[Bug rtl-optimization/45678] [4.4/4.5/4.6 Regression] crash on vector code with -m32 -msse

[jakub at gcc dot gnu dot org]

------- Comment #14 from jakub at gcc dot gnu dot org  2010-09-16 13:54 -------
The reason why cfgexpand does increase the alignment is that it believes that
the base slot will be at least PREFERRED_STACK_BOUNDARY bytes aligned, which is
true on all targets but i?86/x86-64, which apparently sometimes chooses even
smaller alignment for the stack base.  So, we can either use there
MAX (..., STACK_BOUNDARY); for STACK_ALIGNMENT_SUPPORTED instead, which might
penalize some code though, or use INCOMING_STACK_BOUNDARY there (after making
sure we compute it before) and bump needed alignment to whatever we pick there
up.  During expansion expanders of course make use of the DECL_ALIGN info
cfgexpand provides, after all that's why we do that. 


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45678