[MLIR] Fix LivenessAnalysis/RemoveDeadValues handling of dead function arguments

[joker-eph]

In #153973 I added the correctly handling of block arguments, unfortunately this was gated on operation that also have results. This wasn't intentional and this excluded operations like function from being correctly processed.

[llvmbot]

@llvm/pr-subscribers-mlir

@llvm/pr-subscribers-mlir-core

Author: Mehdi Amini (joker-eph)

Changes

In #153973 I added the correctly handling of block arguments, unfortunately this was gated on operation that also have results. This wasn't intentional and this excluded operations like function from being correctly processed.

---

Full diff: https://github.com/llvm/llvm-project/pull/160755.diff

3 Files Affected:

• (modified) mlir/lib/Analysis/DataFlow/LivenessAnalysis.cpp (-2)
• (modified) mlir/lib/Transforms/RemoveDeadValues.cpp (+2-1)
• (modified) mlir/test/Transforms/remove-dead-values.mlir (+34)

diff --git a/mlir/lib/Analysis/DataFlow/LivenessAnalysis.cpp b/mlir/lib/Analysis/DataFlow/LivenessAnalysis.cpp index 65df355216f74..fdb97d5963299 100644 --- a/mlir/lib/Analysis/DataFlow/LivenessAnalysis.cpp +++ b/mlir/lib/Analysis/DataFlow/LivenessAnalysis.cpp @@ -299,8 +299,6 @@ RunLivenessAnalysis::RunLivenessAnalysis(Operation *op) { // The framework doesn't visit operations in dead blocks, so we need to // explicitly mark them as dead. op->walk([&](Operation *op) { - if (op->getNumResults() == 0) - return; for (auto result : llvm::enumerate(op->getResults())) { if (getLiveness(result.value())) continue; diff --git a/mlir/lib/Transforms/RemoveDeadValues.cpp b/mlir/lib/Transforms/RemoveDeadValues.cpp index 0e84b6dd17f29..59983365acfb8 100644 --- a/mlir/lib/Transforms/RemoveDeadValues.cpp +++ b/mlir/lib/Transforms/RemoveDeadValues.cpp @@ -287,7 +287,8 @@ static void processSimpleOp(Operation *op, RunLivenessAnalysis &la, static void processFuncOp(FunctionOpInterface funcOp, Operation *module, RunLivenessAnalysis &la, DenseSet<Value> &nonLiveSet, RDVFinalCleanupList &cl) { - LDBG() << "Processing function op: " << funcOp.getOperation()->getName(); + LDBG() << "Processing function op: " + << OpWithFlags(funcOp, OpPrintingFlags().skipRegions()); if (funcOp.isPublic() || funcOp.isExternal()) { LDBG() << "Function is public or external, skipping: " << funcOp.getOperation()->getName(); diff --git a/mlir/test/Transforms/remove-dead-values.mlir b/mlir/test/Transforms/remove-dead-values.mlir index fa2c145bd3701..33afd54d8113d 100644 --- a/mlir/test/Transforms/remove-dead-values.mlir +++ b/mlir/test/Transforms/remove-dead-values.mlir @@ -615,3 +615,37 @@ module @last_block_not_exit { // CHECK-LABEL: @call_private_but_not_use // CHECK: call @terminated_with_condbr(%false, %true) : (i1, i1) } + +// ----- + +// Test the elimination of function arguments. + +// CHECK-LABEL: func private @single_parameter +// CHECK-SAME: () { +func.func private @single_parameter(%arg0: index) { + return +} + +// CHECK-LABEL: func.func private @mutl_parameter( +// CHECK-SAME: %[[ARG0:.*]]: index) +// CHECK: return %[[ARG0]] +func.func private @mutl_parameter(%arg0: index, %arg1: index, %arg2: index) -> index { + return %arg1 : index +} + +// CHECK-LABEL: func private @eliminate_parameter +// CHECK-SAME: () { +func.func private @eliminate_parameter(%arg0: index, %arg1: index) { + call @single_parameter(%arg0) : (index) -> () + return +} + +// CHECK-LABEL: func @callee +// CHECK-SAME: (%[[ARG0:.*]]: index, %[[ARG1:.*]]: index, %[[ARG2:.*]]: index) +func.func @callee(%arg0: index, %arg1: index, %arg2: index) -> index { +// CHECK: call @eliminate_parameter() : () -> () + call @eliminate_parameter(%arg0, %arg1) : (index, index) -> () +// CHECK: call @mutl_parameter(%[[ARG1]]) : (index) -> index + %res = call @mutl_parameter(%arg0, %arg1, %arg2) : (index, index, index) -> (index) + return %res : index +} \ No newline at end of file 

[linuxlonelyeagle]

Looks great, thanks for doing this.