[Mlir-commits] [mlir] [mlir][SCF] Modernize `coalesceLoops` method to handle `scf.for` loops with iter_args (PR #87019)

[Oleksandr Alex Zinenko]

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@@ -4532,6 +4532,42 @@ LogicalResult AffineDelinearizeIndexOp::verify() {
   return success();
 }
 
+namespace {
+// When outer dimension used for delinearization are ones, the corresponding
+// results can all be replaced by zeros.
+struct DropUnitOuterDelinearizeDims
+    : public OpRewritePattern<AffineDelinearizeIndexOp> {
+  using OpRewritePattern::OpRewritePattern;
+
+  LogicalResult matchAndRewrite(AffineDelinearizeIndexOp indexOp,
+                                PatternRewriter &rewriter) const override {
+    ValueRange basis = indexOp.getBasis();
+    if (basis.empty()) {
+      return failure();
+    }
+    std::optional<int64_t> basisValue =
+        getConstantIntValue(getAsOpFoldResult(basis.front()));
+    if (!basisValue || basisValue != 1) {
+      return failure();
+    }
+    SmallVector<Value> replacements;
+    Location loc = indexOp.getLoc();
+    replacements.push_back(rewriter.create<arith::ConstantIndexOp>(loc, 0));
+    auto newIndexOp = rewriter.create<AffineDelinearizeIndexOp>(
+        loc, indexOp.getLinearIndex(), basis.drop_front());
+    replacements.append(newIndexOp->result_begin(), newIndexOp->result_end());
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ftynse wrote:

Nit: llvm::append_range.

https://github.com/llvm/llvm-project/pull/87019