<!-- https://go.dev/issue/62737 , https://golang.org/cl/576681,  https://golang.org/cl/577615 -->
The compiler in Go 1.23 can now overlap the stack frame slots of local variables
accessed in disjoint regions of a function, which reduces stack usage
for Go applications.

<!-- https://go.dev/cl/577935 -->
For 386 and amd64, the compiler will use information from PGO to align certain

	"os"
	"unsafe"
)

func isExecutable(protection int32) bool {
	return (protection&_VM_PROT_EXECUTE) != 0 && (protection&_VM_PROT_READ) != 0
}

// machVMInfo uses the mach_vm_region region system call to add mapping entries
// for the text region of the running process.
func machVMInfo(addMapping func(lo, hi, offset uint64, file, buildID string)) bool {
	added := false
	var addr uint64 = 0x1
	for {
		var memRegionSize uint64

	ctx, t = trace.NewTask(ctx, "do")
	defer t.End()

	trace.Log(ctx, "log2", "do")

	// Create a region and spawn more tasks and more workers.
	trace.WithRegion(ctx, "fanout", func() {
		for i := 0; i < k; i++ {
			go func(i int) {
				trace.WithRegion(ctx, fmt.Sprintf("region%d", i), func() {
					trace.Logf(ctx, "log", "fanout region%d", i)
					if i == 2 {
						do(ctx, 0)
						return
					}
				})
			}(i)
		}
	})

  }
};

}  // namespace

// Inserts call to the given function into the 'region'.
void CreateRegionWithCall(func::FuncOp func, Region& region, Location loc) {
  OpBuilder builder(region);
  auto block = builder.createBlock(&region);
  SmallVector<Value, 4> new_operands;
  for (Type t : func.getFunctionType().getInputs())
    new_operands.push_back(block->addArgument(t, loc));

</ul>

<h2>User-defined tasks and regions</h2>
<p>
  The trace API allows a target program to annotate a <a
  href='https://pkg.go.dev/runtime/trace#Region'>region</a> of code
  within a goroutine, such as a key function, so that its performance
  can be analyzed.

  <a href='https://pkg.go.dev/runtime/trace#Log'>Log events</a> may be
  associated with a region to record progress and relevant values.

    // collect effects for all ops in the regions instead of collecting effects
    // for the op itself. This is important to avoid conservatism and to find
    // resource variable accesses in regions which are not exposed to the op
    // interface.
    for (Region& region : op->getRegions()) {
      for (Operation& region_op : region.front().without_terminator()) {

    OptionalAttr<DictArrayAttr>:$res_attrs
  );

  let results = (outs);

  // When the regions is empty, the tfr.func is an external function and used
  // to model the element type constraints of the tf op. Otherwise, there is one
  // region containing the composition.
  let regions = (region VariadicRegion<AnyRegion>:$body);

  let skipDefaultBuilders = 1;

  let builders = [

        }
        // Transfer the annotation to both region arguments
        for (Region* region : while_region.getRegions()) {
          BlockArgument arg = region->getArgument(output_index);
          LLVM_DEBUG(llvm::dbgs()
                     << "  Propagating device = '" << *device << "' to arg #"
                     << output_index << " of region #"
                     << region->getRegionNumber() << "\n");

    if (!parent_op) continue;
    builder.setInsertionPoint(parent_op);

    // Recreate the operation by using the wrapper's operands and return types.
    // TODO(fengliuai): copy the regions.
    OperationState state(op->getLoc(), op->getName().getStringRef(),
                         parent_op->getOperands(), parent_op->getResultTypes(),
                         op->getAttrs(), op->getSuccessors());

	scr, err := ParseScript(s)
	if err != nil {
		panic(err)
	}
	return scr
}

// MustParseRegion is like ParseRegion, but panics if the given region cannot be
// parsed. It simplifies safe initialization of Region values.
func MustParseRegion(s string) Region {
	r, err := ParseRegion(s)
	if err != nil {
		panic(err)
	}
	return r
}

var (
	und = Tag{}

	Und Tag = Tag{}