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Re: [tree-ssa] New type-based aliasing (was: More CFG improvements)
On Thu, 06 Feb 2003, Jeff Law wrote:
> The downside of that is we expose a hell of a lot more objects to the
> PHI insertion routines, which in turn causes 20001226-1.c to blow back
> up :( Luckily, I've got changes here to fix that with better PHI
> insertion.
>
Right. After you enable the pruned form, we can add the bits to
only compute alias sets for stores. Oh BTW, this morning I ran
some Brad Lucier's positively nasty files through tree-ssa. Yum.
The worst one was conform.i with things like:
---------------------------------------------------------
Number of Memory
instances used
---------------------------------------------------------
Referenced variables 5536 21k
....
PHI nodes 157336 6145k
PHI arguments 33400595 254M
---------------------------------------------------------
Total memory used by DFA/SSA data 260M
---------------------------------------------------------
Average number of arguments per PHI node: 212.3 (max: 571)
CFG Stats
---------------------------------------------------------
Number of Memory
instances used
---------------------------------------------------------
Basic blocks 4288 335k
Edges 133673 5221k
Basic block annotations 4288 50k
---------------------------------------------------------
Total memory used by CFG data 5606k
---------------------------------------------------------
Coalesced label blocks: 35 (Max so far: 35)
Coalesced case label blocks: 0 (Max so far: 0)
The compiler grew to like 1.4 Gb in core. We spent most of the
time in CCP probably following the hundreds of thousands of
edges.
-----------------------------------------------------------------------------
tree gimplify : 0.13 ( 0%) usr 0.01 ( 0%) sys 0.15 ( 0%) wall
tree CFG construction : 0.72 ( 0%) usr 0.01 ( 0%) sys 0.72 ( 0%) wall
tree alias analysis : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.05 ( 0%) wall
tree PHI insertion : 10.28 ( 2%) usr 0.47 ( 1%) sys 10.82 ( 1%) wall
tree SSA rewrite : 17.83 ( 4%) usr 0.01 ( 0%) sys 17.90 ( 1%) wall
tree SSA other : 40.96 ( 8%) usr 16.23 (42%) sys 374.95 (27%) wall
tree CCP : 389.39 (77%) usr 3.82 (10%) sys 575.17 (41%) wall
tree DCE : 0.98 ( 0%) usr 0.90 ( 2%) sys 57.81 ( 4%) wall
dominance frontiers : 0.10 ( 0%) usr 0.00 ( 0%) sys 0.09 ( 0%) wall
-----------------------------------------------------------------------------
It would be interesting to see what the fully pruned form does
here. It also may be just that the graph is so fully connected
that we have little hope. I certainly haven't looked too deeply.
Brad, any insights into this code?
> My plan is to get the updated PHI insertion stuff flushed out today, then
> flush out my improvements to the aliasing code, then pop back to the
> bitmap vs varray discussion :-)
>
Cool :)
Diego.