[Mlir-commits] [mlir] [mlir][transform] Update transform.loop.peel (PR #67482)

Andrzej WarzyƄski llvmlistbot at llvm.org
Tue Sep 26 13:11:43 PDT 2023


https://github.com/banach-space created https://github.com/llvm/llvm-project/pull/67482

This patch updates `transform.loop.peel` so that this Op returns two
rather than one handle:
  * one for the peeled loop, and
  * one for the remainder loop.
Also, following this change this Op will fail if peeling fails. This is
consistent with other similar Ops that also fail if no transformation
takes place.


>From a7336c0c5863b5b3f28c5d83ca3815f3d6241216 Mon Sep 17 00:00:00 2001
From: Andrzej Warzynski <andrzej.warzynski at arm.com>
Date: Tue, 26 Sep 2023 19:57:30 +0000
Subject: [PATCH] [mlir][transform] Update transform.loop.peel

This patch updates `transform.loop.peel` so that this Op returns two
rather than one handle:
  * one for the peeled loop, and
  * one for the remainder loop.
Also, following this change this Op will fail if peeling fails. This is
consistent with other similar Ops that also fail if no transformation
takes place.
---
 .../SCF/TransformOps/SCFTransformOps.td       | 19 +++++++++---------
 .../SCF/TransformOps/SCFTransformOps.cpp      | 14 +++++++------
 .../Dialect/Linalg/transform-op-fuse.mlir     |  2 +-
 .../Dialect/SCF/transform-ops-invalid.mlir    | 20 +++++++++++++++++++
 mlir/test/Dialect/SCF/transform-ops.mlir      |  2 +-
 5 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/mlir/include/mlir/Dialect/SCF/TransformOps/SCFTransformOps.td b/mlir/include/mlir/Dialect/SCF/TransformOps/SCFTransformOps.td
index 207a004c54ef5af..3adf5f0dc97dd5a 100644
--- a/mlir/include/mlir/Dialect/SCF/TransformOps/SCFTransformOps.td
+++ b/mlir/include/mlir/Dialect/SCF/TransformOps/SCFTransformOps.td
@@ -142,23 +142,22 @@ def LoopPeelOp : Op<Transform_Dialect, "loop.peel",
 
      This operation ignores non-scf::ForOp ops and drops them in the return.
 
-     This operation always succeeds and returns the scf::ForOp with the
-     postcondition: "the loop trip count is divisible by the step".
-     This operation may return the same unmodified loop handle when peeling did
-     not modify the IR (i.e. the loop trip count was already divisible).
+     This operation returns two scf::ForOp, with the first Op satisfying the
+     postcondition: "the loop trip count is divisible by the step". The second
+     loop Op contains the remaining iteration. Note that even though the
+     Payload IR modification may be performed in-place, this operation consumes
+     the operand handle and produces a new one.
 
-     Note that even though the Payload IR modification may be performed
-     in-place, this operation consumes the operand handle and produces a new
-     one.
+     #### Return Modes
 
-     TODO: Return both the peeled loop and the remainder loop.
+     Produces a definite failure if peeling fails.
   }];
 
   let arguments =
       (ins Transform_ScfForOp:$target,
            DefaultValuedAttr<BoolAttr, "false">:$fail_if_already_divisible);
-  // TODO: Return both the peeled loop and the remainder loop.
-  let results = (outs TransformHandleTypeInterface:$transformed);
+  let results = (outs TransformHandleTypeInterface:$peeled_loop,
+                      TransformHandleTypeInterface:$remainder_loop);
 
   let assemblyFormat =
     "$target attr-dict `:` functional-type(operands, results)";
diff --git a/mlir/lib/Dialect/SCF/TransformOps/SCFTransformOps.cpp b/mlir/lib/Dialect/SCF/TransformOps/SCFTransformOps.cpp
index d7e8c38478ced1a..65d503d7c4ad8b8 100644
--- a/mlir/lib/Dialect/SCF/TransformOps/SCFTransformOps.cpp
+++ b/mlir/lib/Dialect/SCF/TransformOps/SCFTransformOps.cpp
@@ -226,14 +226,16 @@ transform::LoopPeelOp::applyToOne(transform::TransformRewriter &rewriter,
                                   transform::ApplyToEachResultList &results,
                                   transform::TransformState &state) {
   scf::ForOp result;
-  // This helper returns failure when peeling does not occur (i.e. when the IR
-  // is not modified). This is not a failure for the op as the postcondition:
-  //    "the loop trip count is divisible by the step"
-  // is valid.
   LogicalResult status =
       scf::peelForLoopAndSimplifyBounds(rewriter, target, result);
-  // TODO: Return both the peeled loop and the remainder loop.
-  results.push_back(failed(status) ? target : result);
+  if (failed(status)) {
+    DiagnosedSilenceableFailure diag = emitSilenceableError()
+                                       << "failed to peel";
+    return diag;
+  }
+  results.push_back(target);
+  results.push_back(result);
+
   return DiagnosedSilenceableFailure::success();
 }
 
