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Merged
merged 3 commits into from
Aug 12, 2024
Merged

Enable attaching LLVM loop annotations to scf.for #102562

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c64eca0
remove redundant move in return statement
XiaoleiShi-NV Apr 30, 2024
8cc0c08
Enable to carry the annotation of
XiaoleiShi-NV Aug 9, 2024
ad9f1cb
revert unwanted changes
XiaoleiShi-NV Aug 9, 2024
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16 changes: 13 additions & 3 deletions mlir/lib/Conversion/SCFToControlFlow/SCFToControlFlow.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@

#include "mlir/Dialect/Arith/IR/Arith.h"
#include "mlir/Dialect/ControlFlow/IR/ControlFlowOps.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/Dialect/SCF/IR/SCF.h"
#include "mlir/IR/Builders.h"
#include "mlir/IR/BuiltinOps.h"
Expand Down Expand Up @@ -369,9 +370,18 @@ LogicalResult ForLowering::matchAndRewrite(ForOp forOp,
auto comparison = rewriter.create<arith::CmpIOp>(
loc, arith::CmpIPredicate::slt, iv, upperBound);

rewriter.create<cf::CondBranchOp>(loc, comparison, firstBodyBlock,
ArrayRef<Value>(), endBlock,
ArrayRef<Value>());
auto condBranchOp = rewriter.create<cf::CondBranchOp>(
loc, comparison, firstBodyBlock, ArrayRef<Value>(), endBlock,
ArrayRef<Value>());

// Let the CondBranchOp carry the LLVM attributes from the ForOp, such as the
// llvm.loop_annotation attribute.
SmallVector<NamedAttribute> llvmAttrs;
llvm::copy_if(forOp->getAttrs(), std::back_inserter(llvmAttrs),
[](auto attr) {
return isa<LLVM::LLVMDialect>(attr.getValue().getDialect());
});
condBranchOp->setDiscardableAttrs(llvmAttrs);
// The result of the loop operation is the values of the condition block
// arguments except the induction variable on the last iteration.
rewriter.replaceOp(forOp, conditionBlock->getArguments().drop_front());
Expand Down
24 changes: 23 additions & 1 deletion mlir/test/Conversion/SCFToControlFlow/convert-to-cfg.mlir
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@@ -1,4 +1,4 @@
// RUN: mlir-opt -allow-unregistered-dialect -convert-scf-to-cf %s | FileCheck %s
// RUN: mlir-opt -allow-unregistered-dialect -convert-scf-to-cf -split-input-file %s | FileCheck %s

// CHECK-LABEL: func @simple_std_for_loop(%{{.*}}: index, %{{.*}}: index, %{{.*}}: index) {
// CHECK-NEXT: cf.br ^bb1(%{{.*}} : index)
Expand Down Expand Up @@ -675,3 +675,25 @@ func.func @forall(%num_threads: index) {
}
return
}

// -----

// CHECK: #loop_unroll = #llvm.loop_unroll<disable = true>
// CHECK-NEXT: #loop_unroll1 = #llvm.loop_unroll<full = true>
// CHECK-NEXT: #[[NO_UNROLL:.*]] = #llvm.loop_annotation<unroll = #loop_unroll>
// CHECK-NEXT: #[[FULL_UNROLL:.*]] = #llvm.loop_annotation<unroll = #loop_unroll1>
// CHECK: cf.cond_br %{{.*}}, ^bb2, ^bb6 {llvm.loop_annotation = #[[NO_UNROLL]]}
// CHECK: cf.cond_br %{{.*}}, ^bb4, ^bb5 {llvm.loop_annotation = #[[FULL_UNROLL]]}
#no_unroll = #llvm.loop_annotation<unroll = <disable = true>>
#full_unroll = #llvm.loop_annotation<unroll = <full = true>>
func.func @simple_std_for_loops_annotation(%arg0 : index, %arg1 : index, %arg2 : index) {
scf.for %i0 = %arg0 to %arg1 step %arg2 {
%c0 = arith.constant 0 : index
%c1 = arith.constant 1 : index
%c4 = arith.constant 4 : index
scf.for %i1 = %c0 to %c4 step %c1 {
%c1_0 = arith.constant 1 : index
} {llvm.loop_annotation = #full_unroll}
} {llvm.loop_annotation = #no_unroll}
return
}