This temporarily reverts commit 7019cea26d.
It seems that, for some targets, there are instructions with a lot of memory operands (probably more than would be expected). This causes a lot of buildbots to timeout and notify failed builds. While investigations are ongoing to find out why this happens, revert the changes.
Summary:
To support all targets, the mayAlias member function needs to support instructions with multiple operands.
This revision also changes the order of the emitted instructions in some test cases.
Reviewers: efriedma, hfinkel, craig.topper, dmgreen
Reviewed By: efriedma
Subscribers: MatzeB, dmgreen, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80161
In the ARM backend, for historical reasons we have only some targets
using Machine Scheduling. The rest use the old list scheduler as they
are using itinaries and the list scheduler seems to produce better code
(and not crash running out of register on v6m codes). So whether to use
the MIScheduler or not is checked at runtime from the subtarget
features.
This is fine, except for post-ra scheduling. Whether to use the old
post-ra list scheduler or the post-ra machine schedule is decided as the
pass manager is set up, in arms case from a newly constructed subtarget.
Under some situations, like LTO, this won't include the correct cpu so
can pick the wrong option. This can have a surprising effect on
performance.
To fix that, this patch overrides targetSchedulesPostRAScheduling and
addPreSched2 in the ARM backend, adding _both_ post-ra schedulers and
picking at runtime which to execute. To pick between the two I've had to
add a enablePostRAMachineScheduler() method that normally returns
enableMachineScheduler() && enablePostRAScheduler(), which can be
overridden to enable just one of PostRAMachineScheduler vs
PostRAScheduler.
Thanks to David Penry for the identifying this problem.
Differential Revision: https://reviews.llvm.org/D69775
Jean-Michel Gorius