ABI voilation

[Andrew Haley]

Ian Lance Taylor writes:
 > Andrew Haley <aph-gcc@littlepinkcloud.COM> writes:
 > 
 > > Geer Bosch asked "Can't we just explicitly align the stack frame to
 > > 128-bits during the function prologue, when we know that there are
 > > locals that require such alignment?"  This seems so obvious that I
 > > can't understand why it hasn't been done.
 > 
 > If you don't trust your startup code, use -mstackrealign or the
 > force_align_arg_pointer function attribute.
 > 
 > We don't do it by default because it is slower and most people don't
 > need it.

This doesn't make any sense to me.  From what people have been saying
here, using -Os *dealigns* the stack pointer, causing programs using
SSE etc to fail.  Do we seriously want this to happen?  Is -Os
supposed silently to break programs?

Andrew.