tianshilei1992 created this revision.
Herald added subscribers: dexonsmith, dang, guansong, yaxunl.
tianshilei1992 requested review of this revision.
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Herald added subscribers: cfe-commits, sstefan1.
Herald added a project: clang.
Currently an OpenMP thread is mapped to a hardware thread. In order to support
SIMD, we have to map an OpenMP thread to a warp (wavefront). This mapping has to
be determined when the kernel is launched, and the execution mode is encoded in
the `int8_t Mode` when calling `__kmpc_target_init`, which is introduced in
D110279 <https://reviews.llvm.org/D110279>. However, we cannot determine if
`simd` is used and then adjust `Mode`
accordingly in current Clang CodeGen because the function call to
`__kmpc_target_init` is emitted before the body of target region.
This patches adds a new clang argument `-fopenmp-target-simd` to emit code that
supports SIMD mapping. When this argument is set, no matter whether there is
`simd` directive in target region, the new mappig is always used. If it is not
set or `-fopenmp-no-target-simd` is set, the existing mapping will be used, and
`simd` directive will be ignored.
The reason we don't reuse `-fopenmp-simd` is the CodeGen of device code shares
some implementation with host code. `-fopenmp-simd` can change CodeGen, which we
don't expect to introduce any unknown effects.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D110286
Files:
clang/docs/ClangCommandLineReference.rst
clang/include/clang/Basic/LangOptions.def
clang/include/clang/Driver/Options.td
clang/lib/Frontend/CompilerInvocation.cpp
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -3782,8 +3782,8 @@
// '-mignore-xcoff-visibility' is implied. The generated command line will
// contain both '-fvisibility default' and '-mignore-xcoff-visibility' and
// subsequent calls to `CreateFromArgs`/`generateCC1CommandLine` will always
- // produce the same arguments.
-
+ // produce the same arguments.
+
if (T.isOSAIX() && (Args.hasArg(OPT_mignore_xcoff_visibility) ||
!Args.hasArg(OPT_fvisibility)))
Opts.IgnoreXCOFFVisibility = 1;
@@ -3863,6 +3863,10 @@
Opts.OpenMP && Args.hasArg(options::OPT_fopenmp_enable_irbuilder);
bool IsTargetSpecified =
Opts.OpenMPIsDevice || Args.hasArg(options::OPT_fopenmp_targets_EQ);
+ Opts.OpenMPTargetSimd =
+ IsTargetSpecified &&
+ Args.hasFlag(options::OPT_fopenmp_target_simd,
+ options::OPT_fno_openmp_target_simd, /*Default=*/false);
Opts.OpenMPTargetNewRuntime =
Opts.OpenMPIsDevice &&
Args.hasArg(options::OPT_fopenmp_target_new_runtime);
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -1805,7 +1805,7 @@
defm protect_parens : BoolFOption<"protect-parens",
LangOpts<"ProtectParens">, DefaultFalse,
- PosFlag<SetTrue, [CoreOption, CC1Option],
+ PosFlag<SetTrue, [CoreOption, CC1Option],
"Determines whether the optimizer honors parentheses when "
"floating-point expressions are evaluated">,
NegFlag<SetFalse>>;
@@ -2406,9 +2406,12 @@
Group<f_Group>, Flags<[CC1Option, NoArgumentUnused, HelpHidden]>;
def fopenmp_simd : Flag<["-"], "fopenmp-simd">, Group<f_Group>, Flags<[CC1Option, NoArgumentUnused]>,
HelpText<"Emit OpenMP code only for SIMD-based constructs.">;
+def fopenmp_target_simd : Flag<["-"], "fopenmp-target-simd">, Group<f_Group>, Flags<[CC1Option, NoArgumentUnused]>,
+ HelpText<"Emit OpenMP target offloading code that supports SIMD execution.">;
