[Mlir-commits] [mlir] Enable LICM for ops with only read side effects in scf.for (PR #120302)

[donald chen]

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@@ -56,48 +56,117 @@ static bool canBeHoisted(Operation *op,
       op, [&](OpOperand &operand) { return definedOutside(operand.get()); });
 }
 
+static bool dependsOnGuarded(Operation *op,
+                             function_ref<bool(OpOperand &)> condition) {
+  auto walkFn = [&](Operation *child) {
+    for (OpOperand &operand : child->getOpOperands()) {
+      if (!condition(operand))
+        return WalkResult::interrupt();
+    }
+    return WalkResult::advance();
+  };
+  return op->walk(walkFn).wasInterrupted();
+}
+
+static bool dependsOnGuarded(Operation *op,
+                             function_ref<bool(Value)> definedOutsideGuard) {
+  return dependsOnGuarded(op, [&](OpOperand &operand) {
+    return definedOutsideGuard(operand.get());
+  });
+}
+
+static bool loopSideEffectFreeOrHasOnlyReadEffect(Operation *loop) {
+  for (auto &region : loop->getRegions()) {
+    for (auto &block : region.getBlocks()) {
+      for (Operation &op : block.getOperations()) {
+        if (!isMemoryEffectFree(&op) && !hasOnlyReadEffect(&op))
+          return false;
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cxy-1993 wrote:

function 'hasOnlyReadEffect' doesn't consider recursive effect...

https://github.com/llvm/llvm-project/pull/120302