RE: Do we need to do anything about "dead µops?"

[David Laight]

From: Josh Poimboeuf
> Sent: 04 May 2021 04:16
...
> I was actually thinking more along the lines of
> 
> 	val = 0;
> 
> 	if (user_supplied_idx < ARRAY_SIZE) // trained to speculatively be 'true'
> 		val = boring_non_secret_array[user_supplied_idx];
> 
> 	if (val & 1)
> 		do_something();
> 
> In other words, the victim code wouldn't be accessing the secret
> intentionally.  So there's no reason for it to avoid doing
> data-dependent branches.

Isn't that one of the very boring standard spectre cases?

	David

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