[mlir] prop-dict printout sometimes starts with `<{`, but sometimes with `< {`

[peledins-zimperium]

This happens, because:

void OpState::genericPrintProperties(OpAsmPrinter &p, Attribute properties,
                                     ArrayRef<StringRef> elidedProps) {
...
if (dictAttr && !elidedProps.empty()) {
...
    if (atLeastOneAttr) {
      p << "<";
      p.printOptionalAttrDict(dictAttr.getValue(), elidedProps); // "< {" - has space
      p << ">";
    }
  } else {
    p << "<" << properties << ">"; // "<{" - no space
  }
...

This depends on whether there are ellided properties being specified in printout or not:
In "< {" case the end result is:

AsmPrinter::Impl::printOptionalAttrDict
...
    // Otherwise, print them all out in braces.
    os << " {"; //// THE SPACE IS COMING FROM HERE
    interleaveComma(filteredAttrs,
                    [&](NamedAttribute attr) { printNamedAttribute(attr); });
    os << '}';

But in other case

void AsmPrinter::Impl::printAttributeImpl(Attribute attr,
                                          AttrTypeElision typeElision) {
  if (!isa<BuiltinDialect>(attr.getDialect())) {
...
  } else if (auto dictAttr = llvm::dyn_cast<DictionaryAttr>(attr)) {
    os << '{';
    interleaveComma(dictAttr.getValue(),
                    [&](NamedAttribute attr) { printNamedAttribute(attr); });
    os << '}';

It would be great to be consistent.

[llvmbot]

@llvm/issue-subscribers-mlir

Author: None (peledins-zimperium)

This happens, because: ``` void OpState::genericPrintProperties(OpAsmPrinter &p, Attribute properties, ArrayRef<StringRef> elidedProps) { ... if (dictAttr && !elidedProps.empty()) { ... if (atLeastOneAttr) { p << "<"; p.printOptionalAttrDict(dictAttr.getValue(), elidedProps); // "< {" - has space p << ">"; } } else { p << "<" << properties << ">"; // "<{" - no space } ... ```

This depends on whether there are ellided properties being specified in printout or not:
In "< {" case the end result is:

AsmPrinter::Impl::printOptionalAttrDict
...
    // Otherwise, print them all out in braces.
    os << " {"; //// THE SPACE IS COMING FROM HERE
    interleaveComma(filteredAttrs,
                    [&](NamedAttribute attr) { printNamedAttribute(attr); });
    os << '}';

But in other case

void AsmPrinter::Impl::printAttributeImpl(Attribute attr,
                                          AttrTypeElision typeElision) {
  if (!isa<BuiltinDialect>(attr.getDialect())) {
...
  } else if (auto dictAttr = llvm::dyn_cast<DictionaryAttr>(attr)) {
    os << '{';
    interleaveComma(dictAttr.getValue(),
                    [&](NamedAttribute attr) { printNamedAttribute(attr); });
    os << '}';

It would be great to be consistent.