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Re: [tree-ssa] dead const/pure/alloca call removal
Jan Hubicka <hubicka@ucw.cz> writes:
> Are you really sure we want to clear alloca too? It has side effect.
> Only I know that given the semantic of alloca the side effect is useless
> when return value is thrown away.
I don't know what the right thing is, but I'd point out that this
optimization applies to all functions whose side effect is to allocate
a new block of memory, the sole pointer to which is returned. malloc
and calloc (but not realloc) are the obvious examples.
However, I am a little worried about deleting calls to memory
allocation functions whose return value is discarded. People may be
doing clever things, like using a dummy call to alloca to force extra
stack alignment.
zw