[flang] Implement !DIR$ UNROLL [N] #123331
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@llvm/pr-subscribers-flang-parser @llvm/pr-subscribers-flang-fir-hlfir Author: Jean-Didier PAILLEUX (JDPailleux) ChangesThis patch implements support for the UNROLL directive to control how many times a loop should be unrolled. Full diff: https://github.com/llvm/llvm-project/pull/123331.diff 11 Files Affected:
diff --git a/flang/include/flang/Parser/dump-parse-tree.h b/flang/include/flang/Parser/dump-parse-tree.h
index 11725991e9c9a9..8ed44f93a4e8f3 100644
--- a/flang/include/flang/Parser/dump-parse-tree.h
+++ b/flang/include/flang/Parser/dump-parse-tree.h
@@ -208,6 +208,7 @@ class ParseTreeDumper {
NODE(CompilerDirective, NameValue)
NODE(CompilerDirective, Unrecognized)
NODE(CompilerDirective, VectorAlways)
+ NODE(CompilerDirective, Unroll)
NODE(parser, ComplexLiteralConstant)
NODE(parser, ComplexPart)
NODE(parser, ComponentArraySpec)
diff --git a/flang/include/flang/Parser/parse-tree.h b/flang/include/flang/Parser/parse-tree.h
index 00d85aa05fb3a5..2a8020a5f9525f 100644
--- a/flang/include/flang/Parser/parse-tree.h
+++ b/flang/include/flang/Parser/parse-tree.h
@@ -3368,10 +3368,13 @@ struct CompilerDirective {
TUPLE_CLASS_BOILERPLATE(NameValue);
std::tuple<Name, std::optional<std::uint64_t>> t;
};
+ struct Unroll {
+ WRAPPER_CLASS_BOILERPLATE(Unroll, std::optional<std::uint64_t>);
+ };
EMPTY_CLASS(Unrecognized);
CharBlock source;
std::variant<std::list<IgnoreTKR>, LoopCount, std::list<AssumeAligned>,
- VectorAlways, std::list<NameValue>, Unrecognized>
+ VectorAlways, std::list<NameValue>, Unroll, Unrecognized>
u;
};
diff --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
index 37f51d74d23f8f..610c7a58768758 100644
--- a/flang/lib/Lower/Bridge.cpp
+++ b/flang/lib/Lower/Bridge.cpp
@@ -2153,14 +2153,42 @@ class FirConverter : public Fortran::lower::AbstractConverter {
return builder->createIntegerConstant(loc, controlType, 1); // step
}
- void addLoopAnnotationAttr(IncrementLoopInfo &info) {
+ void addLoopAnnotationAttr(
+ IncrementLoopInfo &info,
+ llvm::SmallVectorImpl<const Fortran::parser::CompilerDirective *> &dirs) {
mlir::BoolAttr f = mlir::BoolAttr::get(builder->getContext(), false);
- mlir::LLVM::LoopVectorizeAttr va = mlir::LLVM::LoopVectorizeAttr::get(
- builder->getContext(), /*disable=*/f, {}, {}, {}, {}, {}, {});
- mlir::LLVM::LoopAnnotationAttr la = mlir::LLVM::LoopAnnotationAttr::get(
