------- Comment #4 from rguenther at suse dot de 2009-11-18 16:51 ------- Subject: Re: flag_gtoggle in free_lang_data hides -fcompare-debug errors
On Wed, 18 Nov 2009, aoliva at gcc dot gnu dot org wrote: > ------- Comment #3 from aoliva at gcc dot gnu dot org 2009-11-18 16:30 > ------- > Different UIDs affect hash table walks, which in turn may affect codegen. > We've had several -g/-g0 codegen differences ultimately caused by decl UID > differences, and they were detected and fixed long before -fcompare-debug was > even introduced, i.e., they were detected with the compare-debug script that > compares actual generated code. > > That's why -fcompare-debug must report such differences. Even if the code > ends > up the same in one particular testcase, supersets of that testcase would > likely > diverge. Disregarding the UIDs in -fcompare-debug would hide errors. Sorry, but hashtable walks are always broken if codegen depends on them and you do not ensure proper ordering. Enforcing same UIDs for -g/-g0 just forces us to use more memory than necessary. Richard. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42088