Bring MLIR SLP-vectorizer (#7)

Add MLIR SLP vectorizer to test in Wave.

I hope it will eventually go upstream but for now let's keep it there.
llvm/llvm-project#140469


Signed-off-by: Ivan Butygin <[email protected]>

Author: Hardcode84

include/water/Transforms/Passes.td

@@ -38,4 +38,24 @@ def WaterCheckStaticAssertionsPass : Pass<"water-check-static-assertions"> {
   let summary = "Fail if the IR contains a known-false assertion.";
 }
 
+def WaterGreedySLPVectorizer : Pass<"water-greedy-slp-vectorizer"> {
+  let summary = "SLP Vectorizer Pass";
+  let description = [{
+    This pass implements the SLP (Superword Level Parallelism) vectorizer.
+    It detects consecutive operations that can be put together into vector
+    operations. The pass works bi-directionaly, starting from reads or stores,
+    in search of scalars to combine.
+
+    This is greedy vectorizer, it doesn't have any cost model (yet) and it tries
+    to create vector ops if we have at least 2 potential ops.
+  }];
+  let dependentDialects = ["mlir::vector::VectorDialect"];
+
+  let options = [
+    Option<"maxVectorBitwidth", "max-vector-bitwidth", "unsigned",
+      /*default=*/"std::numeric_limits<unsigned>::max()",
+      "Maximum supported vector bitwidth">,
+  ];
+}
+
 #endif // WATER_PASSES

lib/Transforms/CMakeLists.txt

@@ -1,6 +1,7 @@
 add_mlir_dialect_library(MLIRWaterTransforms
   AccessCheckers.cpp
   CheckStaticAssertions.cpp
+  SLPVectorizer.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${PROJECT_SOURCE_DIR}/include/water
@@ -16,6 +17,8 @@ add_mlir_dialect_library(MLIRWaterTransforms
   MLIRIR
   MLIRMemRefDialect
   MLIRPass
+  MLIRRewrite
+  MLIRTransformUtils
   MLIRVectorDialect
   MLIRWaterAnalysis
 )