- builder->getContext(), {}, /*vectorize=*/va, {}, {}, {}, {}, {}, {}, {},
- {}, {}, {}, {}, {}, {});
- info.doLoop.setLoopAnnotationAttr(la);
+ mlir::BoolAttr t = mlir::BoolAttr::get(builder->getContext(), true);
+ mlir::LLVM::LoopVectorizeAttr va;
+ mlir::LLVM::LoopUnrollAttr ua;
+ bool has_attrs = false;
+ for (const auto *dir : dirs) {
+ Fortran::common::visit(
+ Fortran::common::visitors{
+ [&](const Fortran::parser::CompilerDirective::VectorAlways &) {
+ va = mlir::LLVM::LoopVectorizeAttr::get(builder->getContext(),
+ /*disable=*/f, {}, {},
+ {}, {}, {}, {});
+ has_attrs = true;
+ },
+ [&](const Fortran::parser::CompilerDirective::Unroll &u) {
+ mlir::IntegerAttr countAttr;
+ if (u.v.has_value()) {
+ countAttr = builder->getIntegerAttr(builder->getI64Type(),
+ u.v.value());
+ }
+ ua = mlir::LLVM::LoopUnrollAttr::get(
+ builder->getContext(), /*disable=*/f, /*count*/ countAttr,
+ {}, /*full*/ u.v.has_value() ? f : t, {}, {}, {});
+ has_attrs = true;
+ },
+ [&](const auto &) {}},
+ dir->u);
+ }
+ mlir::LLVM::LoopAnnotationAttr la = mlir::LLVM::LoopAnnotationAttr::get(
+ builder->getContext(), {}, /*vectorize=*/va, {}, /*unroll*/ ua, {}, {},
+ {}, {}, {}, {}, {}, {}, {}, {}, {});
+ if (has_attrs)
+ info.doLoop.setLoopAnnotationAttr(la);
}
/// Generate FIR to begin a structured or unstructured increment loop nest.
@@ -2259,14 +2287,7 @@ class FirConverter : public Fortran::lower::AbstractConverter {
if (info.hasLocalitySpecs())
handleLocalitySpecs(info);
- for (const auto *dir : dirs) {
- Fortran::common::visit(
- Fortran::common::visitors{
- [&](const Fortran::parser::CompilerDirective::VectorAlways
- &d) { addLoopAnnotationAttr(info); },
- [&](const auto &) {}},
- dir->u);
- }
+ addLoopAnnotationAttr(info, dirs);
continue;
}
@@ -2818,6 +2839,9 @@ class FirConverter : public Fortran::lower::AbstractConverter {
[&](const Fortran::parser::CompilerDirective::VectorAlways &) {
attachDirectiveToLoop(dir, &eval);
},
+ [&](const Fortran::parser::CompilerDirective::Unroll &) {
+ attachDirectiveToLoop(dir, &eval);
+ },
[&](const auto &) {}},
dir.u);
}
diff --git a/flang/lib/Parser/Fortran-parsers.cpp b/flang/lib/Parser/Fortran-parsers.cpp
index 7cb35c1f173bb6..b5bcb53a127613 100644
--- a/flang/lib/Parser/Fortran-parsers.cpp
+++ b/flang/lib/Parser/Fortran-parsers.cpp
@@ -1293,6 +1293,7 @@ TYPE_PARSER(construct<StatOrErrmsg>("STAT =" >> statVariable) ||
// !DIR$ IGNORE_TKR [ [(tkrdmac...)] name ]...
// !DIR$ LOOP COUNT (n1[, n2]...)
// !DIR$ name[=value] [, name[=value]]...
