Similar to 806761a7629df268c8aed49657aeccffa6bca449.
For IR files without a target triple, -mtriple= specifies the full
target triple while -march= merely sets the architecture part of the
default target triple, leaving a target triple which may not make sense,
e.g. amdgpu-apple-darwin.
Therefore, -march= is error-prone and not recommended for tests without
a target triple. The issue has been benign as we recognize
$unknown-apple-darwin as ELF instead of rejecting it outrightly.
This patch changes AMDGPU tests to not rely on the default
OS/environment components. Tests that need fixes are not changed:
```
LLVM :: CodeGen/AMDGPU/fabs.f64.ll
LLVM :: CodeGen/AMDGPU/fabs.ll
LLVM :: CodeGen/AMDGPU/floor.ll
LLVM :: CodeGen/AMDGPU/fneg-fabs.f64.ll
LLVM :: CodeGen/AMDGPU/fneg-fabs.ll
LLVM :: CodeGen/AMDGPU/r600-infinite-loop-bug-while-reorganizing-vector.ll
LLVM :: CodeGen/AMDGPU/schedule-if-2.ll
```
si-wqm sometimes needs to save the LiveMask in the entry block. Later
on, while looking for a place to enter WQM/WWM, it unconditionally
skips over the first COPY instruction in the entry block. This is
incorrect for functions where the LiveMask doesn't need to be saved, and
therefore the first COPY is more likely a COPY from a function argument
and might need to be in some non-exact mode.
This patch fixes the issue by also checking that the source of the COPY
is the EXEC register.
This produces different code in 3 of the existing tests:
In wwm-reserved.ll, a SGPR copy is now inside the WWM area rather than
outside. This is benign.
In wave32.ll, we end up with an extra register copy. This is because
the first COPY in the block is now part of the WWM block, so
si-pre-allocate-wwm-regs will allocate a new register for its
destination (when it was outside of the WWM region, the register
allocator could just re-use the same register). We might be able to
improve this in si-pre-allocate-wwm-regs but I haven't looked into it.
The same thing happens in dual-source-blend-export.ll, but for that
one it's harder to see because of the scheduling changes. I've uploaded
the before/after si-wqm output for it here:
https://reviews.llvm.org/differential/diff/553445/
Differential Revision: https://reviews.llvm.org/D158841
PR #66334 tried to renumber slot indexes before register allocation, but
the numbering was still affected by list entries for instructions which
had been erased. Fix this to make the register allocator's live range
length heuristics even less dependent on the history of how instructions
have been added to and removed from SlotIndexes's maps.
RegAllocGreedy uses SlotIndexes::getApproxInstrDistance to approximate
the length of a live range for its heuristics. Renumbering all slot
indexes with the default instruction distance ensures that this estimate
will be as accurate as possible, and will not depend on the history of
how instructions have been added to and removed from SlotIndexes's maps.
This also means that enabling -early-live-intervals, which runs the
SlotIndexes analysis earlier, will not cause large amounts of churn due
to different register allocator decisions.
This happens when CMP1 and CMP3 have the same predicate (or CMP2 and CMP3 have
the same predicate).
This helps optimizations such as the fololowing one:
CMP(A,C)||CMP(B,C) => CMP(MIN/MAX(A,B), C)
CMP(A,C)&&CMP(B,C) => CMP(MIN/MAX(A,B), C)
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D156215
This reverts commit a496c8be6e638ae58bb45f13113dbe3a4b7b23fd.
The workaround in c26dfc81e254c78dc23579cf3d1336f77249e1f6 should work
around the underlying problem with SUBREG_TO_REG.
And dependent commits.
Details in D150388.
This reverts commit 825b7f0ca5f2211ec3c93139f98d1e24048c225c.
This reverts commit 7a98f084c4d121244ef7286bc6503b6a181d446e.
This reverts commit b4a62b1fa546312d882fa12dfdcd015177d66826.
This reverts commit b7836d856206ec39509d42529f958c920368166b.
No conflicts in the code, few tests had conflicts in autogenerated CHECKs:
llvm/test/CodeGen/Thumb2/mve-float32regloops.ll
llvm/test/CodeGen/AMDGPU/fix-frame-reg-in-custom-csr-spills.ll
Reviewed By: alexfh
Differential Revision: https://reviews.llvm.org/D156381
Inspired by some of the cases from D145468
Let SimplifyDemandedBits handle the narrowing of lshr to half-width if we don't require the upper bits, the narrowed shift is profitable and the zext/trunc are free.
A future patch will propose the equivalent shl narrowing combine.
Differential Revision: https://reviews.llvm.org/D146121
Currently, the custom SGPR spill lowering pass spills
SGPRs into physical VGPR lanes and the remaining VGPRs
are used by regalloc for vector regclass allocation.
This imposes many restrictions that we ended up with
unsuccessful SGPR spilling when there won't be enough
VGPRs and we are forced to spill the leftover into
memory during PEI. The custom spill handling during PEI
has many edge cases and often breaks the compiler time
to time.
