http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56612
Bug #: 56612
Summary: basic-block vectorization does not replace all scalar
uses
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: [email protected]
ReportedBy: [email protected]
When vectorizing stmts in a basic-block we do not verify that the SLP
instance covers all uses of the definitions the stmts in the SLP tree.
This can easily result in both the scalar and vectorized set of stmts
being kept live and executed.
See PR56608 for an example (trivial re-use of the SLP roots stored values).
