Rename the function to reflect its correct behavior and to be consistent
with `Module::getOrInsertFunction`. This is also in preparation of
adding a new `Intrinsic::getDeclaration` that will have behavior similar
to `Module::getFunction` (i.e, just lookup, no creation).
Both input and output of ballot are lane-masks:
result is lane-mask with 'S32/S64 LLT and SGPR bank'
input is lane-mask with 'S1 LLT and VCC reg bank'.
Ballot copies bits from input lane-mask for
all active lanes and puts 0 for inactive lanes.
GlobalISel did not set 0 in result for inactive lanes
for non-constant input.
The current `selectVOP3PMadMixModsImpl` can produce `V_MAD_FIX_F32`
instruction
that violates constant bus restriction, while its `SelectionDAG`
counterpart
doesn't. The culprit is in the copy stripping while the `SelectionDAG`
version
only has a bitcast stripping. This PR simply aligns the two version.
This reverts commit
7792b4ae79.
The problem was a conflict with
e55d6f5ea2
"[AMDGPU] Simplify and improve codegen for llvm.amdgcn.set.inactive
(https://github.com/llvm/llvm-project/pull/107889)"
which changed the syntax of V_SET_INACTIVE (and thus made my MIR test
crash).
...if only we had a merge queue.
Reverts llvm/llvm-project#108173
si-init-whole-wave.mir crashes on some buildbots (although it passed
both locally with sanitizers enabled and in pre-merge tests).
Investigating.
This intrinsic is meant to be used in functions that have a "tail" that
needs to be run with all the lanes enabled. The "tail" may contain
complex control flow that makes it unsuitable for the use of the
existing WWM intrinsics. Instead, we will pretend that the function
starts with all the lanes enabled, then branches into the actual body of
the function for the lanes that were meant to run it, and then finally
all the lanes will rejoin and run the tail.
As such, the intrinsic will return the EXEC mask for the body of the
function, and is meant to be used only as part of a very limited pattern
(for now only in amdgpu_cs_chain functions):
```
entry:
%func_exec = call i1 @llvm.amdgcn.init.whole.wave()
br i1 %func_exec, label %func, label %tail
func:
; ... stuff that should run with the actual EXEC mask
br label %tail
tail:
; ... stuff that runs with all the lanes enabled;
; can contain more than one basic block
```
It's an error to use the result of this intrinsic for anything
other than a branch (but unfortunately checking that in the verifier is
non-trivial because SIAnnotateControlFlow will introduce an amdgcn.if
between the intrinsic and the branch).
The intrinsic is lowered to a SI_INIT_WHOLE_WAVE pseudo, which for now
is expanded in si-wqm (which is where SI_INIT_EXEC is handled too);
however the information that the function was conceptually started in
whole wave mode is stored in the machine function info
(hasInitWholeWave). This will be useful in prolog epilog insertion,
where we can skip saving the inactive lanes for CSRs (since if the
function started with all the lanes active, then there are no inactive
lanes to preserve).
Use GCNPat instead of Custom Lowering to select instructions for
intrinsic llvm.fptrunc.round. "SupportedRoundMode : TImmLeaf" is used as
a predicate to select only when the rounding mode is supported.
"as_hw_round_mode : SDNodeXForm" is developed to translate the round
modes to the corresponding ones that hardware recognizes.
Support AND/OR/XOR true16 and LDEXP true/fake16 format.
These instructions are previously implemented with fake16 profile.
Fixing the implementation.
Added a RA hint so that when using 16bit register in a 32bit
instruction, try to use the register directly without an extra 16bit
move
---------
Co-authored-by: guochen2 <guochen2@amd.com>
isExtractHiElt should return new source register instead of returning
instruction that defines it. Src = MI.getOperand(0).getReg() is not
correct when MI(for example G_UNMERGE_VALUES) defines multiple registers.
Refactor existing code to work with source registers only.
This regresses the arbitrary address space pointer case. Ideally
we could write a pattern that matches a pointer based only on
its size, but using iPTR/iPTRAny seem to not work for this.
This is still relying on the manual code for splitting 64-bit
constants, and handling pointers.
We were missing some of the tablegen patterns for all immediate types,
so this has some side effect DAG path improvements. This also reduces
the diff in the 2 selector outputs.
An appropriately configured image resource descriptor can trigger
image_sample instructions to store outputs directly to a linked memory
location instead of returning to VGPRs.
This is opaque to the backend as instruction encoding is unchanged;
however, a mechanism is require to allow frontends to communicate that
these instructions do not require destination VGPRs and store to memory.
Flagging these as stores means they will not be optimized away.
