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Re: [patch] Improve basic block merging
- From: Diego Novillo <dnovillo at redhat dot com>
- To: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Sun, 12 Nov 2006 11:48:14 -0500
- Subject: Re: [patch] Improve basic block merging
- References: <20061111222730.GA31758@atrey.karlin.mff.cuni.cz>
Zdenek Dvorak wrote on 11/11/06 17:27:
Well, not "ignored". They are used if present, and inserted if needed.
But your observation is valid.
This behavior is overly conservative. If only symbols are marked for
renaming (not ssa names), then eliminating the phi nodes is still
safe (as the phi nodes for the affected symbols are ignored during
ssa update, anyway).
* tree-flow.h (non_symbol_need_ssa_update_p): Declare.
* tree-into-ssa.c (non_symbol_need_ssa_update_p): New function.
* tree-cfg.c (tree_can_merge_blocks_p): Check
non_symbol_need_ssa_update_p instead of need_ssa_update_p.
+ /* Return true if any non-symbol is registered for ssa updating. *//* Return true if SSA name mappings have been registered for SSA
OK with those changes.