[Mlir-commits] [mlir] [mlir][SCF] Add folding for IndexSwitchOp (PR #70924)

[llvmlistbot at llvm.org]

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@@ -4166,6 +4166,33 @@ void IndexSwitchOp::getRegionInvocationBounds(
     bounds.emplace_back(/*lb=*/0, /*ub=*/i == liveIndex);
 }
 
+LogicalResult IndexSwitchOp::fold(FoldAdaptor adaptor,
+                                  SmallVectorImpl<OpFoldResult> &results) {
+  std::optional<int64_t> maybeCst = getConstantIntValue(getArg());
+  if (!maybeCst.has_value())
+    return failure();
+  int64_t cst = *maybeCst;
+  int64_t caseIdx, e = getNumCases();
+  for (caseIdx = 0; caseIdx < e; ++caseIdx) {
+    if (cst == getCases()[caseIdx])
+      break;
+  }
+
+  Region &r = (caseIdx < getNumCases()) ? getCaseRegions()[caseIdx]
+                                        : getDefaultRegion();
+  Block &source = r.front();
+  results.assign(source.getTerminator()->getOperands().begin(),
+                 source.getTerminator()->getOperands().end());
+
+  Block *pDestination = (*this)->getBlock();
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qcolombet wrote:

Is it possible to have a dandling `IndexSwitchOp`?
I.e., can pDestination be `nullptr`?

https://github.com/llvm/llvm-project/pull/70924