http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57242
--- Comment #3 from etherice <scottbaldwin at gmail dot com> --- (In reply to Andrew Pinski from comment #1) > This is by design as -g changes the information produced by the front-end > and maybe even predefines too. I think you may have read the report too quickly :) When building the .gch file, and then subsequently building the translation unit that uses the .gch ... even if you do not specify a -gN at all, or specify the SAME -gN (unless both are -g3), the .gch will be ignored when compiling the TU. For example, using -g2 for both (.gch and TU) will cause pch to be ignored. Or using no -g flag at all for both (.gch and TU) will cause pch to be ignored. You MUST specify a -g flag (either -g -g2 or -g3) when building the .gch, and you must specify EXACTLY -g3 when building the TU. I hope that clarifies it.
