http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54565
Bug #: 54565
Summary: pass_update_address_taken before forwprop1 for vectors
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: gli...@gcc.gnu.org
Created attachment 28186
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28186
IRC log
Hello,
during forwprop1, some of the optimizations for vectors fail because some
vectors appear as PARM_DECL or such instead of SSA_NAME. An example is
forwprop-22.c where the code does detect that {v[0],v[1]} is just v, but v is a
PARM_DECL so it just gives up. Before forwprop2, something (fre?) changes it to
an SSA_NAME and the optimization then works. Following some advice by pinskia
and stevenb on IRC (log attached), I tried adding pass_update_address_taken
right before forwprop1 and it did allow the optimization to happen in
forwprop1. The log also contains an argument by pinskia that doing
optimizations in forwprop1 can help a bit make better inlining decisions, and
some later comments by richi.