This patch implements spilling SGPRs into virtual VGPR
lanes. Since we now split the register allocation for
SGPRs and VGPRs, the virtual registers introduced for
the spill lanes would get allocated automatically in
the subsequent regalloc invocation for VGPRs.
Spill to virtual registers will always be successful,
even in the high-pressure situations, and hence it avoids
most of the edge cases during PEI. We are now left with
only the custom SGPR spills during PEI for special registers
like the frame pointer which is an unproblematic case.
Differential Revision: https://reviews.llvm.org/D124196
SIInsertWaitcnts inserts waitcnt instructions to resolve data
dependencies. The GFX10+ vscnt (VMEM store count) counter is never used
in this way. It is only used to resolve memory dependencies, and that is
handled by SIMemoryLegalizer. Hence there is no need to conservatively
wait for vscnt to be 0 on function entry and before returns.
Differential Revision: https://reviews.llvm.org/D153537
In order to enable the LLVM frontend to better analyze buffer
operations (and to potentially enable more precise analyses on the
backend), define versions of the raw and structured buffer intrinsics
that use `ptr addrspace(8)` instead of `<4 x i32>` to represent their
rsrc arguments.
The new intrinsics are named by replacing `buffer.` with `buffer.ptr`.
One advantage to these intrinsic definitions is that, instead of
specifying that a buffer load/store will read/write some memory, we
can indicate that the memory read or written will be based on the
pointer argument. This means that, for example, a read from a
`noalias` buffer can be pulled out of a loop that is modifying a
distinct buffer.
In the future, we will define custom PseudoSourceValues that will
allow us to package up the (buffer, index, offset) triples that buffer
intrinsics contain and allow for more precise backend analysis.
This work also enables creating address space 7, which represents
manipulation of raw buffers using native LLVM load and store
instructions.
Where tests simply used a buffer intrinsic while testing some other
code path (such as the tests for VGPR spills), they have been updated
to use the new intrinsic form. Tests that are "about" buffer
intrinsics (for instance, those that ensure that they codegen as
expected) have been duplicated, either within existing files or into
new ones.
Depends on D145441
Reviewed By: arsenm, #amdgpu
Differential Revision: https://reviews.llvm.org/D147547
In some cases, breaking large PHIs can very negatively affect
performance (3x more instructions observed in a particular test case).
This patch adds some basic profitability heuristics to help with some of these issues without affecting the "good" cases.
e.g. avoid breaking PHIs if it causes back-and-forth between vector/scalar form for no good reason.
Fixes SWDEV-392803
Fixes SWDEV-393781
Fixes SWDEV-394228
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D147786
DAGISel uses CopyToReg/CopyFromReg to lower PHI nodes. With large PHIs, this can result in poor codegen.
This is because it introduces a need to have a build_vector before copying the PHI value, and that build_vector may have many undef elements. This can cause very high register pressure and abnormal stack usage in some cases.
This scalarization/phi "break-up" can be easily tuned/disabled through CL options in case it's not beneficial for some users.
It's also only enabled for DAGIsel and GlobalISel handles PHIs much better (as it works on the whole function).
This can both scalarize (break a vector into its elements) and simplify (break a vector into smaller, more manageable subvectors) PHIs.
Fixes SWDEV-321581
Reviewed By: kzhuravl
Differential Revision: https://reviews.llvm.org/D143731
We don't do this transform in InstCombine in general case for arbitrary values, because cost of
AND and 2 ICMP's isn't higher than of MIN and ICMP. However, LICM also has a notion
about the loop structure. This transform becomes profitable if `A` and `B` are loop-invariant and
`X` is not: by doing this, we can compute min outside the loop.
Differential Revision: https://reviews.llvm.org/D143726
Reviewed By: nikic
Unlike the callee-saved VGPR spill instructions emitted by
`PEI::spillCalleeSavedRegs`, the CS VGPR spills inserted during
emitPrologue/emitEpilogue require the exec bits flipping to avoid
clobbering the inactive lanes of VGPRs used for SGPR spilling.
Currently, these spill instructions are referenced from the SP at
function entry and when the callee performs a stack realignment,
they ended up getting incorrect stack offsets. Even if we try to
adjust the offsets, the FP-SP becomes a runtime entity with dynamic
stack realignment and the offsets would still be inaccurate.
To fix it, use FP as the frame base in the spill instructions
whenever the function has FP. The offsets obtained for the CS
objects would always be the right values from FP.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D134949
SILowerSGPRSpills pass handles the lowering of SGPR spills
into VGPR lanes. Some SGPR spills are handled later during
PEI. There is a common function used in both places to find
the free VGPR lane. This patch eliminates that dependency to
find the free VGPR by handling it separately for PEI. It is a
prerequisite patch for a future work to allow SGPR spills to
virtual VGPR lanes during SILowerSGPRSpills.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D124195
Since the divergence-driven instruction selection has been enabled for AMDGPU,
all the uniform instructions are expected to be selected to SALU form, except those not having one.
