There are cases of AVX-512 instructions that have two possible encodings. This is the case with instructions that use vector registers with low indexes of 0 - 15 and do not use the zmm registers or the mask k registers.
The EVEX encoding prefix requires 4 bytes whereas the VEX prefix can take only up to 3 bytes. Consequently, using the VEX encoding for these instructions results in a code size reduction of ~2 bytes even though it is compiled with the AVX-512 features enabled.
Reviewers: Craig Topper, Zvi Rackoover, Elena Demikhovsky
Differential Revision: https://reviews.llvm.org/D27901
llvm-svn: 290663
These nodes are only emitted for lowering FABS/FNEG/FNABS/FCOPYSIGN. Ideally we just wouldn't create these nodes if SSE2 or higher is available, but it was simple to just convert them in DAG combine.
For SSE2, AVX, and AVX512 with DQI this is no functional change as the execution domain fixing pass ensures the right domain is selected regardless of the ISD opcode.
For AVX-512 without DQI we end up using integer instructions since the floating point versions aren't available. But we were already doing that for any logical operations in code that didn't come from FABS/FNEG/FNABS/FCOPYSIGN so this seems no worse. And we get the benefit of being able to fold broadcasts now.
llvm-svn: 290060
Summary:
This extends FCOPYSIGN support to 512-bit vectors.
I've also added tests to show what the 128-bit and 256-bit cases look like with broadcast loads.
Reviewers: delena, zvi, RKSimon, spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26791
llvm-svn: 287298
Gadi Haber