[clang] [CIR] Add support for array constructors (PR #149142)

[Andy Kaylor via cfe-commits]

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@@ -22,15 +24,97 @@ struct LoweringPreparePass : public LoweringPrepareBase<LoweringPreparePass> {
   void runOnOperation() override;
 
   void runOnOp(Operation *op);
+  void lowerArrayCtor(ArrayCtor op);
 };
 
 } // namespace
 
-void LoweringPreparePass::runOnOp(Operation *op) {}
+void LoweringPreparePass::runOnOp(Operation *op) {
+  if (auto arrayCtor = dyn_cast<ArrayCtor>(op)) {
+    lowerArrayCtor(arrayCtor);
+  }
+}
+
+static void lowerArrayDtorCtorIntoLoop(CIRBaseBuilderTy &builder,
+                                       mlir::Operation *op, mlir::Type eltTy,
+                                       mlir::Value arrayAddr,
+                                       uint64_t arrayLen) {
+  // Generate loop to call into ctor/dtor for every element.
+  Location loc = op->getLoc();
+
+  // TODO: instead of fixed integer size, create alias for PtrDiffTy and unify
+  // with CIRGen stuff.
+  auto ptrDiffTy =
+      cir::IntType::get(builder.getContext(), 64, /*isSigned=*/false);
+  auto numArrayElementsConst = builder.create<cir::ConstantOp>(
+      loc, ptrDiffTy, cir::IntAttr::get(ptrDiffTy, arrayLen));
+
+  auto begin = builder.create<cir::CastOp>(
+      loc, eltTy, cir::CastKind::array_to_ptrdecay, arrayAddr);
+  mlir::Value end = builder.create<cir::PtrStrideOp>(loc, eltTy, begin,
+                                                     numArrayElementsConst);
+
+  mlir::Value tmpAddr = builder.createAlloca(
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andykaylor wrote:

As we discussed, I think this is OK as it is.

https://github.com/llvm/llvm-project/pull/149142