroutine func
+end subroutine func
+
+! CHECK-DEF-NOT: attributes #0 = { "prefer-vector-width"={{.*}} }
+! CHECK-NONE: attributes #0 = { "prefer-vector-width"="none" }
+! CHECK-128: attributes #0 = { "prefer-vector-width"="128" }
+! CHECK-256: attributes #0 = { "prefer-vector-width"="256" }
+! CHECK-INVALID:error: invalid value 'xxx' in '-mprefer-vector-width=xxx'
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
index 6fde45ce5c556..c0324d561b77b 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
@@ -1893,6 +1893,7 @@ def LLVM_LLVMFuncOp : LLVM_Op<"func", [
OptionalAttr<FramePointerKindAttr>:$frame_pointer,
OptionalAttr<StrAttr>:$target_cpu,
OptionalAttr<StrAttr>:$tune_cpu,
+ OptionalAttr<StrAttr>:$prefer_vector_width,
OptionalAttr<LLVM_TargetFeaturesAttr>:$target_features,
OptionalAttr<BoolAttr>:$unsafe_fp_math,
OptionalAttr<BoolAttr>:$no_infs_fp_math,
diff --git a/mlir/lib/Target/LLVMIR/ModuleImport.cpp
b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
index b049064fbd31c..85417da798b22 100644
--- a/mlir/lib/Target/LLVMIR/ModuleImport.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
@@ -2636,6 +2636,10 @@ void
ModuleImport::processFunctionAttributes(llvm::Function *func,
funcOp.setTargetFeaturesAttr(
LLVM::TargetFeaturesAttr::get(context, attr.getValueAsString()));
+ if (llvm::Attribute attr = func->getFnAttribute("prefer-vector-width");
+ attr.isStringAttribute())
+ funcOp.setPreferVectorWidth(attr.getValueAsString());
+
if (llvm::Attribute attr = func->getFnAttribute("unsafe-fp-math");
attr.isStringAttribute())
funcOp.setUnsafeFpMath(attr.getValueAsBool());
diff --git a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
index 047e870b7dcd8..2b7f0b11613aa 100644
--- a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
@@ -1540,6 +1540,9 @@ LogicalResult
ModuleTranslation::convertOneFunction(LLVMFuncOp func) {
if (auto tuneCpu = func.getTuneCpu())
llvmFunc->addFnAttr("tune-cpu", *tuneCpu);
+ if (auto preferVectorWidth = func.getPreferVectorWidth())
+ llvmFunc->addFnAttr("prefer-vector-width", *preferVectorWidth);
+
if (auto attr = func.getVscaleRange())
llvmFunc->addFnAttr(llvm::Attribute::getWithVScaleRangeArgs(
getLLVMContext(), attr->getMinRange().getInt(),
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