Link to issue number:

Closes #17623

Summary of the issue:

As for now, whole-program optimization for eSpeak-NG is intentionally turned off.

# Whole-program optimization causes eSpeak to distort and warble with its Klatt4 voice
# Therefore specifically force it off
"/GL-",

This was introduced in commit cf0443b when MSVC 2012 was used to compile eSpeak.

Enabling whole-program optimization can make the eSpeak DLL more efficient and smaller, from 637 KiB to 624 KiB.

It can also solve the problem of using a dynamically linked version of Sonic without __declspec(dllimport) in the header, because the optimization will be performed by the linker, if whole-program optimization is enabled.

Description of user facing changes

None.

Description of development approach

Enable whole-program optimization by removing the /GL- option.

Testing strategy:

I tried the klatt4 variant, but couldn't notice the difference between enabling and disabling the whole-program optimization. In fact, the waveforms generated are exactly the same.

Known issues with pull request:

None.

Code Review Checklist:

• Documentation:
  • Change log entry
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• API is compatible with existing add-ons.
• Security precautions taken.

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