After https://github.com/llvm/llvm-project/pull/153643, there may be a
BranchOnCond with constant condition in the entry block.
Simplify those in removeBranchOnConst. This removes a number of
redundant conditional branch from entry blocks.
In some cases, it may also make the original scalar loop unreachable,
because we know it will never execute. In that case, we need to remove
the loop from LoopInfo, because all unreachable blocks may dominate each
other, making LoopInfo invalid. In those cases, we can also completely
remove the loop, for which I'll share a follow-up patch.
Depends on https://github.com/llvm/llvm-project/pull/153643.
PR: https://github.com/llvm/llvm-project/pull/154510
Dissolving the hierarchical VPlan CFG and converting abstract to
concrete recipes can expose additional simplification opportunities.
Do a final run of simplifyRecipes before executing the VPlan.
VPVectorPointer for part 0 is just the pointer operand. Simplify it
after unrolling. This removes a large number of redundant GEPs with
index 0.
PR: https://github.com/llvm/llvm-project/pull/149735
Materialize constant vector trip counts before ::execute, if the trip
count can be computed as Original (TC / (VF * UF)) * (VF * UF). For now
this excludes when the tail is folded or scalar epilogues are required.
This enables removing a number of redundant branches from the middle
block.
For now this is also only done when not vectorizing the epilogue, as the
simplification complicates stitching the 2 plans together.
PR: https://github.com/llvm/llvm-project/pull/142309
After unrolling, there may be additional simplifications that can be
applied. One example is removing SCALAR-STEPS for the first part where
only the first lane is demanded.
This removes redundant adds of 0 from a large number of tests (~200),
many which I am still working on updating.
In preparation for removing redundant WideIV steps added in
https://github.com/llvm/llvm-project/pull/119284.
PR: https://github.com/llvm/llvm-project/pull/123655
Use getAllocTypeSize to get compute the offset to the start of
interleave groups instead getScalarSizeInBits, which may return 0 for
pointers. This is in line with the analysis building the interleave
groups and fixes a mis-compile reported for
https://github.com/llvm/llvm-project/pull/106431.
Update VPInterleaveRecipe to always use the pointer to member 0 as
pointer argument. This in many cases helps to remove unneeded index
adjustments and simplifies VPInterleaveRecipe::execute.
In some rare cases, the address of member 0 does not dominate the insert
position of the interleave group. In those cases a PtrAdd VPInstruction
is emitted to compute the address of member 0 based on the address of
the insert position. Alternatively we could hoist the recipe computing
the address of member 0.
