[Bug tree-optimization/111668] [12/13/14 Regression] vrp2 (match and simplify) introduces invalid wide signed Boolean values
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111668 --- Comment #6 from CVS Commits --- The master branch has been updated by Jakub Jelinek : https://gcc.gnu.org/g:7ab01269396203d5200fff8579768da54dcfde5d commit r14-4391-g7ab01269396203d5200fff8579768da54dcfde5d Author: Jakub Jelinek Date: Wed Oct 4 09:27:40 2023 +0200 match.pd: Fix up a ? cst1 : cst2 regression on signed bool [PR111668] My relatively recent changes to these simplifiers to avoid doing build_nonstandard_integer_type (primarily for BITINT_TYPE) broke PR111668, a recurrence of the PR110487 bug. I thought the build_nonstandard_integer_type isn't ever needed there, but there is one special case where it is. For the a ? -1 : 0 and a ? 0 : -1 simplifications there are actually 3 different cases. One is for signed 1-bit precision types (signed kind of implied from integer_all_onesp, because otherwise it would match integer_onep earlier), where the simplifier wierdly was matching them using the a ? powerof2cst : 0 -> a << (log2(powerof2cst)) simplification and then another simplifier optimizing away the left shift when log2(powerof2cst) was 0. Another one is signed BOOLEAN_TYPE with precision > 1, where indeed we shouldn't be doing the negation in type, because it isn't well defined in that type, the type only has 2 valid values, 0 and -1. As an alternative, we could also e.g. cast to signed 1-bit precision BOOLEAN_TYPE and then extend to type. And the last case is what we were doing for types which have both 1 and -1 (all all ones) as valid values (i.e. all signed/unsigned ENUMERAL_TYPEs, INTEGRAL_TYPEs and BITINT_TYPEs with precision > 1). The following patch avoids the hops through << 0 for 1-bit precision and uses build_nonstandard_integer_type solely for the BOOLEAN_TYPE types (where we have a guarantee the precision is reasonably small, nothing ought to be created 129+ bit precision BOOLEAN_TYPEs). 2023-10-04 Jakub Jelinek PR tree-optimization/111668 * match.pd (a ? CST1 : CST2): Handle the a ? -1 : 0 and a ? 0 : -1 cases before the powerof2cst cases and differentiate between 1-bit precision types, larger precision boolean types and other integral types. Fix comment pastos and formatting.
[Bug tree-optimization/111668] [12/13/14 Regression] vrp2 (match and simplify) introduces invalid wide signed Boolean values
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111668 Jakub Jelinek changed: What|Removed |Added Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |jakub at gcc dot gnu.org --- Comment #5 from Jakub Jelinek --- Created attachment 56033 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56033=edit gcc14-pr111668.patch Untested fix which avoids jumping through << 0 and uses the negations for the larger precision signed boolean cases.
[Bug tree-optimization/111668] [12/13/14 Regression] vrp2 (match and simplify) introduces invalid wide signed Boolean values
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111668
--- Comment #4 from Jakub Jelinek ---
So, for the a ? -1 : 0 case (and similarly for a ? 0 : -1) we have 3 distinct
cases.
One is signed 1-bit precision type, for which we jump through the unnecessary
hops of
trying to optimize e.g. the first one as (lshift (convert:type
(convert:boolean_type_node @0) { integer_zero_node; }) and then optimizing away
the shift. Then the signed boolean case of larger precision, where we can
choose what
exactly we want it to simplify to, one is the negation in signed integer type
of the same precision and another one would be to cast to signed boolean type
rather than unsigned. And finally the case where both 1 and -1 are valid,
where we should use the negation.
If we go the negation route for the second subcase, that is the only case where
we need build_nonstandard_integer_type. If we go with the casts, we don't need
it anywhere.
[Bug tree-optimization/111668] [12/13/14 Regression] vrp2 (match and simplify) introduces invalid wide signed Boolean values
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111668 Andrew Pinski changed: What|Removed |Added Target Milestone|--- |14.0 Summary|vrp2 (match and simplify) |[12/13/14 Regression] vrp2 |introduces invalid wide |(match and simplify) |signed Boolean values |introduces invalid wide ||signed Boolean values --- Comment #3 from Andrew Pinski --- Since PR 110487 is a regression, this is a regression.
