We've had several bugs(PR32256, PR32241) recently that resulted from usages of AH/BH/CH/DH either before or after a copy to/from a mask register.
This ultimately occurs because we create COPY_TO_REGCLASS with VK1 and GR8. Then in CopyToFromAsymmetricReg in X86InstrInfo we find a 32-bit super register for the GR8 to emit the KMOV with. But as these tests are demonstrating, its possible for the GR8 register to be a high register and we end up doing an accidental extra or insert from bits 15:8.
I think the best way forward is to stop making copies directly between mask registers and GR8/GR16. Instead I think we should restrict to only copies between mask registers and GR32/GR64 and use EXTRACT_SUBREG/INSERT_SUBREG to handle the conversion from GR32 to GR16/8 or vice versa.
Unfortunately, this complicates fastisel a bit more now to create the subreg extracts where we used to create GR8 copies. We can probably make a helper function to bring down the repitition.
This does result in KMOVD being used for copies when BWI is available because we don't know the original mask register size. This caused a lot of deltas on tests because we have to split the checks for KMOVD vs KMOVW based on BWI.
Differential Revision: https://reviews.llvm.org/D30968
llvm-svn: 298928
Some shuffles can be lowered to blend mask instruction (VPBLENDMB/VPBLENDMW/VPBLENDMD/VPBLENDMQ) .
In this patch, I added new pattern match for this case.
Reviewers:
1. craig.topper
2. guyblank
3. RKSimon
4. igorb
Differential Revision: https://reviews.llvm.org/D28483
llvm-svn: 291888
Add the missing domain equivalences for movss, movsd, movd and movq zero extending loading instructions.
Differential Revision: https://reviews.llvm.org/D27684
llvm-svn: 289825
Summary:
The index and one of the table operands can be swapped by changing the opcode to the other version. Neither of these operands are the one that can load from memory so this can't be used to increase memory folding opportunities.
We need to handle the unmasked forms and the kz forms. Since the load operand isn't being commuted we can commute the load and broadcast instructions too.
Reviewers: igorb, delena, Ayal, Farhana, RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25652
llvm-svn: 287621
Add support for the case where we have a consecutive load (which must include the first + last elements) with a mixture of undef/zero elements. We load the vector and then apply a shuffle to clear the zero'd elements.
Differential Revision: http://reviews.llvm.org/D17297
llvm-svn: 261490
Choose between MOVD/MOVSS and MOVQ/MOVSD depending on the target vector type.
This has a lot fewer test changes than trying to add this to X86InstrInfo::setExecutionDomain.....
llvm-svn: 259816
This patch adds support for consecutive (load/undef elements) 32-bit loads, followed by trailing undef/zero elements to be combined to a single MOVD load.
Differential Revision: http://reviews.llvm.org/D16729
llvm-svn: 259796
Follow up to D16217 and D16729
This change uncovered an odd pattern where VZEXT_LOAD v4i64 was being lowered to a load of the lower v2i64 (so the 2nd i64 destination element wasn't being zeroed), I can't find any use/reason for this and have removed the pattern and replaced it so only the 1st i64 element is loaded and the upper bits all zeroed. This matches the description for X86ISD::VZEXT_LOAD
Differential Revision: http://reviews.llvm.org/D16768
llvm-svn: 259635
Craig Topper