------- Comment #9 from rguenther at suse dot de 2009-01-27 12:29 ------- Subject: Re: [4.2/4.3/4.4 Regression] NULL pointers always considered distinct by PTA, even with -fno-delete-null-pointer-checks
On Tue, 27 Jan 2009, bonzini at gnu dot org wrote: > ------- Comment #8 from bonzini at gnu dot org 2009-01-27 12:27 ------- > From PR38985: > > > These passes are able to propagate the address to the load: CCP, VRP, DOM. > > If > > we decide that it's an invalid transformation, fixing them would fix this > > bug. > > The interesting part is that after you disable them... you find out PTA is not > actually able to use the NULL special variable because *NULL and *ANYTHING > conflict! The pointed-to sets are okay though: > > pD.1230_1(D), is dereferenced, its value escapes, points-to anything > nullD.1234_3, is dereferenced, points-to anything, points-to NULL > > The patch in comment #1 however works (tested with -fno-tree-ccp -fno-tree-vrp > -fno-tree-dominator-opts, and looking at the constraints for null). So my > plan > would be: > > 1) apply the patch after regtesting, XFAILing the testcase; > > 2) when PR38985 is fixed, the testcase will pass and the XFAIL will be > removed. > > Sounds okay? Sounds good. Richard. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38984
