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[flang] Add loop annotation attributes to the loop backedge instead of the loop header's conditional branch #126082

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Merged
merged 3 commits into from
May 14, 2025
Merged

[flang] Add loop annotation attributes to the loop backedge instead of the loop header's conditional branch #126082

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28a8f74
Add loop attr info to the backedge, not condition
ashermancinelli Feb 6, 2025
cd02a91
formatting
ashermancinelli Feb 6, 2025
7f00657
Update tests wrt recent loop metadata changes
ashermancinelli May 13, 2025
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13 changes: 7 additions & 6 deletions flang/lib/Optimizer/Transforms/ControlFlowConverter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -123,23 +123,24 @@ class CfgLoopConv : public mlir::OpRewritePattern<fir::DoLoopOp> {
: terminator->operand_begin();
loopCarried.append(begin, terminator->operand_end());
loopCarried.push_back(itersMinusOne);
rewriter.create<mlir::cf::BranchOp>(loc, conditionalBlock, loopCarried);
auto backEdge =
rewriter.create<mlir::cf::BranchOp>(loc, conditionalBlock, loopCarried);
rewriter.eraseOp(terminator);

// Copy loop annotations from the do loop to the loop back edge.
if (auto ann = loop.getLoopAnnotation())
backEdge->setAttr("loop_annotation", *ann);

// Conditional block
rewriter.setInsertionPointToEnd(conditionalBlock);
auto zero = rewriter.create<mlir::arith::ConstantIndexOp>(loc, 0);
auto comparison = rewriter.create<mlir::arith::CmpIOp>(
loc, arith::CmpIPredicate::sgt, itersLeft, zero);

auto cond = rewriter.create<mlir::cf::CondBranchOp>(
rewriter.create<mlir::cf::CondBranchOp>(
loc, comparison, firstBlock, llvm::ArrayRef<mlir::Value>(), endBlock,
llvm::ArrayRef<mlir::Value>());

// Copy loop annotations from the do loop to the loop entry condition.
if (auto ann = loop.getLoopAnnotation())
cond->setAttr("loop_annotation", *ann);

// The result of the loop operation is the values of the condition block
// arguments except the induction variable on the last iteration.
auto args = loop.getFinalValue()
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4 changes: 3 additions & 1 deletion flang/test/Fir/vector-always.fir
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Expand Up @@ -13,7 +13,9 @@ func.func @_QPvector_always() -> i32 {
%c10_i32 = arith.constant 10 : i32
%c1_i32 = arith.constant 1 : i32
%c10 = arith.constant 10 : index
// CHECK: cf.cond_br %{{.*}}, ^{{.*}}, ^{{.*}} {loop_annotation = #[[ANNOTATION]]}
// CHECK: cf.cond_br
// CHECK-NOT: loop_annotation
// CHECK: cf.br ^{{.*}} {loop_annotation = #[[ANNOTATION]]}
%8:2 = fir.do_loop %arg0 = %c1 to %c10 step %c1 iter_args(%arg1 = %c1_i32) -> (index, i32) attributes {loopAnnotation = #loop_annotation} {
fir.result %c1, %c1_i32 : index, i32
}
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18 changes: 13 additions & 5 deletions flang/test/Integration/unroll.f90
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Expand Up @@ -3,8 +3,10 @@
! CHECK-LABEL: unroll_dir
subroutine unroll_dir
integer :: a(10)
!dir$ unroll
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[UNROLL_ENABLE_FULL_ANNO:.*]]
!dir$ unroll
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[UNROLL_ENABLE_FULL_ANNO:.*]]
do i=1,10
a(i)=i
end do
Expand All @@ -14,7 +16,9 @@ end subroutine unroll_dir
subroutine unroll_dir_0
integer :: a(10)
!dir$ unroll 0
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[UNROLL_DISABLE_ANNO:.*]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[UNROLL_DISABLE_ANNO:.*]]
do i=1,10
a(i)=i
end do
Expand All @@ -24,7 +28,9 @@ end subroutine unroll_dir_0
subroutine unroll_dir_1
integer :: a(10)
!dir$ unroll 1
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[UNROLL_DISABLE_ANNO]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[UNROLL_DISABLE_ANNO]]
do i=1,10
a(i)=i
end do
Expand All @@ -34,7 +40,9 @@ end subroutine unroll_dir_1
subroutine unroll_dir_2
integer :: a(10)
!dir$ unroll 2
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[UNROLL_ENABLE_COUNT_2:.*]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[UNROLL_ENABLE_COUNT_2:.*]]
do i=1,10
a(i)=i
end do
Expand Down
20 changes: 15 additions & 5 deletions flang/test/Integration/unroll_and_jam.f90
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Expand Up @@ -4,7 +4,9 @@
subroutine unroll_and_jam_dir
integer :: a(10)
!dir$ unroll_and_jam 4
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[ANNOTATION:.*]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[ANNOTATION:.*]]
do i=1,10
a(i)=i
end do
Expand All @@ -14,7 +16,9 @@ end subroutine unroll_and_jam_dir
subroutine unroll_and_jam_dir_0
integer :: a(10)
!dir$ unroll_and_jam 0
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[ANNOTATION_DISABLE:.*]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[ANNOTATION_DISABLE:.*]]
do i=1,10
a(i)=i
end do
Expand All @@ -24,7 +28,9 @@ end subroutine unroll_and_jam_dir_0
subroutine unroll_and_jam_dir_1
integer :: a(10)
!dir$ unroll_and_jam 1
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[ANNOTATION_DISABLE]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[ANNOTATION_DISABLE]]
do i=1,10
a(i)=i
end do
Expand All @@ -34,7 +40,9 @@ end subroutine unroll_and_jam_dir_1
subroutine nounroll_and_jam_dir
integer :: a(10)
!dir$ nounroll_and_jam
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[ANNOTATION_DISABLE]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[ANNOTATION_DISABLE]]
do i=1,10
a(i)=i
end do
Expand All @@ -44,7 +52,9 @@ end subroutine nounroll_and_jam_dir
subroutine unroll_and_jam_dir_no_factor
integer :: a(10)
!dir$ unroll_and_jam
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[ANNOTATION_NO_FACTOR:.*]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[ANNOTATION_NO_FACTOR:.*]]
do i=1,10
a(i)=i
end do
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8 changes: 6 additions & 2 deletions flang/test/Integration/vector-always.f90
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,9 @@
subroutine vector_always
integer :: a(10)
!dir$ vector always
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[ANNOTATION:.*]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[ANNOTATION:.*]]
do i=1,10
a(i)=i
end do
Expand All @@ -14,7 +16,9 @@ end subroutine vector_always
subroutine no_vector
integer :: a(10)
!dir$ novector
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[ANNOTATION2:.*]]
! CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}
! CHECK-NOT: !llvm.loop
! CHECK: br label {{.*}}, !llvm.loop ![[ANNOTATION2:.*]]
do i=1,10
a(i)=i
end do
Expand Down