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[flang] Add -f[no-]unroll-loops flag #122906

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Merged
DavidTruby merged 5 commits into from
Jan 16, 2025
Merged

[flang] Add -f[no-]unroll-loops flag #122906

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c9b2e58
[flang] Add -f[no-]unroll-loops flag
DavidTruby Jan 8, 2025
d66a7c6
Fix bad rebase and add compiler->frontend forwarding test
DavidTruby Jan 14, 2025
ac03aad
Fix test on x86
DavidTruby Jan 14, 2025
f27462b
Add integration test
DavidTruby Jan 14, 2025
0141e0d
Switch to i64 to simplify tests
DavidTruby Jan 14, 2025
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4 changes: 2 additions & 2 deletions clang/include/clang/Driver/Options.td
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Expand Up @@ -4157,9 +4157,9 @@ def ftrap_function_EQ : Joined<["-"], "ftrap-function=">, Group<f_Group>,
HelpText<"Issue call to specified function rather than a trap instruction">,
MarshallingInfoString<CodeGenOpts<"TrapFuncName">>;
def funroll_loops : Flag<["-"], "funroll-loops">, Group<f_Group>,
HelpText<"Turn on loop unroller">, Visibility<[ClangOption, CC1Option]>;
HelpText<"Turn on loop unroller">, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>;
def fno_unroll_loops : Flag<["-"], "fno-unroll-loops">, Group<f_Group>,
HelpText<"Turn off loop unroller">, Visibility<[ClangOption, CC1Option]>;
HelpText<"Turn off loop unroller">, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>;
def ffinite_loops: Flag<["-"], "ffinite-loops">, Group<f_Group>,
HelpText<"Assume all non-trivial loops are finite.">, Visibility<[ClangOption, CC1Option]>;
def fno_finite_loops: Flag<["-"], "fno-finite-loops">, Group<f_Group>,
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7 changes: 6 additions & 1 deletion clang/lib/Driver/ToolChains/Flang.cpp
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Expand Up @@ -150,12 +150,17 @@ void Flang::addCodegenOptions(const ArgList &Args,
if (shouldLoopVersion(Args))
CmdArgs.push_back("-fversion-loops-for-stride");

Args.addAllArgs(CmdArgs, {options::OPT_flang_experimental_hlfir,
options::OPT_flang_deprecated_no_hlfir,
options::OPT_fno_ppc_native_vec_elem_order,
options::OPT_fppc_native_vec_elem_order});
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@kiranchandramohan kiranchandramohan Jan 14, 2025

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Why is this added separately from below?

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@DavidTruby DavidTruby Jan 14, 2025

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Bad rebase I think 😓

Args.addAllArgs(CmdArgs,
{options::OPT_flang_experimental_hlfir,
options::OPT_flang_deprecated_no_hlfir,
options::OPT_fno_ppc_native_vec_elem_order,
options::OPT_fppc_native_vec_elem_order,
options::OPT_ftime_report, options::OPT_ftime_report_EQ});
options::OPT_ftime_report, options::OPT_ftime_report_EQ,
options::OPT_funroll_loops, options::OPT_fno_unroll_loops});
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@kiranchandramohan kiranchandramohan Jan 14, 2025

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We can add a forwarding test from the driver to the frontend driver.

}

void Flang::addPicOptions(const ArgList &Args, ArgStringList &CmdArgs) const {
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1 change: 1 addition & 0 deletions flang/include/flang/Frontend/CodeGenOptions.def
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Expand Up @@ -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(LoopVersioning, 1, 0) ///< Enable loop versioning.
CODEGENOPT(UnrollLoops, 1, 0) ///< Enable loop unrolling
CODEGENOPT(AliasAnalysis, 1, 0) ///< Enable alias analysis pass

CODEGENOPT(Underscoring, 1, 1)
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4 changes: 4 additions & 0 deletions flang/lib/Frontend/CompilerInvocation.cpp
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Expand Up @@ -246,6 +246,10 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
clang::driver::options::OPT_fno_loop_versioning, false))
opts.LoopVersioning = 1;

opts.UnrollLoops = args.hasFlag(clang::driver::options::OPT_funroll_loops,
clang::driver::options::OPT_fno_unroll_loops,
(opts.OptimizationLevel > 1));

opts.AliasAnalysis = opts.OptimizationLevel > 0;

// -mframe-pointer=none/non-leaf/all option.
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2 changes: 2 additions & 0 deletions flang/lib/Frontend/FrontendActions.cpp
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Expand Up @@ -1028,6 +1028,8 @@ void CodeGenAction::runOptimizationPipeline(llvm::raw_pwrite_stream &os) {
si.registerCallbacks(pic, &mam);
if (ci.isTimingEnabled())
si.getTimePasses().setOutStream(ci.getTimingStreamLLVM());
pto.LoopUnrolling = opts.UnrollLoops;
pto.LoopInterleaving = opts.UnrollLoops;
llvm::PassBuilder pb(targetMachine, pto, pgoOpt, &pic);

// Attempt to load pass plugins and register their callbacks with PB.
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43 changes: 43 additions & 0 deletions flang/test/HLFIR/unroll-loops.fir
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@@ -0,0 +1,43 @@
// RUN: %flang_fc1 -emit-llvm -O1 -funroll-loops -mllvm -force-vector-width=1 -o- %s | FileCheck %s --check-prefixes=CHECK,UNROLL
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@kiranchandramohan kiranchandramohan Jan 14, 2025

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The test should probably be in Integration directory and possibly a source to LLVM IR test.

