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Re: [tree-ssa] Removing redundant loads
- From: law at redhat dot com
- To: Jason Merrill <jason at redhat dot com>
- Cc: Diego Novillo <dnovillo at redhat dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 30 May 2003 18:10:32 -0600
- Subject: Re: [tree-ssa] Removing redundant loads
- Reply-to: law at redhat dot com
In message <wvln0h40yjy.fsf@prospero.boston.redhat.com>, Jason Merrill writes:
>On Fri, 30 May 2003 16:54:47 -0600, law@redhat.com wrote:
>
>> ARggh.
>>
>> operand_equal_p returns false if either operand has side effects -- even
>> if both operands are equal.
>
>Hmm. This isn't a problem for gimple_tree_eq, since I don't want to share
>a temp between evaluations of an expression with side effects.
Understood.
>> For example, if you pass it this tree for both operands, you'll get a
>> false back from operand_b because this expression has tree_side_effects
>> set.
>
>Why does that expression have TREE_SIDE_EFFECTS set?
Unknown.
Jeff