diff --git a/mlir/lib/Conversion/AsyncToLLVM/AsyncToLLVM.cpp b/mlir/lib/Conversion/AsyncToLLVM/AsyncToLLVM.cpp
--- a/mlir/lib/Conversion/AsyncToLLVM/AsyncToLLVM.cpp
+++ b/mlir/lib/Conversion/AsyncToLLVM/AsyncToLLVM.cpp
@@ -14,6 +14,7 @@
 #include "mlir/Conversion/StandardToLLVM/ConvertStandardToLLVM.h"
 #include "mlir/Dialect/Arithmetic/IR/Arithmetic.h"
 #include "mlir/Dialect/Async/IR/Async.h"
+#include "mlir/Dialect/LLVMIR/FunctionCallUtils.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
 #include "mlir/Dialect/StandardOps/IR/Ops.h"
 #include "mlir/Dialect/StandardOps/Transforms/FuncConversions.h"
@@ -227,37 +228,6 @@
               AsyncAPI::awaitAllAndExecuteFunctionType(ctx));
 }
 
-//===----------------------------------------------------------------------===//
-// Add malloc/free declarations to the module.
-//===----------------------------------------------------------------------===//
-
-static constexpr const char *kMalloc = "malloc";
-static constexpr const char *kFree = "free";
-
-static void addLLVMFuncDecl(ModuleOp module, ImplicitLocOpBuilder &builder,
-                            StringRef name, Type ret, ArrayRef<Type> params) {
-  if (module.lookupSymbol(name))
-    return;
-  Type type = LLVM::LLVMFunctionType::get(ret, params);
-  builder.create<LLVM::LLVMFuncOp>(name, type);
-}
-
-/// Adds malloc/free declarations to the module.
-static void addCRuntimeDeclarations(ModuleOp module) {
-  using namespace mlir::LLVM;
-
-  MLIRContext *ctx = module.getContext();
-  auto builder =
-      ImplicitLocOpBuilder::atBlockEnd(module.getLoc(), module.getBody());
-
-  auto voidTy = LLVMVoidType::get(ctx);
-  auto i64 = IntegerType::get(ctx, 64);
-  auto i8Ptr = LLVMPointerType::get(IntegerType::get(ctx, 8));
-
-  addLLVMFuncDecl(module, builder, kMalloc, i8Ptr, {i64});
-  addLLVMFuncDecl(module, builder, kFree, voidTy, {i8Ptr});
-}
-
 //===----------------------------------------------------------------------===//
 // Coroutine resume function wrapper.
 //===----------------------------------------------------------------------===//
@@ -365,11 +335,18 @@
     // Get coroutine frame size: @llvm.coro.size.i64.
     auto coroSize =
         rewriter.create<LLVM::CoroSizeOp>(loc, rewriter.getI64Type());
+    // The coroutine lowering doesn't properly account for alignment of the
+    // frame, so align everything to 64 bytes which ought to be enough for
+    // everyone. https://llvm.org/PR53148
+    auto coroAlign = rewriter.create<LLVM::ConstantOp>(
+        op->getLoc(), rewriter.getI64Type(), rewriter.getI64IntegerAttr(64));
 
     // Allocate memory for the coroutine frame.
+    auto allocFuncOp = LLVM::lookupOrCreateAlignedAllocFn(
+        op->getParentOfType<ModuleOp>(), rewriter.getI64Type());
     auto coroAlloc = rewriter.create<LLVM::CallOp>(
-        loc, i8Ptr, SymbolRefAttr::get(rewriter.getContext(), kMalloc),
-        ValueRange(coroSize.getResult()));
+        loc, i8Ptr, SymbolRefAttr::get(allocFuncOp),
+        ValueRange{coroAlign, coroSize.getResult()});
 
     // Begin a coroutine: @llvm.coro.begin.
     auto coroId = CoroBeginOpAdaptor(adaptor.getOperands()).id();
@@ -401,9 +378,11 @@
         rewriter.create<LLVM::CoroFreeOp>(loc, i8Ptr, adaptor.getOperands());
 
     // Free the memory.
-    rewriter.replaceOpWithNewOp<LLVM::CallOp>(
-        op, TypeRange(), SymbolRefAttr::get(rewriter.getContext(), kFree),
-        ValueRange(coroMem.getResult()));
+    auto freeFuncOp =
+        LLVM::lookupOrCreateFreeFn(op->getParentOfType<ModuleOp>());
+    rewriter.replaceOpWithNewOp<LLVM::CallOp>(op, TypeRange(),
+                                              SymbolRefAttr::get(freeFuncOp),
+                                              ValueRange(coroMem.getResult()));
 
     return success();
   }
@@ -968,7 +947,6 @@
   // We delay adding the resume function until it's needed because it currently
   // fails to compile unless '-O0' is specified.
   addAsyncRuntimeApiDeclarations(module);
-  addCRuntimeDeclarations(module);
 
   // Lower async.runtime and async.coro operations to Async Runtime API and
   // LLVM coroutine intrinsics.
diff --git a/mlir/test/Conversion/AsyncToLLVM/convert-coro-to-llvm.mlir b/mlir/test/Conversion/AsyncToLLVM/convert-coro-to-llvm.mlir
--- a/mlir/test/Conversion/AsyncToLLVM/convert-coro-to-llvm.mlir
+++ b/mlir/test/Conversion/AsyncToLLVM/convert-coro-to-llvm.mlir
@@ -14,7 +14,8 @@
   // CHECK: %[[ID:.*]] = llvm.intr.coro.id
   %0 = async.coro.id
   // CHECK: %[[SIZE:.*]] = llvm.intr.coro.size : i64
-  // CHECK: %[[ALLOC:.*]] = llvm.call @malloc(%[[SIZE]])
+  // CHECK: %[[ALIGN:.*]] = llvm.mlir.constant(64 : i64) : i64
+  // CHECK: %[[ALLOC:.*]] = llvm.call @aligned_alloc(%[[ALIGN]], %[[SIZE]])
   // CHECK: %[[HDL:.*]] = llvm.intr.coro.begin %[[ID]], %[[ALLOC]]
   %1 = async.coro.begin %0
   return