[tree-ssa] Removing useless/redundant "const" calls

[Michael Matz]

Hi,

On Wed, 11 Jun 2003 law@redhat.com wrote:

> This is the final patch needed to allow the compiler to remove
> useless or redundant calls to "const" functions.  It fixes
> gcc.dg/tree-ssa/20030611-1.c.

There is no reason to not also remove useless calls to "pure" functions.
They too have by definition no side-effects.  Sure, they can read global
memory (and hence proving "redundant" is harder), but this isn't a
side-effect in the sense that it prevents removal.  So, shouldn't
TREE_SIDE_EFFECTS also be cleared for pure functions?


Ciao,
Michael.