[DispatchCreation] Fold extract_slice of broadcast during split reduction tiling (#23012)

This PR moves FoldExtractSliceOfBroadcast to cleanup patterns in
`FormSplitReductionDispatches`. This folds
`extract_slice(broadcast(...))` during tiling rather than in
post-processing. No new lit test is needed as this change reuses an
existing pattern (FoldExtractSliceOfBroadcast) which already has test
coverage.

This relies on an upstream LLVM changes that adds rank-reducing slices
to generatedSlices in replaceExtractSliceWithTiledProducer in
https://github.com/llvm/llvm-project/pull/174248.

ci-extra: test_torch

Signed-off-by: Bangtian Liu <liubangtian@gmail.com>

compiler/src/iree/compiler/DispatchCreation/FormSplitReductionDispatches.cpp

diff --git a/compiler/src/iree/compiler/DispatchCreation/FormSplitReductionDispatches.cpp b/compiler/src/iree/compiler/DispatchCreation/FormSplitReductionDispatches.cpp
index 107ca7c..c8693ae 100644
--- a/compiler/src/iree/compiler/DispatchCreation/FormSplitReductionDispatches.cpp
+++ b/compiler/src/iree/compiler/DispatchCreation/FormSplitReductionDispatches.cpp
@@ -102,16 +102,17 @@
   tileAndFuseOptions.setFusionControlFn(fusionControlFn);
   tileAndFuseOptions.setTilingOptions(std::move(options));
 
+  MLIRContext *context = rewriter.getContext();
+  RewritePatternSet cleanupPatterns(context);
+  populateFoldExtractSliceOfBroadcastPattern(cleanupPatterns);
   if (fusePad) {
-    MLIRContext *context = rewriter.getContext();
-    RewritePatternSet cleanupPatterns(context);
     // When fusing pads we do not want to generate zeroSliceGuards.
     cleanupPatterns.insert<linalg::ExtractSliceOfPadTensorSwapPattern>(
         context,
         [](tensor::ExtractSliceOp) { return /*zeroSliceGuard=*/false; });
-    tileAndFuseOptions.cleanupPatterns =
-        FrozenRewritePatternSet(std::move(cleanupPatterns));
   }
+  tileAndFuseOptions.cleanupPatterns =
+      FrozenRewritePatternSet(std::move(cleanupPatterns));
 
   FailureOr<scf::SCFTileAndFuseResult> result =
       scf::tileConsumerAndFuseProducersUsingSCF(rewriter, op,
@@ -208,7 +209,6 @@
   RewritePatternSet patterns(context);
   linalg::populateSwapExtractSliceWithFillPatterns(patterns);
   tensor::populateMergeConsecutiveInsertExtractSlicePatterns(patterns);
-  populateFoldExtractSliceOfBroadcastPattern(patterns);
   GreedyRewriteConfig config;
   config.setMaxIterations(GreedyRewriteConfig::kNoLimit).enableFolding(true);
   if (failed(applyPatternsGreedily(funcOp, std::move(patterns), config))) {