+// !DIR$ UNROLL [n]
// !DIR$ <anything else>
constexpr auto ignore_tkr{
"IGNORE_TKR" >> optionalList(construct<CompilerDirective::IgnoreTKR>(
@@ -1305,11 +1306,14 @@ constexpr auto assumeAligned{"ASSUME_ALIGNED" >>
indirect(designator), ":"_tok >> digitString64))};
constexpr auto vectorAlways{
"VECTOR ALWAYS" >> construct<CompilerDirective::VectorAlways>()};
+constexpr auto unroll{
+ "UNROLL" >> construct<CompilerDirective::Unroll>(maybe(digitString64))};
TYPE_PARSER(beginDirective >> "DIR$ "_tok >>
sourced((construct<CompilerDirective>(ignore_tkr) ||
construct<CompilerDirective>(loopCount) ||
construct<CompilerDirective>(assumeAligned) ||
construct<CompilerDirective>(vectorAlways) ||
+ construct<CompilerDirective>(unroll) ||
construct<CompilerDirective>(
many(construct<CompilerDirective::NameValue>(
name, maybe(("="_tok || ":"_tok) >> digitString64))))) /
diff --git a/flang/lib/Parser/unparse.cpp b/flang/lib/Parser/unparse.cpp
index 7bf404bba2c3e4..8c70564de16650 100644
--- a/flang/lib/Parser/unparse.cpp
+++ b/flang/lib/Parser/unparse.cpp
@@ -1847,6 +1847,10 @@ class UnparseVisitor {
[&](const std::list<CompilerDirective::NameValue> &names) {
Walk("!DIR$ ", names, " ");
},
+ [&](const CompilerDirective::Unroll &unroll) {
+ Word("!DIR$ UNROLL");
+ Walk(" ", unroll.v);
+ },
[&](const CompilerDirective::Unrecognized &) {
Word("!DIR$ ");
Word(x.source.ToString());
diff --git a/flang/lib/Semantics/canonicalize-directives.cpp b/flang/lib/Semantics/canonicalize-directives.cpp
index 739bc3c1992ba6..d521ab3fdb1b13 100644
--- a/flang/lib/Semantics/canonicalize-directives.cpp
+++ b/flang/lib/Semantics/canonicalize-directives.cpp
@@ -54,7 +54,9 @@ bool CanonicalizeDirectives(
}
static bool IsExecutionDirective(const parser::CompilerDirective &dir) {
- return std::holds_alternative<parser::CompilerDirective::VectorAlways>(dir.u);
+ return std::holds_alternative<parser::CompilerDirective::VectorAlways>(
+ dir.u) ||
+ std::holds_alternative<parser::CompilerDirective::Unroll>(dir.u);
}
void CanonicalizationOfDirectives::Post(parser::SpecificationPart &spec) {
@@ -110,6 +112,9 @@ void CanonicalizationOfDirectives::Post(parser::Block &block) {
common::visitors{[&](parser::CompilerDirective::VectorAlways &) {
CheckLoopDirective(*dir, block, it);
},
+ [&](parser::CompilerDirective::Unroll &) {
+ CheckLoopDirective(*dir, block, it);
+ },
[&](auto &) {}},
dir->u);
}
diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index f3c2a5bf094d04..ebcc29570d5716 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -9245,7 +9245,8 @@ void ResolveNamesVisitor::Post(const parser::AssignedGotoStmt &x) {
}
void ResolveNamesVisitor::Post(const parser::CompilerDirective &x) {
- if (std::holds_alternative<parser::CompilerDirective::VectorAlways>(x.u)) {
+ if (std::holds_alternative<parser::CompilerDirective::VectorAlways>(x.u) ||
+ std::holds_alternative<parser::CompilerDirective::Unroll>(x.u)) {
return;
}
if (const auto *tkr{
diff --git a/flang/test/Integration/unroll.f90 b/flang/test/Integration/unroll.f90
new file mode 100644
index 00000000000000..9d69605e10d1b3
--- /dev/null
+++ b/flang/test/Integration/unroll.f90
@@ -0,0 +1,16 @@
+! RUN: %flang_fc1 -emit-llvm -o - %s | FileCheck %s
+
+! CHECK-LABEL: unroll_dir
+subroutine unroll_dir
+ integer :: a(10)
+ !dir$ unroll
+ ! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[ANNOTATION:.*]]
+ do i=1,10
