[llvm-dev] Possible soundness issue with available_externally (split from "RFC: Add guard intrinsics")

Sanjoy Das via llvm-dev llvm-dev at lists.llvm.org
Mon Feb 29 10:51:14 PST 2016

On Mon, Feb 29, 2016 at 8:21 AM, Sanjoy Das
<sanjoy at playingwithpointers.com> wrote:
> On Sat, Feb 27, 2016 at 1:41 PM, Sanjoy Das
> <sanjoy at playingwithpointers.com> wrote:
>> Just as a reality check, I wrote up a demonstration where one link
>> order causes a SIGFPE and another doesn't (and the program is well
>> defined, as far as I can tell).  All TUs are compiled with -O3.  This is also
>> an instance where we don't actually speculate an inline function, but only
>> DSE across it (after deducing readnone).
>> Here's the link https://github.com/sanjoy/comdat-ipo
> This test case "works" with gcc 5.3.0 too, afaict.

I should have been clearer here -- by the above I meant gcc also
miscompiles the program in the same way.

-- Sanjoy

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