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Re: [patch] Improve basic block merging


Zdenek Dvorak wrote on 11/11/06 17:27:

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).

Well, not "ignored". They are used if present, and inserted if needed. But your observation is valid.

	* 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.

s/non_symbol_need_ssa_update_p/name_mappings_registered_p/

+ /* Return true if any non-symbol is registered for ssa updating. */
+
/* Return true if SSA name mappings have been registered for SSA updating. */


OK with those changes.



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