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Fix RefineCallOpPattern in StablehloRefineShapes to preserve side-effecting callees #2934

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Fix RefineCallOpPattern in StablehloRefineShapes to preserve side-effecting callees #2934

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d283638
Fix RefineCallOpPattern in StablehloRefineShapes to preserve side-eff…
christopherbate Apr 8, 2026
4102d6e
Add SideEffectInterfaces Bazel dep to stablehlo_passes
christopherbate Apr 9, 2026
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1 change: 1 addition & 0 deletions BUILD.bazel
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Original file line number Diff line number Diff line change
Expand Up @@ -1215,6 +1215,7 @@ cc_library(
"@llvm-project//mlir:ReconcileUnrealizedCasts",
"@llvm-project//mlir:Rewrite",
"@llvm-project//mlir:ShapeDialect",
"@llvm-project//mlir:SideEffectInterfaces",
"@llvm-project//mlir:Support",
"@llvm-project//mlir:TensorDialect",
"@llvm-project//mlir:TransformUtils",
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16 changes: 16 additions & 0 deletions stablehlo/tests/transforms/stablehlo_refine_shapes.mlir
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Expand Up @@ -885,6 +885,22 @@ module @refine_call_dimension_argument_not_integer {

// -----

// CHECK-LABEL: module @refine_call_side_effecting_callee
module @refine_call_side_effecting_callee {
func.func public @main() {
// CHECK: call @callee()
call @callee() : () -> ()
return
}
func.func private @callee() {
%0 = stablehlo.constant dense<0> : tensor<i32>
stablehlo.custom_call @side_effect(%0) {has_side_effect = true} : (tensor<i32>) -> ()
return
}
}

// -----

// CHECK-LABEL: func @refine_convert
func.func @refine_convert(%arg0 : tensor<4xf32>) -> tensor<?xi32> {
// CHECK: stablehlo.convert{{.*}} -> tensor<4xi32>
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21 changes: 15 additions & 6 deletions stablehlo/transforms/StablehloRefineShapes.cpp
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Expand Up @@ -45,6 +45,7 @@ limitations under the License.
#include "mlir/IR/Value.h"
#include "mlir/IR/ValueRange.h"
#include "mlir/Interfaces/InferTypeOpInterface.h"
#include "mlir/Interfaces/SideEffectInterfaces.h"
#include "mlir/Rewrite/FrozenRewritePatternSet.h"
#include "mlir/Support/LLVM.h"
#include "mlir/Support/LogicalResult.h"
Expand Down Expand Up @@ -566,13 +567,21 @@ struct RefineCallOpPattern : public OpRewritePattern<func::CallOp> {
std::optional<SmallVector<DenseIntElementsAttr>> constantAttrs =
isConstantFunction(callee);
if (constantAttrs.has_value()) {
SmallVector<Value> constants;
for (auto constAttr : constantAttrs.value()) {
constants.push_back(
ConstantOp::create(rewriter, op.getLoc(), constAttr));
auto sideEffectResult = callee.walk([](Operation* nestedOp) {
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@GleasonK GleasonK Apr 13, 2026

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nit - bool hasSideEffects = callee.walk(...).wasInterrupted(); to make it clear that interruption indicates side effect in the same line

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@GleasonK GleasonK Apr 13, 2026

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Also I'm not sure if this is a complete solution. If there's a call op with a nested call op I don't think this catches its side effects. We had this problem in simplification as well and made a similar method:

stablehlo/stablehlo/transforms/optimization/StablehloAggressiveFolder.cpp

Lines 358 to 375 in a48c8e6

bool hasAnyDeclaredSideEffects(Operation* op) {
if (auto memInterface = dyn_cast<MemoryEffectOpInterface>(op)) {
// Return true if the op explicitly declares any memory effects of its own.
if (!memInterface.hasNoEffect()) return true;
// The op has no direct memory effects. Return false if it has no recursive
// memory effects, either.
if (!op->hasTrait<OpTrait::HasRecursiveMemoryEffects>()) return false;
}
// The op doesn't declare any side effects of its own, but its regions could
// still contain ops that do declare side effects. Recursively check them.
for (Region& region : op->getRegions()) {
for (Operation& nestedOp : region.getOps()) {
if (hasAnyDeclaredSideEffects(&nestedOp)) return true;
}
}
return false;
}

A complete solution would likely require an analysis pass that maps call->side effects and does a full pass to calculate transitive side effects

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@christopherbate christopherbate Apr 15, 2026

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Ok let me see if there's a way I can address this by computing it up front... I already didn't like the walk because the result should be cached

auto effectInterface = dyn_cast<MemoryEffectOpInterface>(nestedOp);
if (effectInterface && !effectInterface.hasNoEffect())
return WalkResult::interrupt();
return WalkResult::advance();
});
if (!sideEffectResult.wasInterrupted()) {
SmallVector<Value> constants;
for (auto constAttr : constantAttrs.value()) {
constants.push_back(
ConstantOp::create(rewriter, op.getLoc(), constAttr));
}
rewriter.replaceOp(op, constants);
return success();
}
rewriter.replaceOp(op, constants);
return success();
}
if (!refinementKey->getGlobalConstants().empty()) {
// Drop the global-constant arguments, but only if necessary, or else we
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