VGPR to SGPR copies appear in MIR to connect values producers and consumers. This change implements an algorithm
that evolves a reasonable tradeoff between the profit achieved from keeping the uniform instructions in SALU form
and overhead introduced by the data transfer between the VGPRs and SGPRs.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D128252
Pre gfx1030 null for sdst is different.
c97436f8b6e2 [AMDGPU] Use null for dead sdst operand - requires a change to make
it not apply to pre gfx1030
Differential Revision: https://reviews.llvm.org/D127869
Currently the return address ABI registers s[30:31], which fall in the call
clobbered register range, are added as a live-in on the function entry to
preserve its value when we have calls so that it gets saved and restored
around the calls.
But the DWARF unwind information (CFI) needs to track where the return address
resides in a frame and the above approach makes it difficult to track the
return address when the CFI information is emitted during the frame lowering,
due to the involvment of understanding the control flow.
This patch moves the return address ABI registers s[30:31] into callee saved
registers range and stops adding live-in for return address registers, so that
the CFI machinery will know where the return address resides when CSR
save/restore happen during the frame lowering.
And doing the above poses an issue that now the return instruction uses undefined
register `sgpr30_sgpr31`. This is resolved by hiding the return address register
use by the return instruction through the `SI_RETURN` pseudo instruction, which
doesn't take any input operands, until the `SI_RETURN` pseudo gets lowered to the
`S_SETPC_B64_return` during the `expandPostRAPseudo()`.
As an added benefit, this patch simplifies overall return instruction handling.
Note: The AMDGPU CFI changes are there only in the downstream code and another
version of this patch will be posted for review for the downstream code.
Reviewed By: arsenm, ronlieb
Differential Revision: https://reviews.llvm.org/D114652
Extend pre-emit peephole for S_CBRANCH_VCC[N]Z to eliminate
redundant S_AND operations against EXEC for V_CMP results in VCC.
These occur after after register allocation when VCC has been
selected as the comparison destination.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D120202
This reverts commit a6b54ddaba2d5dc0f72dcc4591c92b9544eb0016.
Apparently it is not safe to modify the condition even if it passes the
hasOneUse test, because StructurizeCFG might have other references to
the condition that are not manifest in the IR use-def chains.
This avoids various cases where StructurizeCFG would otherwise insert an
xor i1 instruction, and it since it generally runs late in the pipeline,
instcombine does not clean up the xor-of-cmp pattern.
Differential Revision: https://reviews.llvm.org/D118478
Currently the return address ABI registers s[30:31], which fall in the call
clobbered register range, are added as a live-in on the function entry to
preserve its value when we have calls so that it gets saved and restored
around the calls.
But the DWARF unwind information (CFI) needs to track where the return address
resides in a frame and the above approach makes it difficult to track the
return address when the CFI information is emitted during the frame lowering,
due to the involvment of understanding the control flow.
This patch moves the return address ABI registers s[30:31] into callee saved
registers range and stops adding live-in for return address registers, so that
the CFI machinery will know where the return address resides when CSR
save/restore happen during the frame lowering.
And doing the above poses an issue that now the return instruction uses undefined
register `sgpr30_sgpr31`. This is resolved by hiding the return address register
use by the return instruction through the `SI_RETURN` pseudo instruction, which
doesn't take any input operands, until the `SI_RETURN` pseudo gets lowered to the
`S_SETPC_B64_return` during the `expandPostRAPseudo()`.
As an added benefit, this patch simplifies overall return instruction handling.
Note: The AMDGPU CFI changes are there only in the downstream code and another
version of this patch will be posted for review for the downstream code.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D114652
The compiler was generating symbols in the final code object for local
branch target labels. This bloats the code object, slows down the loader,
and is only used to simplify disassembly.
Use '--symbolize-operands' with llvm-objdump to improve readability of the
branch target operands in disassembly.
Fixes: SWDEV-312223
Reviewed By: scott.linder
Differential Revision: https://reviews.llvm.org/D114273
The old expansion open-coded a 64-bit addition in a strange way, by
adding the high parts *without* carry-in from the low part, and then
adding the carry back in later on. Fixing this saves a couple of
instructions and makes the code much easier to understand.
Differential Revision: https://reviews.llvm.org/D113679
MachineLoop::isLoopInvariant() returns false for all VALU
because of the exec use. Check TII::isIgnorableUse() to
allow hoisting.
That unfortunately results in higher register consumption
since MachineLICM does not adequately estimate pressure.
Therefor I think it shall only be enabled after D107677 even
though it does not depend on it.
Differential Revision: https://reviews.llvm.org/D107859
Currently, the truncate selection dag node is expanded as a bitwise AND plus compare to 1. This change enables scalar comparison in the pattern if the truncate node is uniform.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D108925
Description: This change enables the compare operations to be selected to SALU/VALU form
dependent of the SDNode divergence flag.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D106079
This allows to convert the add instruction to s_addk_i32 and
v_add_nc_u32 instead of needing v_add_co_u32 when converting to a VALU
instruction.
Differential Revision: https://reviews.llvm.org/D103322