+ a(i)=i
+ end do
+end subroutine unroll_dir
+
+! CHECK: ![[ANNOTATION]] = distinct !{![[ANNOTATION]], ![[UNROLL:.*]], ![[UNROLL_FULL:.*]]}
+! CHECK: ![[UNROLL]] = !{!"llvm.loop.unroll.enable"}
+! CHECK: ![[UNROLL_FULL]] = !{!"llvm.loop.unroll.full"}
+
diff --git a/flang/test/Lower/unroll.f90 b/flang/test/Lower/unroll.f90
new file mode 100644
index 00000000000000..229755200fd8d8
--- /dev/null
+++ b/flang/test/Lower/unroll.f90
@@ -0,0 +1,27 @@
+! RUN: %flang_fc1 -emit-hlfir -o - %s | FileCheck %s
+
+! CHECK: #loop_unroll = #llvm.loop_unroll<disable = false, full = true>
+! CHECK: #loop_annotation = #llvm.loop_annotation<unroll = #loop_unroll>
+
+! CHECK-LABEL: unroll_dir
+subroutine unroll_dir
+ integer :: a(10)
+ !dir$ unroll
+ !CHECK: fir.do_loop {{.*}} attributes {loopAnnotation = #loop_annotation}
+ do i=1,10
+ a(i)=i
+ end do
+end subroutine unroll_dir
+
+
+! CHECK-LABEL: intermediate_directive
+subroutine intermediate_directive
+ integer :: a(10)
+ !dir$ unroll
+ !dir$ unknown
+ !CHECK: fir.do_loop {{.*}} attributes {loopAnnotation = #loop_annotation}
+ do i=1,10
+ a(i)=i
+ end do
+end subroutine intermediate_directive
+
diff --git a/flang/test/Parser/compiler-directives.f90 b/flang/test/Parser/compiler-directives.f90
index 246eaf985251c6..f372a9f533a355 100644
--- a/flang/test/Parser/compiler-directives.f90
+++ b/flang/test/Parser/compiler-directives.f90
@@ -35,3 +35,14 @@ subroutine vector_always
do i=1,10
enddo
end subroutine
+
+subroutine unroll
+ !dir$ unroll
+ ! CHECK: !DIR$ UNROLL
+ do i=1,10
+ enddo
+ !dir$ unroll 2
+ ! CHECK: !DIR$ UNROLL 2
+ do i=1,10
+ enddo
+end subroutine
diff --git a/flang/test/Semantics/loop-directives.f90 b/flang/test/Semantics/loop-directives.f90
index 58fb9b8082bc1a..e20c0c9d042dbf 100644
--- a/flang/test/Semantics/loop-directives.f90
+++ b/flang/test/Semantics/loop-directives.f90
@@ -4,11 +4,15 @@
subroutine empty
! WARNING: A DO loop must follow the VECTOR ALWAYS directive
!dir$ vector always
+ ! WARNING: A DO loop must follow the UNROLL directive
+ !dir$ unroll
end subroutine empty
subroutine non_do
! WARNING: A DO loop must follow the VECTOR ALWAYS directive
!dir$ vector always
+ ! WARNING: A DO loop must follow the UNROLL directive
+ !dir$ unroll
a = 1
end subroutine non_do
@@ -16,6 +20,8 @@ subroutine execution_part
do i=1,10
! WARNING: A DO loop must follow the VECTOR ALWAYS directive
!dir$ vector always
+ ! WARNING: A DO loop must follow the UNROLL directive
+ !dir$ unroll
end do
end subroutine execution_part
@@ -28,3 +34,13 @@ subroutine test_vector_always_before_acc(a, b, c)
a(i) = b(i) + c(i)
enddo
end subroutine
+
+! OK
+subroutine test_unroll_before_acc(a, b, c)
+ real, dimension(10) :: a,b,c
+ !dir$ unroll
+ !$acc loop
+ do i=1,N
+ a(i) = b(i) + c(i)
+ enddo
+end subroutine
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Thank you! This will be really useful for me. I won't approve myself since I'm not familiar with the frontend, but the tests exhibit exactly the behavior I was looking for with the metadata attached to the loop backedge in the llvm ir. |
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✅ With the latest revision this PR passed the C/C++ code formatter. |
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Logic looks great to me, please wait for @DavidTruby's feedback who worked on VectorAlways and may have more insight here. Thanks!
