Fixing nondeterminism in pattern application.

The ReduceRegion* patterns are matching on the same ops as the PointwiseToLinalg*
patterns and on certain toolchains (MSVC) the order can be wrong. If the pointwise
runs first then it converts the op *within* the reduction before the reduction one
runs, leading to nested linalg op weirdness.

PiperOrigin-RevId: 373848269

lib/Dialect/mhlo/transforms/legalize_to_linalg.cc

@@ -2354,7 +2354,8 @@ void populateHLOToLinalgConversionPattern(MLIRContext* context,
                    ReduceRegionXLAOpConversion<mhlo::OrOp>,
                    ReduceRegionXLAOpConversion<mhlo::SelectOp>,
                    ReduceRegionXLAOpConversion<mhlo::CompareOp>,
-                   ReduceRegionReturnOpConversion>(context);
+                   ReduceRegionReturnOpConversion>(context,
+                                                   PatternBenefit(1000));
 }
 
 std::unique_ptr<OperationPass<FuncOp>> createLegalizeHloToLinalgPass() {