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__builtin_expect vs inlining
- To: Ivan Kokshaysky <ink at jurassic dot park dot msu dot ru>
- Subject: __builtin_expect vs inlining
- From: Richard Henderson <rth at twiddle dot net>
- Date: Sat, 5 May 2001 10:06:35 -0700
- Cc: linux-kernel at vger dot kernel dot org, gcc-patches at gcc dot gnu dot org
- References: <20010503194747.A552@jurassic.park.msu.ru> <20010504141318.B11122@twiddle.net> <20010505181718.B2302@jurassic.park.msu.ru>
On Sat, May 05, 2001 at 06:17:18PM +0400, Ivan Kokshaysky wrote:
> > Eh? Would you give me an example that isn't working properly?
>
> Sure.
Fixed thus.
> So one of the questions: can one rely on current branch predictions
> algorithms (val < 0, val = 0 false etc.) in the long term?
Err, no. We reserve the right to tweek the predictions, or to replace
them with different heuristics. I'd hope they'd be _generally_ better
heuristics, though the effect on any one particular test might change.
r~
* integrate.c (copy_insn_list): Substitute NOTE_EXPECTED_VALUE.
Index: integrate.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/integrate.c,v
retrieving revision 1.142
diff -c -p -r1.142 integrate.c
*** integrate.c 2001/05/03 16:14:34 1.142
--- integrate.c 2001/05/05 16:54:24
*************** copy_insn_list (insns, map, static_chain
*** 1536,1541 ****
--- 1536,1546 ----
else
NOTE_BLOCK (copy) = *mapped_block_p;
}
+ else if (copy
+ && NOTE_LINE_NUMBER (copy) == NOTE_INSN_EXPECTED_VALUE)
+ NOTE_EXPECTED_VALUE (copy)
+ = copy_rtx_and_substitute (NOTE_EXPECTED_VALUE (insn),
+ map, 0);
}
else
copy = 0;