The avoid-store-forwarding pass is disabled by default and therefore
in the risk of bit-rotting. This patch addresses this by enabling
the pass at O2 or higher.
We are, also, adding the target-specific cost function
`avoid_store_forwarding_reorder_cost_p`. There is no specific implementation
for this at the time. It always returns "true" on AArch64 and the return value
depends on the newly added `asf-default-cost-value` parameter for all the other
targets, which is "false" by default.
Bootstrapped/regtested on AArch64 and x86_64.
Changes in v3:
- Add `avoid_store_forwarding_reorder_cost_p` function
- Add `asf-default-cost-value` parameter
- Use `avoid_store_forwarding_reorder_cost_p` for each store in ASF.
- Update x86_64 testcases.
- Update assembly patterns in `bitfield-bitint-abi-align16.c` and
`bitfield-bitint-abi-align8.c`.
- Fix bug where the result of `store_bit_field` is not used in the
following instructions.
Changes in v2:
- Update assembly patterns in `bitfield-bitint-abi-align16.c` and
`bitfield-bitint-abi-align8.c`.
Changes in v1:
- Enable asf by default at O2 or higher.
Konstantinos Eleftheriou (4):
asf: Add cost function for store/load reordering
aarch64: Add implementation for avoid_store_forwarding_reorder_cost_p
asf: Check store-load reordering cost before applying the
transformation
asf: Update destination register after store_bit_field when needed
kelefth (1):
asf: Enable pass at O2 or higher
gcc/avoid-store-forwarding.cc | 55 ++++++++++++++++++-
gcc/config/aarch64/aarch64.cc | 13 +++++
gcc/doc/invoke.texi | 3 +-
gcc/doc/tm.texi | 7 +++
gcc/doc/tm.texi.in | 2 +
gcc/opts.cc | 1 +
gcc/params.opt | 4 ++
gcc/target.def | 9 +++
gcc/targhooks.cc | 9 +++
gcc/targhooks.h | 5 ++
.../aarch64/avoid-store-forwarding-6.c | 29 ++++++++++
.../aarch64/bitfield-bitint-abi-align16.c | 25 +++++----
.../aarch64/bitfield-bitint-abi-align8.c | 25 +++++----
.../abi/callabi/avoid-store-forwarding-1.c | 2 +-
.../abi/callabi/avoid-store-forwarding-2.c | 2 +-
15 files changed, 164 insertions(+), 27 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/aarch64/avoid-store-forwarding-6.c
--
2.50.1
