[Bug inline-asm/42321] NEON/VFP registers from inline assembly clobber list are saved/restored incorrectly

[rearnsha at gcc dot gnu dot org]

------- Comment #3 from rearnsha at gcc dot gnu dot org  2009-12-07 15:55 -------
I can confirm both of these issues.

in asm statements GCC currently just treats 'q4' and 'd8' as aliases for s16
(which of course is just a 32-bit register); there's currently no way of
expressing that a larger entitiy is clobbered.  Of course, you won't see that
in the prologue/epilogue code because the whole D register is saved even if
just part of it has been used, but it could cause data-flow related issues
elsewhere.
in asm statements GCC currently just treats 'q4' and 'd8' as aliases for s16
(which of course is just a 32-bit register); there's currently no way of
expressing that a larger entitiy is clobbered.  Of course, you won't see that
in the prologue/epilogue code because the whole D register is saved even if
just part of it has been used, but it could cause data-flow related issues
elsewhere.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42321