[llvm-commits] [llvm] r49610 - in /llvm/trunk/test/Analysis/BasicAA: const-dce.ll pure-const-dce.ll

[Owen Anderson]

On Apr 14, 2008, at 7:37 PM, Daniel Berlin wrote:

> On Mon, Apr 14, 2008 at 4:24 PM, Dan Gohman <gohman at apple.com> wrote:
>>
>>
>> It looks like the test was testing that two calls with identical
>> arguments to a readonly function with no intervening stores can
>> be changed to one call. What's horribly unsafe about that?
>
> I don't see anything  unsafe about that either, even though readonly
> calls can throw exceptions (since they can only depend on arguments
> and global variables, if the first doesn't throw an exception, and
> there are no stores/etc, the second can't)

The particular testcase wasn't broken, rather GVN's general  
functionality for removing read-only calls.  It wasn't doing the  
appropriate checking for intervening stores to globals.

--Owen
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