https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69501
Bug ID: 69501
Summary: PowerPC rs6000_adjust_cost doesn't recognize
float/sign/zero extend memory operations
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: meissner at gcc dot gnu.org
Target Milestone: ---
I was chasing down another bug, when I happened to look at rs6000_adjust_cost
in rs6000.c. In the REG_DEP_TRUE case of the switch statement, it tries to
separate a load from a narrower store. However, if the load is an extend:
(sign_extend:DI (mem:SI ...))
(zero_extend:DI (mem:SI ...))
(float_extend:DF (mem:SF ...))
It will not recognize this, and bump up the cost by 14. There might be other
places in the scheduling hooks where we miss opportunities with sign/zero
extension from memory.