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@tarunprabhu tarunprabhu Jan 14, 2025

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A source to (at least) HLFIR test will also check that the -f(no-)unroll loops option has not disappeared from the frontend, and is being passed correctly to fc1.

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@DavidTruby DavidTruby Jan 14, 2025

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I guess we should possibly have all 3? A source to HLFIR, this test, and source->llvmir?

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@DavidTruby DavidTruby Jan 14, 2025 •
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Actually, source->HLFIR isn't useful when the driver test already exists. I'll add a source->llvm integration test.

// RUN: %flang_fc1 -emit-llvm -O2 -mllvm -force-vector-width=1 -o- %s | FileCheck %s --check-prefixes=CHECK,UNROLL
// RUN: %flang_fc1 -emit-llvm -O1 -fno-unroll-loops -mllvm -force-vector-width=1 -o- %s | FileCheck %s --check-prefixes=CHECK,NO-UNROLL
// RUN: %flang_fc1 -emit-llvm -O1 -mllvm -force-vector-width=1 -o- %s | FileCheck %s --check-prefixes=CHECK,NO-UNROLL

// CHECK-LABEL: @unroll
// CHECK-SAME: (ptr nocapture writeonly %[[ARG0:.*]])
func.func @unroll(%arg0: !fir.ref<!fir.array<1000xf64>> {fir.bindc_name = "a"}) {
// CHECK: %[[GEPIV:.*]] = getelementptr i8, ptr %0, i64 -8
%scope = fir.dummy_scope : !fir.dscope
%c1000 = arith.constant 1000 : index
%shape = fir.shape %c1000 : (index) -> !fir.shape<1>
%a:2 = hlfir.declare %arg0(%shape) dummy_scope %scope {uniq_name = "unrollEa"} : (!fir.ref<!fir.array<1000xf64>>, !fir.shape<1>, !fir.dscope) -> (!fir.ref<!fir.array<1000xf64>>, !fir.ref<!fir.array<1000xf64>>)
%c1 = arith.constant 1 : index
fir.do_loop %arg1 = %c1 to %c1000 step %c1 {
// CHECK: [[BLK:.*]]:

// NO-UNROLL-NEXT: %[[PHI:.*]] = phi i64 [ 1, %{{.*}} ], [ %[[NIV:.*]], %[[BLK]] ]
// NO-UNROLL-NEXT: %[[IV_D:.*]] = uitofp nneg i64 %[[PHI]] to double
// NO-UNROLL-NEXT: %[[GEP:.*]] = getelementptr double, ptr %[[GEPIV]], i64 %[[PHI]]
// NO-UNROLL-NEXT: store double %[[IV_D]], ptr %[[GEP]]
// NO-UNROLL-NEXT: %[[NIV:.*]] = add nuw nsw i64 %{{.*}}, 1
// NO-UNROLL-NEXT: %[[EXIT:.*]] = icmp eq i64 %[[NIV]], 1001
// NO-UNROLL-NEXT: br i1 %[[EXIT]], label %{{.*}}, label %[[BLK]]

// UNROLL-NEXT: %[[PHI:.*]] = phi i64 [ 0, %{{.*}} ], [ %[[NIV:.*]], %[[BLK]] ]
// UNROLL-NEXT: %[[IV0:.*]] = or disjoint i64 %[[PHI]], 1
// UNROLL-NEXT: %[[IV1:.*]] = add i64 %[[PHI]], 2
// UNROLL-NEXT: %[[IV0_D:.*]] = uitofp nneg i64 %[[IV0]] to double
// UNROLL-NEXT: %[[IV1_D:.*]] = uitofp nneg i64 %[[IV1]] to double
// UNROLL-NEXT: %[[GEP0:.*]] = getelementptr double, ptr %[[ARG0]], i64 %[[PHI]]
// UNROLL-NEXT: %[[GEP1:.*]] = getelementptr double, ptr %[[GEPIV]], i64 %[[IV1]]
// UNROLL-NEXT: store double %[[IV0_D]], ptr %[[GEP0]]
// UNROLL-NEXT: store double %[[IV1_D]], ptr %[[GEP1]]
// UNROLL-NEXT: %[[NIV:.*]] = add nuw i64 %[[PHI]], 2
// UNROLL-NEXT: %[[EXIT:.*]] = icmp eq i64 %[[NIV]], 1000
// UNROLL-NEXT: br i1 %[[EXIT]], label %{{.*}}, label %[[BLK]]
%iv = fir.convert %arg1 : (index) -> f64
%ai = hlfir.designate %a#0 (%arg1) : (!fir.ref<!fir.array<1000xf64>>, index) -> !fir.ref<f64>
hlfir.assign %iv to %ai : f64, !fir.ref<f64>
}
return
}
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