[flang] Add -f[no-]slp-vectorize flags #132801

mrkajetanp · 2025-03-24T18:25:59Z

Add -f[no-]slp-vectorize to the flang driver.
Add corresponding -fvectorize-slp to the flang frontend.

Enable -fslp-vectorize at -O2 and higher in flang to match the current behaviour in clang.

Add -f[no-]slp-vectorize to the flang driver. Add corresponding -fvectorize-slp to the flang frontend. Signed-off-by: Kajetan Puchalski <[email protected]>

mrkajetanp · 2025-03-24T18:26:31Z

cc @tblah @DavidTruby

llvmbot · 2025-03-24T18:26:33Z

@llvm/pr-subscribers-flang-driver
@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-driver

Author: Kajetan Puchalski (mrkajetanp)

Changes

Add -f[no-]slp-vectorize to the flang driver.
Add corresponding -fvectorize-slp to the flang frontend.

Full diff: https://github.com/llvm/llvm-project/pull/132801.diff

6 Files Affected:

(modified) clang/include/clang/Driver/Options.td (+6-3)
(modified) clang/lib/Driver/ToolChains/Flang.cpp (+8)
(modified) flang/include/flang/Frontend/CodeGenOptions.def (+1)
(modified) flang/lib/Frontend/CompilerInvocation.cpp (+3)
(modified) flang/lib/Frontend/FrontendActions.cpp (+1)
(added) flang/test/Driver/slp-vectorize.f90 (+10)

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 59a57c83c6b89..a2cdf9f26fcdf 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -4032,11 +4032,14 @@ def : Flag<["-"], "ftree-vectorize">, Alias<fvectorize>;
 def : Flag<["-"], "fno-tree-vectorize">, Alias<fno_vectorize>;
 }
 
+let Visibility = [ClangOption, FlangOption] in {
 def fslp_vectorize : Flag<["-"], "fslp-vectorize">, Group<f_Group>,
   HelpText<"Enable the superword-level parallelism vectorization passes">;
 def fno_slp_vectorize : Flag<["-"], "fno-slp-vectorize">, Group<f_Group>;
 def : Flag<["-"], "ftree-slp-vectorize">, Alias<fslp_vectorize>;
 def : Flag<["-"], "fno-tree-slp-vectorize">, Alias<fno_slp_vectorize>;
+}
+
 def Wlarge_by_value_copy_def : Flag<["-"], "Wlarge-by-value-copy">,
   HelpText<"Warn if a function definition returns or accepts an object larger "
            "in bytes than a given value">, Flags<[HelpHidden]>;
@@ -7384,6 +7387,9 @@ def mlink_bitcode_file
 def vectorize_loops : Flag<["-"], "vectorize-loops">,
   HelpText<"Run the Loop vectorization passes">,
   MarshallingInfoFlag<CodeGenOpts<"VectorizeLoop">>;
+def vectorize_slp : Flag<["-"], "vectorize-slp">,
+  HelpText<"Run the SLP vectorization passes">,
+  MarshallingInfoFlag<CodeGenOpts<"VectorizeSLP">>;
 } // let Visibility = [CC1Option, FC1Option]
 
 let Visibility = [CC1Option] in {
@@ -7499,9 +7505,6 @@ defm link_builtin_bitcode_postopt: BoolMOption<"link-builtin-bitcode-postopt",
   PosFlag<SetTrue, [], [ClangOption], "Link builtin bitcodes after the "
   "optimization pipeline">,
   NegFlag<SetFalse, [], [ClangOption]>>;
-def vectorize_slp : Flag<["-"], "vectorize-slp">,
-  HelpText<"Run the SLP vectorization passes">,
-  MarshallingInfoFlag<CodeGenOpts<"VectorizeSLP">>;
 def linker_option : Joined<["--"], "linker-option=">,
   HelpText<"Add linker option">,
   MarshallingInfoStringVector<CodeGenOpts<"LinkerOptions">>;
diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp
index 5dbc5cbe77d0a..bb89432d3e58c 100644
--- a/clang/lib/Driver/ToolChains/Flang.cpp
+++ b/clang/lib/Driver/ToolChains/Flang.cpp
@@ -161,6 +161,14 @@ void Flang::addCodegenOptions(const ArgList &Args,
                    options::OPT_fno_vectorize, enableVec))
     CmdArgs.push_back("-vectorize-loops");
 
