Re: [pypy-dev] [pypy-svn] r77101 - in pypy/trunk/pypy: jit/tl module/__builtin__ module/__builtin__/test module/pypyjit/test
Hi, On 16/09/10 07:27, hakanardo@codespeak.net wrote:
Log: Allow jit to unroll calls to max() and min() with more than one argument.
[cut]
+@unroll_safe @specialize.arg(2) def min_max(space, args, implementation_of): if implementation_of == "max": compare = space.gt else: compare = space.lt + + args_w = args.arguments_w + if len(args_w)> 1 and not args.keywords: # Unrollable case + w_max_item = None + for w_item in args_w: + if w_max_item is None or \ + space.is_true(compare(w_item, w_max_item)): + w_max_item = w_item + return w_max_item + else: + return min_max_loop(space, args, implementation_of)
I don't think it's a good idea. What happens if I call max() over a list of 1 million of elements? We obviously don't want the jit to unroll 1 million of iterations. Or am I missing something? ciao, Anto
2010 at 9:03 AM, Antonio Cuni
+ + args_w = args.arguments_w + if len(args_w)> 1 and not args.keywords: # Unrollable case + w_max_item = None + for w_item in args_w: + if w_max_item is None or \ + space.is_true(compare(w_item, w_max_item)): + w_max_item = w_item + return w_max_item + else: + return min_max_loop(space, args, implementation_of)
I don't think it's a good idea. What happens if I call max() over a list of 1 million of elements? We obviously don't want the jit to unroll 1 million of iterations. Or am I missing something?
If lst is your list, the call max(lst) has a single argument, the list, and it will be passed to the old implementation now called min_max_loop. However if you call max(*lst) the jit will unroll it. But why would you do that? The idea here was to optimize the case max(i,0) where you typically only have a few arguments. Anyway, how about calling min_max_loop() as soon as len(args_w) > 10 to be on the safe side? -- Håkan Ardö
Hi, Can you maybe make a branch, and move the checkin on the branch? That's the kind of change that needs careful consideration... Armin
participants (3)
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Antonio Cuni -
Armin Rigo -
Hakan Ardo