def fopenmp_enable_irbuilder : Flag<["-"], "fopenmp-enable-irbuilder">, Group<f_Group>, Flags<[CC1Option, NoArgumentUnused, HelpHidden]>,
HelpText<"Use the experimental OpenMP-IR-Builder codegen path.">;
def fno_openmp_simd : Flag<["-"], "fno-openmp-simd">, Group<f_Group>, Flags<[CC1Option, NoArgumentUnused]>;
+def fno_openmp_target_simd : Flag<["-"], "fno-openmp-target-simd">, Group<f_Group>, Flags<[CC1Option, NoArgumentUnused]>;
def fopenmp_cuda_mode : Flag<["-"], "fopenmp-cuda-mode">, Group<f_Group>,
Flags<[CC1Option, NoArgumentUnused, HelpHidden]>;
def fno_openmp_cuda_mode : Flag<["-"], "fno-openmp-cuda-mode">, Group<f_Group>,
@@ -2548,7 +2551,7 @@
ShouldParseIf<!strconcat("!", open_cl.KeyPath)>;
defm split_stack : BoolFOption<"split-stack",
CodeGenOpts<"EnableSegmentedStacks">, DefaultFalse,
- NegFlag<SetFalse, [], "Wouldn't use segmented stack">,
+ NegFlag<SetFalse, [], "Wouldn't use segmented stack">,
PosFlag<SetTrue, [CC1Option], "Use segmented stack">>;
def fstack_protector_all : Flag<["-"], "fstack-protector-all">, Group<f_Group>,
HelpText<"Enable stack protectors for all functions">;
@@ -4575,7 +4578,7 @@
HelpText<"Enable the old style PARAMETER statement">;
def fintrinsic_modules_path : Separate<["-"], "fintrinsic-modules-path">, Group<f_Group>, MetaVarName<"<dir>">,
HelpText<"Specify where to find the compiled intrinsic modules">,
- DocBrief<[{This option specifies the location of pre-compiled intrinsic modules,
+ DocBrief<[{This option specifies the location of pre-compiled intrinsic modules,
if they are not in the default location expected by the compiler.}]>;
defm backslash : OptInFC1FFlag<"backslash", "Specify that backslash in string introduces an escape character">;
Index: clang/include/clang/Basic/LangOptions.def
===================================================================
--- clang/include/clang/Basic/LangOptions.def
+++ clang/include/clang/Basic/LangOptions.def
@@ -233,6 +233,7 @@
LANGOPT(OpenMP , 32, 0, "OpenMP support and version of OpenMP (31, 40 or 45)")
LANGOPT(OpenMPExtensions , 1, 1, "Enable all Clang extensions for OpenMP directives and clauses")
LANGOPT(OpenMPSimd , 1, 0, "Use SIMD only OpenMP support.")
+LANGOPT(OpenMPTargetSimd , 1, 0, "Use OpenMP target offloading SIMD support.")
LANGOPT(OpenMPUseTLS , 1, 0, "Use TLS for threadprivates or runtime calls")
LANGOPT(OpenMPIsDevice , 1, 0, "Generate code only for OpenMP target device")
LANGOPT(OpenMPCUDAMode , 1, 0, "Generate code for OpenMP pragmas in SIMT/SPMD mode")
@@ -425,7 +426,7 @@
LANGOPT(ArmSveVectorBits, 32, 0, "SVE vector size in bits")
-ENUM_LANGOPT(ExtendIntArgs, ExtendArgsKind, 1, ExtendArgsKind::ExtendTo32,
+ENUM_LANGOPT(ExtendIntArgs, ExtendArgsKind, 1, ExtendArgsKind::ExtendTo32,
"Controls how scalar integer arguments are extended in calls "
"to unprototyped and varargs functions")
Index: clang/docs/ClangCommandLineReference.rst
===================================================================
--- clang/docs/ClangCommandLineReference.rst
+++ clang/docs/ClangCommandLineReference.rst
@@ -2037,6 +2037,10 @@
Emit OpenMP code only for SIMD-based constructs.
+.. option:: -fopenmp-target-simd, -fno-openmp-target-simd
+
+Emit OpenMP target offloading code that supports SIMD execution.
+
.. option:: -fopenmp-version=<arg>
.. option:: -fopenmp-extensions, -fno-openmp-extensions
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