------- Comment #2 from burnus at gcc dot gnu dot org 2010-08-18 17:44 ------- (In reply to comment #1) > (In reply to comment #0) > > In some cases, one might need to check for the unsave_math_optimization flag > > before changing, e.g., "2+(a-2)" to "a" - or rather "(a)". > > The whole point of PAREN_EXPR in the middle-end is to avoid transforming > 2 + (a - 2) even _with_ -funsafe-math-optimizations / -ffast-math!
Well, I am talking about FE optimizations with -fno-protect-parens (note the "no-"). The PAREN_EXPR protection *is* and *should* one done with -fprotect-parens (which is the default setting). In terms of the middle end, -fno-protect-parens and -fprotect-parens are both properly handled. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45318
