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Re: [RFC] asm goto
- From: Richard Henderson <rth at redhat dot com>
- To: Adam Nemet <anemet at caviumnetworks dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, jbaron at redhat dot com
- Date: Mon, 27 Jul 2009 15:39:38 -0700
- Subject: Re: [RFC] asm goto
- References: <4A6E1BE6.firstname.lastname@example.org> <email@example.com>
On 07/27/2009 03:29 PM, Adam Nemet wrote:
Isn't the prediction logic a little too subtle here? I.e. the fact that
We assume that bb0->bb2 is more likely than bb0->bb1? Is this BTW a
heuristic we already have? PRED_GOTO maybe?
A heuristic that minimizes the number of jumps will order the blocks
properly, given that it can neither remove nor invert the asm goto jump.
That said, I have an additional plan for
that will affect the prediction logic such that the BB beginning with L1
should be put into the .text.unlikely section (if supported), and edges
to this label should be considered very unlikely.
But let's keep the two issues separate here.