+  // -fslp-vectorize is enabled based on the optimization level selected.
+  bool EnableSLPVec = shouldEnableVectorizerAtOLevel(Args, true);
+  OptSpecifier SLPVectAliasOption =
+      EnableSLPVec ? options::OPT_O_Group : options::OPT_fslp_vectorize;
+  if (Args.hasFlag(options::OPT_fslp_vectorize, SLPVectAliasOption,
+                   options::OPT_fno_slp_vectorize, EnableSLPVec))
+    CmdArgs.push_back("-vectorize-slp");
+
   if (shouldLoopVersion(Args))
     CmdArgs.push_back("-fversion-loops-for-stride");
 
diff --git a/flang/include/flang/Frontend/CodeGenOptions.def b/flang/include/flang/Frontend/CodeGenOptions.def
index 44cb5a2cdd497..5d6af4271d4f6 100644
--- a/flang/include/flang/Frontend/CodeGenOptions.def
+++ b/flang/include/flang/Frontend/CodeGenOptions.def
@@ -32,6 +32,7 @@ CODEGENOPT(PrepareForThinLTO , 1, 0) ///< Set when -flto=thin is enabled on the
                                      ///< compile step.
 CODEGENOPT(StackArrays, 1, 0) ///< -fstack-arrays (enable the stack-arrays pass)
 CODEGENOPT(VectorizeLoop, 1, 0) ///< Enable loop vectorization.
+CODEGENOPT(VectorizeSLP, 1, 0) ///< Enable SLP vectorization.
 CODEGENOPT(LoopVersioning, 1, 0) ///< Enable loop versioning.
 CODEGENOPT(UnrollLoops, 1, 0) ///< Enable loop unrolling
 CODEGENOPT(AliasAnalysis, 1, 0) ///< Enable alias analysis pass
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index f433ec9966922..652b3d8795ab7 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -246,6 +246,9 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
   if (args.getLastArg(clang::driver::options::OPT_vectorize_loops))
     opts.VectorizeLoop = 1;
 
+  if (args.getLastArg(clang::driver::options::OPT_vectorize_slp))
+    opts.VectorizeSLP = 1;
+
   if (args.hasFlag(clang::driver::options::OPT_floop_versioning,
                    clang::driver::options::OPT_fno_loop_versioning, false))
     opts.LoopVersioning = 1;
diff --git a/flang/lib/Frontend/FrontendActions.cpp b/flang/lib/Frontend/FrontendActions.cpp
index 46ec7550e4140..3e6e98855fe7a 100644
--- a/flang/lib/Frontend/FrontendActions.cpp
+++ b/flang/lib/Frontend/FrontendActions.cpp
@@ -933,6 +933,7 @@ void CodeGenAction::runOptimizationPipeline(llvm::raw_pwrite_stream &os) {
   pto.LoopUnrolling = opts.UnrollLoops;
   pto.LoopInterleaving = opts.UnrollLoops;
   pto.LoopVectorization = opts.VectorizeLoop;
+  pto.SLPVectorization = opts.VectorizeSLP;
 
   llvm::PassBuilder pb(targetMachine, pto, pgoOpt, &pic);
 
diff --git a/flang/test/Driver/slp-vectorize.f90 b/flang/test/Driver/slp-vectorize.f90
new file mode 100644
index 0000000000000..55d4be1a13c71
--- /dev/null
+++ b/flang/test/Driver/slp-vectorize.f90
@@ -0,0 +1,10 @@
+! RUN: %flang -### -S -fslp-vectorize %s 2>&1 | FileCheck -check-prefix=CHECK-SLP-VECTORIZE %s
+! RUN: %flang -### -S -fno-slp-vectorize %s 2>&1 | FileCheck -check-prefix=CHECK-NO-SLP-VECTORIZE %s
+! RUN: %flang -### -S -O1 %s 2>&1 | FileCheck -check-prefix=CHECK-NO-SLP-VECTORIZE %s
+! RUN: %flang -### -S -O2 %s 2>&1 | FileCheck -check-prefix=CHECK-SLP-VECTORIZE %s
+! RUN: %flang -### -S -O3 %s 2>&1 | FileCheck -check-prefix=CHECK-SLP-VECTORIZE %s
+! CHECK-SLP-VECTORIZE: "-vectorize-slp"
+! CHECK-NO-SLP-VECTORIZE-NOT: "-no-vectorize-slp"
+
+program test
+end program

clang/include/clang/Driver/Options.td

clang/lib/Driver/ToolChains/Flang.cpp

flang/test/Driver/slp-vectorize.f90

tarunprabhu · 2025-03-24T18:48:07Z

cc @tblah @DavidTruby

If you are soliciting reviews, you could also use the "Reviewers" box on the top right of this page

flang/test/Driver/slp-vectorize.f90

mrkajetanp · 2025-03-24T19:01:29Z

If you are soliciting reviews, you could also use the "Reviewers" box on the top right of this page

I would, but I do not currently have the right permissions to use the box. Hence the ccs - I need someone else to do it.

tarunprabhu · 2025-03-24T19:06:12Z

If you are soliciting reviews, you could also use the "Reviewers" box on the top right of this page

I would, but I do not currently have the right permissions to use the box. Hence the ccs - I need someone else to do it.

