On Fri, 15 Nov 2013, Kenneth Zadeck wrote: > > This patch fixes a number of places where the mode bitsize had been used but > the mode precision should have been used. The tree level is somewhat sloppy > about this - some places use the mode precision and some use the mode bitsize. > It seems that the mode precision is the proper choice since it does the > correct thing if the underlying mode is a partial int mode. > > This code has been tested on x86-64 with no regressions. Ok to commit?
Ok. Thanks, Richard. > > > 2013-11-15 Kenneth Zadeck <zad...@naturalbridge.com> > * tree.c (int_fits_type_p): Change GET_MODE_BITSIZE to > GET_MODE_PRECISION. > * fold-const.c (fold_single_bit_test_into_sign_test, > fold_binary_loc): Change GET_MODE_BITSIZE to > GET_MODE_PRECISION. > > Kenny > > > On 11/15/2013 08:32 AM, Kenneth Zadeck wrote: > > On 11/15/2013 04:07 AM, Eric Botcazou wrote: > > > > this code from fold-const.c starts on line 13811. > > > > > > > > else if (TREE_INT_CST_HIGH (arg1) == signed_max_hi > > > > && TREE_INT_CST_LOW (arg1) == signed_max_lo > > > > && TYPE_UNSIGNED (arg1_type) > > > > /* We will flip the signedness of the comparison operator > > > > associated with the mode of arg1, so the sign bit is > > > > specified by this mode. Check that arg1 is the signed > > > > max associated with this sign bit. */ > > > > && width == GET_MODE_BITSIZE (TYPE_MODE (arg1_type)) > > > > /* signed_type does not work on pointer types. */ > > > > && INTEGRAL_TYPE_P (arg1_type)) > > > with width defined as: > > > > > > unsigned int width = TYPE_PRECISION (arg1_type); > > > > > > > it seems that the check on bitsize should really be a check on the > > > > precision of the variable. If this seems right, i will correct this on > > > > the trunk and make the appropriate changes to the wide-int branch. > > > Do you mean > > > > > > && width == GET_MODE_PRECISION (TYPE_MODE (arg1_type)) > > > > > > instead? If so, that would probably make sense, but there are a few other > > > places with the same TYPE_PRECISION/GET_MODE_BITSIZE check, in particular > > > the > > > very similar transformation done in fold_single_bit_test_into_sign_test. > > > > > yes. I understand the need to do this check on the mode rather than the > > precision of the type itself. > > The point is that if the mode under this type happens to be a partial int > > mode, then that sign bit may not even be where the bitsize points to. > > > > However, having just done a few greps, it looks like this case was just the > > one that i found while doing the wide-int work, there may be several more of > > these cases. Just in fold-const, there are a couple in fold_binary_loc. > > The one in tree.c:int_fits_type_p looks particularly wrong. > > > > I think that there are also several in tree-vect-patterns.c. > > > > Kenny > > -- Richard Biener <rguent...@suse.de> SUSE / SUSE Labs SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746 GF: Jeff Hawn, Jennifer Guild, Felix Imend"orffer