diff --git a/mlir/test/Dialect/Linalg/transform-op-fuse.mlir b/mlir/test/Dialect/Linalg/transform-op-fuse.mlir
index d3772e9c04eef52..72c61661b55efd3 100644
--- a/mlir/test/Dialect/Linalg/transform-op-fuse.mlir
+++ b/mlir/test/Dialect/Linalg/transform-op-fuse.mlir
@@ -48,7 +48,7 @@ transform.sequence failures(propagate) {
   %0 = transform.structured.match ops{["linalg.elemwise_binary"]} in %arg1 : (!transform.any_op) -> !transform.any_op
   %1, %loops:2 = transform.structured.fuse %0 {tile_sizes = [32, 32], tile_interchange = [0, 1]}
     : (!transform.any_op) -> (!transform.any_op, !transform.op<"scf.for">, !transform.any_op)
-  transform.loop.peel %loops#0 : (!transform.op<"scf.for">) -> !transform.any_op
+  transform.loop.peel %loops#0 : (!transform.op<"scf.for">) -> (!transform.any_op, !transform.any_op)
 }
 
 // -----
diff --git a/mlir/test/Dialect/SCF/transform-ops-invalid.mlir b/mlir/test/Dialect/SCF/transform-ops-invalid.mlir
index b69ea0f5975cd80..e8212f500e693ad 100644
--- a/mlir/test/Dialect/SCF/transform-ops-invalid.mlir
+++ b/mlir/test/Dialect/SCF/transform-ops-invalid.mlir
@@ -59,3 +59,23 @@ transform.sequence failures(propagate) {
   // expected-error @below {{failed to outline}}
   transform.loop.outline %0 {func_name = "foo"} : (!transform.any_op) -> (!transform.any_op, !transform.any_op)
 }
+
+// -----
+
+func.func @test_loops_do_not_get_peeled() {
+  %lb = arith.constant 0 : index
+  %ub = arith.constant 40 : index
+  %step = arith.constant 5 : index
+  scf.for %i = %lb to %ub step %step {
+    arith.addi %i, %i : index
+  }
+  return
+}
+
+transform.sequence failures(propagate) {
+^bb1(%arg1: !transform.any_op):
+  %0 = transform.structured.match ops{["arith.addi"]} in %arg1 : (!transform.any_op) -> !transform.any_op
+  %1 = transform.loop.get_parent_for %0 : (!transform.any_op) -> !transform.op<"scf.for">
+  // expected-error @below {{failed to peel}}
+  transform.loop.peel %1 : (!transform.op<"scf.for">) -> (!transform.any_op, !transform.any_op)
+}
diff --git a/mlir/test/Dialect/SCF/transform-ops.mlir b/mlir/test/Dialect/SCF/transform-ops.mlir
index 7718ebcd1fc6ae0..779e750fb500326 100644
--- a/mlir/test/Dialect/SCF/transform-ops.mlir
+++ b/mlir/test/Dialect/SCF/transform-ops.mlir
@@ -107,7 +107,7 @@ transform.sequence failures(propagate) {
 ^bb1(%arg1: !transform.any_op):
   %0 = transform.structured.match ops{["arith.addi"]} in %arg1 : (!transform.any_op) -> !transform.any_op
   %1 = transform.loop.get_parent_for %0 : (!transform.any_op) -> !transform.op<"scf.for">
-  transform.loop.peel %1 : (!transform.op<"scf.for">) -> !transform.any_op
+  transform.loop.peel %1 : (!transform.op<"scf.for">) -> (!transform.any_op, !transform.any_op)
 }
 
 // -----



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