[LLVMdev] RegAllocFast uses too much stack
echristo at apple.com
Mon Jul 11 15:43:21 PDT 2011
On Jul 11, 2011, at 3:41 PM, Dan Gohman wrote:
> On Jul 11, 2011, at 3:06 PM, Eli Friedman wrote:
>> On Mon, Jul 11, 2011 at 2:44 PM, Eric Christopher <echristo at apple.com> wrote:
>>> On Jul 11, 2011, at 1:48 PM, Nick Lewycky wrote:
>>> This seems odd. I'd think that fast-isel should be able to materialize the constants when we want them rather than at the beginning of the block.
>> I'm not entirely sure why, but FastISel does intentionally materialize
>> constants at the beginning of the block. See
>> FastISel::enterLocalValueArea etc. Maybe Dan knows why?
> Going bottom-up, FastISel doesn't know when it'll see the first use of a value
> in a block. Cleverer schemes are possible.
Or less clever by not caching the result? :)
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