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LGTM, seems in keeping with what I did for vector always. Thanks!
| builder->getContext(), {}, /*vectorize=*/va, {}, /*unroll*/ ua, {}, {}, | ||
| {}, {}, {}, {}, {}, {}, {}, {}, {}); | ||
| if (has_attrs) | ||
| info.doLoop.setLoopAnnotationAttr(la); |
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nit: I think you can just always add the la to the loop, regardless of if there were any attrs; if la is full of empty attrs it will just not do anything. So I don't think we need the has_attrs variable.
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Hi @DavidTruby , thanks for your feedback! About your question, I added the has_attrs because having moved your loop into this function, if dirs is empty, it will return an empty LoopAnnotationAttr and the attribute {loopAnnotation = #llvm.loop_annotation<>} will be put in the IR on all loops having no attached directives and many Flang tests will fail.
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@klausler Hi, does this approach to integrating the new directive is OK for you? |
Please verify with a test that the new directive appears properly in the output of |
This is normally already done in this test : |
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Hello, if there is no other review, is it possible for someone to do the merge? |
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@JDPailleux Congratulations on having your first Pull Request (PR) merged into the LLVM Project! Your changes will be combined with recent changes from other authors, then tested by our build bots. If there is a problem with a build, you may receive a report in an email or a comment on this PR. Please check whether problems have been caused by your change specifically, as the builds can include changes from many authors. It is not uncommon for your change to be included in a build that fails due to someone else's changes, or infrastructure issues. How to do this, and the rest of the post-merge process, is covered in detail here. If your change does cause a problem, it may be reverted, or you can revert it yourself. This is a normal part of LLVM development. You can fix your changes and open a new PR to merge them again. If you don't get any reports, no action is required from you. Your changes are working as expected, well done! |
…nd 1 (#126170) #123331 added support for the unrolling directive. In the presence of an explicit unrolling factor, that unrolling factor would be unconditionally passed into the metadata even when it was 1 or 0. These special cases should instead disable unrolling. Adding an explicit unrolling factor of 0 triggered this assertion which is fixed by this patch: ``` unsigned int unrollCountPragmaValue(const llvm::Loop*): Assertion `Count >= 1 && "Unroll count must be positive."' failed. ``` Updated tests and documentation.
…tors of 0 and 1 (#126170) llvm/llvm-project#123331 added support for the unrolling directive. In the presence of an explicit unrolling factor, that unrolling factor would be unconditionally passed into the metadata even when it was 1 or 0. These special cases should instead disable unrolling. Adding an explicit unrolling factor of 0 triggered this assertion which is fixed by this patch: ``` unsigned int unrollCountPragmaValue(const llvm::Loop*): Assertion `Count >= 1 && "Unroll count must be positive."' failed. ``` Updated tests and documentation.
…nd 1 (llvm#126170) llvm#123331 added support for the unrolling directive. In the presence of an explicit unrolling factor, that unrolling factor would be unconditionally passed into the metadata even when it was 1 or 0. These special cases should instead disable unrolling. Adding an explicit unrolling factor of 0 triggered this assertion which is fixed by this patch: ``` unsigned int unrollCountPragmaValue(const llvm::Loop*): Assertion `Count >= 1 && "Unroll count must be positive."' failed. ``` Updated tests and documentation.
…nd 1 (llvm#126170) llvm#123331 added support for the unrolling directive. In the presence of an explicit unrolling factor, that unrolling factor would be unconditionally passed into the metadata even when it was 1 or 0. These special cases should instead disable unrolling. Adding an explicit unrolling factor of 0 triggered this assertion which is fixed by this patch: ``` unsigned int unrollCountPragmaValue(const llvm::Loop*): Assertion `Count >= 1 && "Unroll count must be positive."' failed. ``` Updated tests and documentation.
6 participants
This patch implements support for the UNROLL directive to control how many times a loop should be unrolled.
It must be placed immediately before a
DO LOOPand applies only to the loop that follows. N is an integer that specifying the unrolling factor.This is done by adding an attribute to the branch into the loop in LLVM to indicate that the loop should unrolled.
The code pushed to support the directive
VECTOR ALWAYShas been modified to take account of the fact that several directives can be used before aDO LOOP.