A handy shorthand for specifying the shufflevector(insertelement(poison,
foo, 0), poison, zeroinitializer) splat pattern was introduced in
#74620.
Some of the RISC-V tests were converted over to use this new form in
dbb65dd330cc1696d7ca3dedc7aa9fa12c55a075, this patch handles the rest
which didn't have any codegen diffs.
This not only converts some constant expressions to the new form, but
also instruction sequences that weren't previously constant expressions
to constant expressions as well. In some cases this affects codegen, but
these have been omitted here and will be handled in a separate PR.
If we know that an insert_subvector inserting a fixed subvector will
overwrite the entire tail of the vector, we use a tail agnostic
vslideup. This was added in https://reviews.llvm.org/D147347, but we can
do the same thing for scalable vectors too.
The `Policy` variable is defined in a slightly weird place but this is
to mirror the fixed length subvector code path as closely as possible. I
think we may be able to deduplicate them in future.
This changes the default value used for mask policy from mask undisturbed to mask agnostic. In hardware, there may be a minor preference for ta/ma, but since this is only going to apply to instructions which don't use the mask policy bit, this is functionally mostly a nop. The main value is to make future changes to using MA when legal for masked instructions easier to review by reducing test churn.
The prior code was motivated by a desire to minimize state transitions between masked and unmasked code. This patch achieves the same effect using the demanded field logic (landed in afb45ff), and there are no regressions I spotted in the test diffs. (Given the size, I have only been able to skim.) I do want to call out that regressions are possible here; the demanded analysis only works on a block local scope right now, so e.g. a tight loop mixing masked and unmasked computation might see an extra vsetvli or two.
Differential Revision: https://reviews.llvm.org/D133803
RVV doesn't have immediate field for memory addressing. Currently
we build MachineInstructions in PEI to computing stack offset for
RVV load store instructions. These instructions were added too late to
can be optimized by CSE, LICM... passes.
This patch makes FrameIndex SDNodes can't be matched in RVV Load Store
instruction selection patterns. So that the FrameIndex SDNodes would be
selected as `ADDI GPR, targetframeindex`.
There are 2 advantages for such change:
1. Stack objects address computing can be optimized by machine function
passes.
2. Since the ADDI instruction's destination register can be used as a
temp register, we can save an emergency spill slot.
Differential Revision: https://reviews.llvm.org/D128187
We need to use tail undisturbed for vslideup to implement
vector insert operation correctly.
Ideally, we cound use the tail agnostic when insert subvector
or element at the end of the vector. This will be in follow-up
patch.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D125545
vslideup works by leaving elements 0<i<OFFSET undisturbed.
so it need the destination operand as input for correctness
regardless of policy. Add a operand to indicate policy.
We also add policy operand for unmaksed vslidedown to keep the interface consistent with vslideup
because vslidedown have only undisturbed at 0<i<vstart but user have no way to control of vstart.
Reviewed By: rogfer01, craig.topper
Differential Revision: https://reviews.llvm.org/D124186
This patch synchronizes the structure of the templates with those
in RISCVInstrInfoVVLPatterns.td so that we get patterns with .vx
on the left hand side.
Reviewed By: rogfer01
Differential Revision: https://reviews.llvm.org/D123255
