[AArch64] Lower jump table cases threshold to 10 #143632
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@llvm/pr-subscribers-backend-aarch64 Author: Guy David (guy-david) ChangesPrevious stabs at this setting (#71166) hypertuned it for SPEC2017, but Clang's own compilation can benefit from a slightly lower threshold, yielding a 0.3% improvement in compile time, while still not regressing SPEC. Most notable benefactors of this change are:
Test Suite: Full diff: https://github.com/llvm/llvm-project/pull/143632.diff 1 Files Affected:
diff --git a/llvm/lib/Target/AArch64/AArch64Subtarget.cpp b/llvm/lib/Target/AArch64/AArch64Subtarget.cpp
index a28e6bad0dca0..68ed10570a52f 100644
--- a/llvm/lib/Target/AArch64/AArch64Subtarget.cpp
+++ b/llvm/lib/Target/AArch64/AArch64Subtarget.cpp
@@ -73,7 +73,7 @@ static cl::opt<AArch64PAuth::AuthCheckMethod>
cl::values(AUTH_CHECK_METHOD_CL_VALUES_LR));
static cl::opt<unsigned> AArch64MinimumJumpTableEntries(
- "aarch64-min-jump-table-entries", cl::init(13), cl::Hidden,
+ "aarch64-min-jump-table-entries", cl::init(10), cl::Hidden,
cl::desc("Set minimum number of entries to use a jump table on AArch64"));
static cl::opt<unsigned> AArch64StreamingHazardSize(
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Previous stabs at this setting hypertuned it for SPEC2017, but Clang's own compilation can benefit from a slightly lower threshold, yielding a 0.3% improvement in compile time, while still not regressing SPEC. Most notable benefactors of this change are: - llvm::Instruction::getNumSuccessors (11 cases) - llvm::Instruction::getSuccessor (11 cases)
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david-arm
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Jun 18, 2025
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/162/builds/24866 Here is the relevant piece of the build log for the reference |
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Previous stabs at this setting (llvm#71166) hypertuned it for SPEC2017, but Clang's own compilation can benefit from a slightly lower threshold, yielding a 0.3% improvement in compile time, while still not regressing SPEC. Most notable beneficiaries of this change are: - `llvm::Instruction::getNumSuccessors` (11 cases) - `llvm::Instruction::getSuccessor` (11 cases) Test Suite with a bootstrapped build: ``` Tests: 4316 Metric: compile_time Program compile_time lhs rhs diff SingleSour...ce/UnitTests/SignlessTypes/div 0.02 0.02 3.0% SingleSour.../UnitTests/SignlessTypes/cast2 0.02 0.02 2.8% SingleSource/Benchmarks/Misc/flops-4 0.02 0.02 1.9% SingleSour...ebra/solvers/cholesky/cholesky 0.05 0.05 1.8% SingleSour...tTests/2020-01-06-coverage-006 0.02 0.02 1.7% SingleSour...ce/Benchmarks/Stanford/FloatMM 0.03 0.03 1.7% SingleSour...9-04-16-BitfieldInitialization 0.02 0.02 1.7% SingleSour...nitTests/2003-07-08-BitOpsTest 0.02 0.02 1.7% MultiSourc...marks/Prolangs-C++/vcirc/vcirc 0.02 0.02 1.6% MultiSourc...Prolangs-C/fixoutput/fixoutput 0.05 0.05 1.5% SingleSour...h/stencils/jacobi-1d/jacobi-1d 0.04 0.04 1.4% MultiSourc...rks/Prolangs-C++/office/office 0.28 0.28 1.4% SingleSour...arks/Adobe-C++/functionobjects 0.39 0.40 1.3% SingleSour...Tests/2003-10-29-ScalarReplBug 0.02 0.02 1.2% SingleSour...arks/Adobe-C++/stepanov_vector 0.41 0.42 1.2% Geomean difference -0.3% compile_time l/r lhs rhs diff count 4316.000000 4316.000000 469.000000 mean 0.057747 0.057595 -0.003034 std 0.544528 0.543139 0.007625 min 0.000000 0.000000 -0.035294 25% 0.000000 0.000000 -0.007006 50% 0.000000 0.000000 -0.003257 75% 0.000000 0.000000 0.000000 max 18.295300 18.252500 0.030151 ```
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Previous stabs at this setting (llvm#71166) hypertuned it for SPEC2017, but Clang's own compilation can benefit from a slightly lower threshold, yielding a 0.3% improvement in compile time, while still not regressing SPEC. Most notable beneficiaries of this change are: - `llvm::Instruction::getNumSuccessors` (11 cases) - `llvm::Instruction::getSuccessor` (11 cases) Test Suite with a bootstrapped build: ``` Tests: 4316 Metric: compile_time Program compile_time lhs rhs diff SingleSour...ce/UnitTests/SignlessTypes/div 0.02 0.02 3.0% SingleSour.../UnitTests/SignlessTypes/cast2 0.02 0.02 2.8% SingleSource/Benchmarks/Misc/flops-4 0.02 0.02 1.9% SingleSour...ebra/solvers/cholesky/cholesky 0.05 0.05 1.8% SingleSour...tTests/2020-01-06-coverage-006 0.02 0.02 1.7% SingleSour...ce/Benchmarks/Stanford/FloatMM 0.03 0.03 1.7% SingleSour...9-04-16-BitfieldInitialization 0.02 0.02 1.7% SingleSour...nitTests/2003-07-08-BitOpsTest 0.02 0.02 1.7% MultiSourc...marks/Prolangs-C++/vcirc/vcirc 0.02 0.02 1.6% MultiSourc...Prolangs-C/fixoutput/fixoutput 0.05 0.05 1.5% SingleSour...h/stencils/jacobi-1d/jacobi-1d 0.04 0.04 1.4% MultiSourc...rks/Prolangs-C++/office/office 0.28 0.28 1.4% SingleSour...arks/Adobe-C++/functionobjects 0.39 0.40 1.3% SingleSour...Tests/2003-10-29-ScalarReplBug 0.02 0.02 1.2% SingleSour...arks/Adobe-C++/stepanov_vector 0.41 0.42 1.2% Geomean difference -0.3% compile_time l/r lhs rhs diff count 4316.000000 4316.000000 469.000000 mean 0.057747 0.057595 -0.003034 std 0.544528 0.543139 0.007625 min 0.000000 0.000000 -0.035294 25% 0.000000 0.000000 -0.007006 50% 0.000000 0.000000 -0.003257 75% 0.000000 0.000000 0.000000 max 18.295300 18.252500 0.030151 ``` (cherry picked from commit bb1f5c3)
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Previous stabs at this setting (#71166) hypertuned it for SPEC2017, but Clang's own compilation can benefit from a slightly lower threshold, yielding a 0.3% improvement in compile time, while still not regressing SPEC.
Most notable beneficiaries of this change are:
llvm::Instruction::getNumSuccessors(11 cases)llvm::Instruction::getSuccessor(11 cases)Test Suite with a bootstrapped build: