This will result in a KMOVW or KMOVD being emitted during register allocation. And in at least some cases this might allow the register coalescer to remove the copy all together.
llvm-svn: 298984
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
We should probably teach the two address instruction pass to turn masked moves into BLENDM when its beneficial to the register allocator.
llvm-svn: 291371
Summary:
Scalar intrinsics have specific semantics about the which input's upper bits are passed through to the output. The same input is also supposed to be the input we use for the lower element when the mask bit is 0 in a masked operation. We aren't currently keeping these semantics with instruction selection.
This patch corrects this by introducing new scalar FMA ISD nodes that indicate whether operand 1(one of the multiply inputs) or operand 3(the additon/subtraction input) should pass thru its upper bits.
We use this information to select 213/132 form for the operand 1 version and the 231 form for the operand 3 version.
We also use this information to suppress combining FNEG operations on the passthru input since semantically the passthru bits aren't negated. This is stronger than the earlier check added for a user being SELECTS so we can remove that.
This fixes PR30913.
Reviewers: delena, zvi, v_klochkov
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27144
llvm-svn: 289190
The previous commit (r280368 - https://reviews.llvm.org/D23313) does not cover AVX-512F, KNL set.
FNEG(x) operation is lowered to (bitcast (vpxor (bitcast x), (bitcast constfp(0x80000000))).
It happens because FP XOR is not supported for 512-bit data types on KNL and we use integer XOR instead.
I added pattern match for integer XOR.
Differential Revision: https://reviews.llvm.org/D24221
llvm-svn: 280785
This helped to improved memory-folding and register coalescing optimizations.
Also, this patch fixed the tracker #17229.
Reviewer: Craig Topper.
Differential Revision: https://reviews.llvm.org/D23108
llvm-svn: 278431
Craig Topper