This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [ tree-ssa] PRE problem

On Feb 20, 2004, at 12:50 PM, Daniel Berlin wrote:

Seems reasonable.

The problem is we do this substitution (reverse copy propagation) *without*
fixing up the annotation for method_signature.3. Specifically, if we do this
kind of substitution we need to fix is_dereferenced_{load,store} and
type_mem_tag in method_signature.3's annotation.

This is not copy propagation code.
It's verifying the safety of a rename.
We don't actually use the generated expressions except to check their versions in the part you are quoting.

We do, however, insert these expressions later if their safety has been verified (IE there are two uses of generate_expr_as_of_bb, but the changes you've made make no sense for the first, and main, use)
So i'm not sure what problem this causes for you.
Are we actually generating and *inserting* an illegal expression?

And if we are generating and inserting an illegal expression , please provide me a preprocessed testcase and i'll be happy to make sure the rename algorithm doesn't mark it as safe.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]