For unbuffered smem loads, it is illegal for the immediate offset to be
negative if the resulting IOFFSET + (SGPR[Offset] or M0 or zero) is
negative.
New PR of https://github.com/llvm/llvm-project/pull/79553.
Implement GCNSubtarget::checkSubtargetFeatures as a canonical place to
check subtarget features for consistency and diagnose any
inconsistencies. To start with, the implementation just checks that
either wavefrontsize32 or wavefrontsize64 is selected.
checkSubtargetFeatures is called at the start of instruction selection.
This is pretty arbitrary. It is just a convenient point at which we have
access to the subtarget that we're going to use for codegenning a
particular function.
buffer_load instructions that use TFE also need to zero initialize
return values similar to how the image instructions currently work. Add
support for this with standard zero init of all results + zero init of
just TFE flag when enable-prt-strict-null subtarget feature is disabled.
AMDGPUInstructionSelector should no longer attempt to select S1 G_PHIs.
Remove MIR test that attempts to inst-select divergent vcc(S1) G_PHI.
Lane mask merging algorithm for GlobalISel is now responsible for
selecting divergent S1 G_PHIs in AMDGPUGlobalISelDivergenceLowering.
Uniform S1 G_PHIs should be lowered to S32 G_PHIs in reg bank select
pass. In summary S1 G_PHIs should not reach AMDGPUInstructionSelector.
Initialize ModOpcode directly before the loop execution to silence
static analyzer warnings about the usage of an uninitialized variable.
This leads to a redundant assignment of ElV2F16 inside the first loop
execution, but also avoids superfluous emptiness checks of EltsV2F16
after the first execution of the loop.
Implement PhiLoweringHelper for GlobalISel in DivergenceLoweringHelper.
Use machine uniformity analysis to find divergent i1 phis and select
them as lane mask phis in same way SILowerI1Copies select VReg_1 phis.
Note that divergent i1 phis include phis created by LCSSA and all cases
of uses outside of cycle are actually covered by "lowering LCSSA phis".
GlobalISel lane masks are registers with sgpr register class and S1 LLT.
TODO: General goal is that instructions created in this pass are fully
instruction-selected so that selection of lane mask phis is not split
across multiple passes.
patch 3 from: https://github.com/llvm/llvm-project/pull/73337
Implement PhiLoweringHelper for GlobalISel in DivergenceLoweringHelper.
Use machine uniformity analysis to find divergent i1 phis and select
them as lane mask phis in same way SILowerI1Copies select VReg_1 phis.
Note that divergent i1 phis include phis created by LCSSA and all cases
of uses outside of cycle are actually covered by "lowering LCSSA phis".
GlobalISel lane masks are registers with sgpr register class and S1 LLT.
TODO: General goal is that instructions created in this pass are fully
instruction-selected so that selection of lane mask phis is not split
across multiple passes.
patch 3 from: https://github.com/llvm/llvm-project/pull/73337
https://github.com/llvm/llvm-project/pull/70634 has disabled use
of potentially negative scratch offsets, but we can use it on GFX12.
---------
Co-authored-by: Stanislav Mekhanoshin <Stanislav.Mekhanoshin@amd.com>
Implement PhiLoweringHelper for GlobalISel in DivergenceLoweringHelper.
Use machine uniformity analysis to find divergent i1 phis and select
them as lane mask phis in same way SILowerI1Copies select VReg_1 phis.
Note that divergent i1 phis include phis created by LCSSA and all cases
of uses outside of cycle are actually covered by "lowering LCSSA phis".
GlobalISel lane masks are registers with sgpr register class and S1 LLT.
TODO: General goal is that instructions created in this pass are fully
instruction-selected so that selection of lane mask phis is not split
across multiple passes.
patch 3 from: https://github.com/llvm/llvm-project/pull/73337
In order to ensure the correctness of ptr addrspace(7) lowering, we need
a backwards-compatible way to flag buffer intrinsics as volatile that
can't be dropped (unlike metadata).
To acheive this in a backwards-compatible way, we use bit 31 of the
auxilliary immediates of buffer intrinsics as the volatile flag. When
this bit is set, the MachineMemOperand for said intrinsic is marked
volatile. Existing code will ensure that this results in the appropriate
use of flags like glc and dlc.
This commit also harmorizes the handling of the auxilliary immediate for
atomic intrinsics, which new go through extract_cpol like loads and
stores, which masks off the volatile bit.
This is used to select the source modifier (neg) from the immediate
operand. After a follow up commit this will no longer be DOTIU specific.
Co-authored-by: Changpeng Fang <changpeng.fang@amd.com>
