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[Bug tree-optimization/77399] Poor code generation for vector casts and loads
- From: "rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 30 Aug 2016 09:36:18 +0000
- Subject: [Bug tree-optimization/77399] Poor code generation for vector casts and loads
- Auto-submitted: auto-generated
- References: <bug-77399-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77399
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note that this is a patten matching issue that could be quite easily fixed in
tree-ssa-forwprop.c:simplify_vector_constructor (which currently recognizes
a VEC_PERM but it should be easy to handle intermediate conversions meaning
to handle even pack-/unpack-style permuted (float-int) conversions).
Just to give a hint where this can be handled. [yeah, match.pd but there
we'd need a way to handle variable-length stuff like CONSTRUCTORs first...,
see the "awkward" handling of BIT_FIELD_REF <CONSTRUCTOR, ..> there]