[PATCH 0/5] Fix handling of word subregs of wide registers
Fri Sep 19 06:14:00 GMT 2014
On 09/18/14 04:07, Richard Sandiford wrote:
> This series is a cleaned-up version of:
> The underlying problem is that the semantics of subregs depend on the
> word size. You can't have a subreg for byte 2 of a 4-byte word, say,
> but you can have a subreg for word 2 of a 4-word value (as well as lowpart
> subregs of that word, etc.). This causes problems when an architecture has
> wider-than-word registers, since the addressability of a word can then depend
> on which register class is used.
> The register allocators need to fix up cases where a subreg turns out to
> be invalid for a particular class. This is really an extension of what
> we need to do for CANNOT_CHANGE_MODE_CLASS.
> Tested on x86_64-linux-gnu, powerpc64-linux-gnu and aarch64_be-elf.
I thought we fixed these problems long ago with the change to subreg_byte?!?
Clearly I missed something.
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