This patch reworks the fix from D20627 "Do not rename registers that do
not start an independent live range". That fix depended on the scheduler
dependency graph having redundant edges. Those edges are removed by
D156552 "[MachineScheduler] Track physical register dependencies
per-regunit" with the result that on several Hexagon lit tests, the
post-RA scheduler would schedule the code in a way that fails machine
verification.
Consider this code where D11 is a pair R23:R22:
SU(0): %R2<def> = A2_add %R23, %R17<kill>
(anti dependency on R23 here)
SU(8): %R23<def> = S2_asr_i_r %R22, 31
(data dependency on R23->D11 here)
SU(10): %D0<def> = A2_tfrp %D11<kill>
The original fix would detect this situation by examining the dependency
from SU(8) to SU(10) and seeing that D11 is not a subreg of R23.
A slightly more complicated example:
SU(0): %R2<def> = A2_add %R23, %R17<kill>
(anti dependency on R23 here)
SU(8): %R23<def> = S2_asr_i_r %R22, 31
(data dependency on R23 here)
SU(9): %R23<def> = S2_asr_i_r %R23, 31
(data dependency on R23->D11 here)
SU(10): %D0<def> = A2_tfrp %D11<kill>
The original fix also worked on this example, but only because
ScheduleDAGInstrs adds an extra data dependency edge directly from SU(8)
to SU(10). This edge is redundant, since you could infer it transitively
from the edges SU(8)->SU(9) and SU(9)->SU(10), and since none of the
data that SU(8) writes to R23 is read by SU(10).
After D156552 the redundant edge SU(8)->SU(10) will not be present, so
when we examine the successors of SU(8) we will not find any that read
from a superreg of R23.
This patch removes the original fix from D20627, which examined edges in
the dependency graph. Instead it extends a check that was already being
done in FindSuitableFreeRegisters: instead of checking that *some*
register is a superreg of all registers in the rename group, we now
check that the specific register that carries the anti-dependency that
we want to break is a superreg of all registers in the rename group.
Differential Revision: https://reviews.llvm.org/D156880
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).
llvm-svn: 318490
Take parameters as MachineInstr& instead of MachineInstr* in
AntiDepBreaker API, since these are required to be non-null. No
functionality change intended. Looking toward PR26753.
llvm-svn: 262145
The patch is generated using this command:
tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
llvm/lib/
Thanks to Eugene Kosov for the original patch!
llvm-svn: 240137
The patch is generated using clang-tidy misc-use-override check.
This command was used:
tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py \
-checks='-*,misc-use-override' -header-filter='llvm|clang' \
-j=32 -fix -format
http://reviews.llvm.org/D8925
llvm-svn: 234679
Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)
Changes made by clang-tidy with minor tweaks.
llvm-svn: 215558
missed in the first pass because the script didn't yet handle include
guards.
Note that the script is now able to handle all of these headers without
manual edits. =]
llvm-svn: 169224
