Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On October 28, 2017 2:53:56 PM GMT+02:00, Marc Glisse wrote: > >I am sending the new version of the patch in a separate email, to make >it >more visible, and only replying to a few points here. > >On Thu, 19 Oct 2017, Richard Biener wrote: > >> On Mon, Oct 9, 2017 at 12:55

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

I am sending the new version of the patch in a separate email, to make it more visible, and only replying to a few points here. On Thu, 19 Oct 2017, Richard Biener wrote: On Mon, Oct 9, 2017 at 12:55 PM, Marc Glisse wrote: On Mon, 3 Jul 2017, Richard Biener wrote:

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Mon, Oct 9, 2017 at 12:55 PM, Marc Glisse wrote: > On Mon, 3 Jul 2017, Richard Biener wrote: > >> On Sat, 1 Jul 2017, Marc Glisse wrote: >> >>> I wrote a quick prototype to see what the fallout would look like. >>> Surprisingly, it actually passes bootstrap+testsuite on

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Mon, 3 Jul 2017, Richard Biener wrote: On Sat, 1 Jul 2017, Marc Glisse wrote: I wrote a quick prototype to see what the fallout would look like. Surprisingly, it actually passes bootstrap+testsuite on ppc64el with all languages with no regression. Sure, it is probably not a complete

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Sat, 1 Jul 2017, Marc Glisse wrote: > On Thu, 22 Jun 2017, Richard Biener wrote: > > > On Thu, 22 Jun 2017, Marc Glisse wrote: > > > > > On Thu, 22 Jun 2017, Richard Biener wrote: > > > > > > > > If we consider pointers as unsigned, with a subtraction that has a > > > > > signed > > > > >

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Thu, 22 Jun 2017, Richard Biener wrote: On Thu, 22 Jun 2017, Marc Glisse wrote: On Thu, 22 Jun 2017, Richard Biener wrote: If we consider pointers as unsigned, with a subtraction that has a signed result with the constraint that overflow is undefined, we cannot model that optimally with

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Thu, 22 Jun 2017, Marc Glisse wrote: > On Thu, 22 Jun 2017, Richard Biener wrote: > > > > If we consider pointers as unsigned, with a subtraction that has a signed > > > result with the constraint that overflow is undefined, we cannot model > > > that > > > optimally with just the usual

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Thu, 22 Jun 2017, Richard Biener wrote: If we consider pointers as unsigned, with a subtraction that has a signed result with the constraint that overflow is undefined, we cannot model that optimally with just the usual signed/unsigned operations, so I am in favor of POINTER_DIFF, at least

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Wed, 21 Jun 2017, Marc Glisse wrote: > On Wed, 21 Jun 2017, Jakub Jelinek wrote: > > > So, I wrote following patch to do the subtraction in unsigned > > type. It passes bootstrap, but on both x86_64-linux and i686-linux > > regresses: > > +FAIL: gcc.dg/torture/pr66178.c -O* (test for

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Wed, 21 Jun 2017, Jakub Jelinek wrote: So, I wrote following patch to do the subtraction in unsigned type. It passes bootstrap, but on both x86_64-linux and i686-linux regresses: +FAIL: gcc.dg/torture/pr66178.c -O* (test for excess errors) +FAIL: gcc.dg/tree-ssa/cmpexactdiv-2.c

Re: [RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Wed, Jun 21, 2017 at 04:40:01PM +0200, Jakub Jelinek wrote: > So, I wrote following patch to do the subtraction in unsigned > type. It passes bootstrap, but on both x86_64-linux and i686-linux > regresses: > +FAIL: gcc.dg/torture/pr66178.c -O* (test for excess errors) > +FAIL:

[RFC PATCH] Fix pointer diff (was: -fsanitize=pointer-overflow support (PR sanitizer/80998))

On Tue, Jun 20, 2017 at 10:18:20AM +0200, Richard Biener wrote: > > > > 3) not really related to this patch, but something I also saw during the > > > > bootstrap-ubsan on i686-linux: > > > > ../../gcc/bitmap.c:141:12: runtime error: signed integer overflow: > > > > -2147426384 - 2147475412