Reassociate adds to collect scalar operands in a single
instruction when possible. That will result in a scalar
add followed by vector instead of two vector adds, thus
better utilizing SALU.
Differential Revision: https://reviews.llvm.org/D58220
llvm-svn: 354066
Summary:
We have seen performance regression when v_add3 is generated. The major reason is that the v_mad pattern
is broken when v_add3 is generated. We also see the register pressure increased. While we could not properly
estimate register pressure during instruction selection, we can give mad a higher priority.
In this work, we raise the priority for mad24 in selection and resolve the performance regression.
Reviewers:
rampitec
Differential Revision:
https://reviews.llvm.org/D56745
llvm-svn: 351273
Stanislav Mekhanoshin