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Re: Incomplete TREE_CONSTANT-propagation in build() ?
Ziemowit Laski <zlaski@apple.com> writes:
| On 4 Nov, 2003, at 12.23, Gabriel Dos Reis wrote:
|
| > Ziemowit Laski <zlaski@apple.com> writes:
| >
| > | P.S. For the morbidly curious, I'm working on Motorola-style AltiVec
| > | support in the 3.4 tree, and I really need compound expressions like
| > | '(1, 2, 3, 4)' to be marked TREE_CONSTANT. :-)
| >
| > Why don't you use VECTOR_CST?
|
| I am, but before they become VECTOR_CSTs, they are COMPOUND_EXPRs (due
| to the parenthesized Motorola notation).
OK, understood. However, I would think that a TREE_LIST would be much
more appropriate: it really is a list of constant expression instead
of a sequence of expressions, evaluated and discarded except the last
one. It would be really helpful if the front-ends could be made much
more consistent in that area.
| > A compound expression is NEVER a constant expression EVEN if its
| > operands are all constant expressions.
|
| Why not?
I have no idea of the raionale behond "that is what the standard says".
-- Gaby