Use spill cache for more ops and allow opt-out.

Author: fzi-hielscher

include/circt/Conversion/HWToLLVM.h

@@ -67,10 +67,7 @@ void populateHWToLLVMConversionPatterns(
     Namespace &globals,
     DenseMap<std::pair<Type, ArrayAttr>, mlir::LLVM::GlobalOp>
         &constAggregateGlobalsMap,
-    ArraySpillCache &spillCache);
-
-/// Create an HW to LLVM conversion pass.
-std::unique_ptr<OperationPass<ModuleOp>> createConvertHWToLLVMPass();
+    std::optional<ArraySpillCache> &spillCacheOpt);
 
 } // namespace circt
 

include/circt/Conversion/Passes.td

@@ -509,7 +509,10 @@ def ConvertHWToLLVM : Pass<"convert-hw-to-llvm", "mlir::ModuleOp"> {
   let description = [{
     This pass translates HW to LLVM.
   }];
-  let constructor = "circt::createConvertHWToLLVMPass()";
+  let options = [Option<
+      "spillArraysEarly", "spill-arrays-early", "bool", "true",
+      "If true, array values will me materialized on the stack at the"
+      "point of definition. This can reduce redundant stack allocations.">];
   let dependentDialects = ["mlir::LLVM::LLVMDialect"];
 }
 

lib/Conversion/ArcToLLVM/LowerArcToLLVM.cpp

@@ -761,13 +761,13 @@ void LowerArcToLLVMPass::runOnOperation() {
   // CIRCT patterns.
   DenseMap<std::pair<Type, ArrayAttr>, LLVM::GlobalOp> constAggregateGlobalsMap;
   populateHWToLLVMTypeConversions(converter);
-  ArraySpillCache spillCache;
+  std::optional<ArraySpillCache> spillCacheOpt = ArraySpillCache();
   {
     OpBuilder spillBuilder(getOperation());
-    spillCache.spillNonHWOps(spillBuilder, converter, getOperation());
+    spillCacheOpt->spillNonHWOps(spillBuilder, converter, getOperation());
   }
   populateHWToLLVMConversionPatterns(converter, patterns, globals,
-                                     constAggregateGlobalsMap, spillCache);
+                                     constAggregateGlobalsMap, spillCacheOpt);
 
   populateCombToArithConversionPatterns(converter, patterns);
   populateCombToLLVMConversionPatterns(converter, patterns);