https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104986
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Andrew Macleod from comment #5) > Looking at the strlen1 output, it only ever asks ranger about 6 names: > > 334 range_of_expr(_36) at stmt _52 = iftmp.1_17 + _36; > TRUE : (334) range_of_expr (_36) sizetype [3, 5] > maybe_invalidate called for *_52 = _60; > maybe_invalidate returns 1 > 342 range_of_expr(_69) at stmt _71 = iftmp.1_7 + _69; > TRUE : (342) range_of_expr (_69) sizetype [3, 5] > maybe_invalidate called for *_71 = _72; > maybe_invalidate returns 1 > 348 range_of_expr(_6) at stmt _31 = iftmp.1_76 + _6; > TRUE : (348) range_of_expr (_6) sizetype [2, 4] > maybe_invalidate called for *_31 = _32; > maybe_invalidate returns 1 > 367 range_of_expr(_37) at stmt _39 = iftmp.1_76 + _37; > TRUE : (367) range_of_expr (_37) sizetype [1, 3] > maybe_invalidate called for *_39 = _40; > statement may clobber object _31 0 bytes in size > > maybe_invalidate returns 1 > 375 range_of_expr(_45) at stmt _47 = iftmp.1_76 + _45; > TRUE : (375) range_of_expr (_45) sizetype [0, 2] > maybe_invalidate called for *_47 = _48; > statement may clobber object _39 0 bytes in size > maybe_invalidate returns 1 > 383 range_of_expr(_53) at stmt _55 = iftmp.1_76 + _53; > TRUE : (383) range_of_expr (_53) sizetype [1, 1] So maybe strlen can invoke ranger on GIMPLE_CONDs to mark unreachable code on the fly? IIRC domwalk has some ability to skip not executable edges so if the walk makes sure to properly initialize that for outgoing edges it might work in that it would refrain from optimizing/diagnosing in unreachable regions. > Is there a reason it runs before vrp2? Likely historical or the idea that VRP can do something with its results, like propagate constants (but there's now a CCP pass after it).