Huh. I didn't realize that one needed special permissions for that.

flang - Expand tests for -fslp-vectorize Signed-off-by: Kajetan Puchalski <[email protected]>

clang/lib/Driver/ToolChains/CommonArgs.cpp

Co-authored-by: Tarun Prabhu <[email protected]> Signed-off-by: Kajetan Puchalski <[email protected]>

flang/test/Driver/slp-vectorize.f90

Signed-off-by: Kajetan Puchalski <[email protected]>

tarunprabhu

Apart from the docstrings, this looks good. Thanks for the changes :-)

clang/lib/Driver/ToolChains/CommonArgs.cpp

Signed-off-by: Kajetan Puchalski <[email protected]>

mrkajetanp · 2025-03-26T14:17:49Z

Apart from the docstrings, this looks good. Thanks for the changes :-)

Done, thanks a lot for the review! :)

DavidTruby

LGTM, thanks!

tarunprabhu · 2025-03-26T17:06:20Z

Is this buildbot failure related: https://lab.llvm.org/buildbot/#/builders/89/builds/19482?

kiranchandramohan · 2025-03-26T17:10:29Z

This patch might partially address the issue raised in #73180

kiranchandramohan · 2025-03-26T17:15:35Z

Is this buildbot failure related: https://lab.llvm.org/buildbot/#/builders/89/builds/19482?

Likely. We shouldn't be generating files in driver tests. For checking output, we have to pipe the output to FileCheck.

mrkajetanp · 2025-03-26T17:18:09Z

Is this buildbot failure related: https://lab.llvm.org/buildbot/#/builders/89/builds/19482?

Ah yes, sorry about that! Just a missing -o /dev/null, I'll post a fix in a moment.

mrkajetanp · 2025-03-26T17:20:13Z

This patch might partially address the issue raised in #73180

Certainly, I tracked a regression in a workload down to flang not running the slp vectorizer. Hence this patch.

mrkajetanp · 2025-03-26T17:27:02Z

The buildbot failure fix is here:
#133128

[flang] Add -f[no-]slp-vectorize flags

d9b2a86

Add -f[no-]slp-vectorize to the flang driver. Add corresponding -fvectorize-slp to the flang frontend. Signed-off-by: Kajetan Puchalski <[email protected]>

llvmbot added clang Clang issues not falling into any other category clang:driver 'clang' and 'clang++' user-facing binaries. Not 'clang-cl' flang:driver flang Flang issues not falling into any other category labels Mar 24, 2025

tarunprabhu requested changes Mar 24, 2025

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clang/include/clang/Driver/Options.td Outdated Show resolved Hide resolved

clang/lib/Driver/ToolChains/Flang.cpp Outdated Show resolved Hide resolved

flang/test/Driver/slp-vectorize.f90 Show resolved Hide resolved

tblah reviewed Mar 24, 2025

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flang/test/Driver/slp-vectorize.f90 Show resolved Hide resolved

tblah requested a review from DavidTruby March 24, 2025 20:59

[flang] [clang] Move -fvectorize and -fslp-vectorize into CommonArgs

e78240d

flang - Expand tests for -fslp-vectorize Signed-off-by: Kajetan Puchalski <[email protected]>

mrkajetanp force-pushed the flang-slp-vectorize branch from 6689d84 to e78240d Compare March 25, 2025 13:22

mrkajetanp requested review from tarunprabhu and tblah March 25, 2025 13:57

tarunprabhu reviewed Mar 25, 2025

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clang/lib/Driver/ToolChains/CommonArgs.cpp Outdated Show resolved Hide resolved

mrkajetanp force-pushed the flang-slp-vectorize branch from a9b7ccb to b45704a Compare March 25, 2025 14:12

[clang] CommonArgs - Fix local variable name case

3258e8e

Co-authored-by: Tarun Prabhu <[email protected]> Signed-off-by: Kajetan Puchalski <[email protected]>

mrkajetanp force-pushed the flang-slp-vectorize branch from b45704a to 3258e8e Compare March 25, 2025 14:35

tblah reviewed Mar 25, 2025

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[flang] test: Add test for absence of slp-vectorizer pass

c8cc32a

Signed-off-by: Kajetan Puchalski <[email protected]>

mrkajetanp requested review from tarunprabhu and tblah March 25, 2025 17:30

tarunprabhu approved these changes Mar 25, 2025

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clang/lib/Driver/ToolChains/CommonArgs.cpp Outdated Show resolved Hide resolved

[clang] CommonArgs - Move handleVectorize* doc comments to .h

e387474

Signed-off-by: Kajetan Puchalski <[email protected]>

DavidTruby approved these changes Mar 26, 2025

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tblah merged commit 529c5b7 into llvm:main Mar 26, 2025
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tblah mentioned this pull request Mar 26, 2025

[flang] Fix slp-vectorize.f90 test #133128

Merged

[flang] Add -f[no-]slp-vectorize flags #132801

[flang] Add -f[no-]slp-vectorize flags #132801

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