Summary:
The old address space inference pass (NVPTXFavorNonGenericAddrSpaces) is unable
to convert the address space of a pointer induction variable. This patch adds a
new pass called NVPTXInferAddressSpaces that overcomes that limitation using a
fixed-point data-flow analysis (see the file header comments for details).
The new pass is experimental and not enabled by default. Users can turn
it on by setting the -nvptx-use-infer-addrspace flag of llc.
Reviewers: jholewinski, tra, jlebar
Subscribers: jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D17965
llvm-svn: 263916
Summary:
Calls sometimes need to be convergent. This is already handled at the
LLVM IR level, but it also needs to be handled at the MI level.
Ideally we'd propagate convergence from instructions, down through the
selection DAG, and into MIs. But this is Hard, and would affect
optimizations in the SDNs -- right now only SDNs with two operands have
any flags at all.
Instead, here's a much simpler hack: Add new opcodes for NVPTX for
convergent calls, and generate these when lowering convergent LLVM
calls.
Reviewers: jholewinski
Subscribers: jholewinski, chandlerc, joker.eph, jhen, tra, llvm-commits
Differential Revision: http://reviews.llvm.org/D17423
llvm-svn: 262373
Summary:
Convergent instrs shouldn't be made control-dependent on other values,
but this is basically the whole point of tail duplication. So just bail
if we see a convergent instruction.
Reviewers: iteratee
Subscribers: jholewinski, jhen, hfinkel, tra, jingyue, llvm-commits
Differential Revision: http://reviews.llvm.org/D17320
llvm-svn: 261540
Summary:
The syncthreads MI is modeled as mayread/maywrite -- convergence doesn't
even come into play here. Nonetheless this property is highly implicit
in the tablegen files, so a test seems appropriate.
Reviewers: jingyue
Subscribers: llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D17319
llvm-svn: 261114
Summary:
Otherwise we'll try to do unsafe optimizations on these MIs, such as
sinking loads below calls.
(I suspect that this is not the only bug in the NVPTX instruction
tablegen files; I need to comb through them.)
Reviewers: jholewinski, tra
Subscribers: jingyue, jhen, llvm-commits
Differential Revision: http://reviews.llvm.org/D17315
llvm-svn: 261113
Summary:
Previously, we would just output "foo = bar" in the assembly, and then
ptxas would choke. Now we die before emitting any invalid code.
Reviewers: echristo
Subscribers: jholewinski, llvm-commits, jhen, tra
Differential Revision: http://reviews.llvm.org/D16490
llvm-svn: 258638
We had two code paths. One would create names like "foo.1" and the other
names like "foo1".
For globals it is important to use "foo.1" to help C++ name demangling.
For locals there is no strong reason to go one way or the other so I
kept the most common mangling (foo1).
llvm-svn: 253804
Note, this was reviewed (and more details are in) http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html
These intrinsics currently have an explicit alignment argument which is
required to be a constant integer. It represents the alignment of the
source and dest, and so must be the minimum of those.
This change allows source and dest to each have their own alignments
by using the alignment attribute on their arguments. The alignment
argument itself is removed.
There are a few places in the code for which the code needs to be
checked by an expert as to whether using only src/dest alignment is
safe. For those places, they currently take the minimum of src/dest
alignments which matches the current behaviour.
For example, code which used to read:
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 500, i32 8, i1 false)
will now read:
call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 8 %dest, i8* align 8 %src, i32 500, i1 false)
For out of tree owners, I was able to strip alignment from calls using sed by replacing:
(call.*llvm\.memset.*)i32\ [0-9]*\,\ i1 false\)
with:
$1i1 false)
and similarly for memmove and memcpy.
I then added back in alignment to test cases which needed it.
A similar commit will be made to clang which actually has many differences in alignment as now
IRBuilder can generate different source/dest alignments on calls.
In IRBuilder itself, a new argument was added. Instead of calling:
CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, /* isVolatile */ false)
you now call
CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, SrcAlign, /* isVolatile */ false)
There is a temporary class (IntegerAlignment) which takes the source alignment and rejects
implicit conversion from bool. This is to prevent isVolatile here from passing its default
parameter to the source alignment.
Note, changes in future can now be made to codegen. I didn't change anything here, but this
change should enable better memcpy code sequences.
Reviewed by Hal Finkel.
llvm-svn: 253511
Summary:
Let NVPTX backend detect integer min and max patterns during isel and emit intrinsics that enable hardware support.
Reviewers: jholewinski, meheff, jingyue
Subscribers: arsenm, llvm-commits, meheff, jingyue, eliben, jholewinski
Differential Revision: http://reviews.llvm.org/D12377
llvm-svn: 246107
Summary:
__shared__ variable may now emit undef value as initializer, do not
throw error on that.
Test Plan: test/CodeGen/NVPTX/global-addrspace.ll
Patch by Xuetian Weng
Reviewers: jholewinski, tra, jingyue
Subscribers: llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D12242
llvm-svn: 245785
For NVPTX, try to use 32-bit division instead of 64-bit division when the dividend and divisor
fit in 32 bits. This speeds up some internal benchmarks significantly. The underlying reason
is that many index computations are carried out in 64-bits but never actually exceed the
capacity of a 32-bit word.
llvm-svn: 244684
Summary:
For example:
s6 = s0*s5;
s2 = s6*s6 + s6;
...
s4 = s6*s3;
We notice that it is possible for s2 is folded to fma (s0, s5, fmul (s6 s6)).
This only happens when Aggressive is true, otherwise hasOneUse() check
already prevents from folding the multiplication with more uses.
Test Plan: test/CodeGen/NVPTX/fma-assoc.ll
Patch by Xuetian Weng
Reviewers: hfinkel, apazos, jingyue, ohsallen, arsenm
Subscribers: arsenm, jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D11855
llvm-svn: 244649
I looked into adding a warning / error for this to FileCheck, but there doesn't
seem to be a good way to avoid it triggering on the instances of it in RUN lines.
llvm-svn: 244481
More specifically, make NVPTXISelDAGToDAG able to emit cached loads (LDG) for pointer induction variables.
Also fix latent bug where LDG was not restricted to kernel functions. I believe that this could not be triggered so far since we do not currently infer that a pointer is global outside a kernel function, and only loads of global pointers are considered for cached loads.
llvm-svn: 244166
Summary:
For example, in
struct S {
int *x;
int *y;
};
__global__ void foo(S s) {
int *b = s.y;
// use b
}
"b" is guaranteed to point to global. NVPTX should emit ld.global/st.global for
accessing "b".
Reviewers: jholewinski
Subscribers: llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D11505
llvm-svn: 243790
Summary:
MCRegAliasIterator only works for physical registers. So, do not run it
on virtual registers.
With this issue fixed, we can resurrect the BranchFolding pass in NVPTX
backend.
Reviewers: jholewinski, bkramer
Subscribers: henryhu, meheff, llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D11174
llvm-svn: 242871
Summary:
[NVPTX] make load on global readonly memory to use ldg
Summary:
As describe in [1], ld.global.nc may be used to load memory by nvcc when
__restrict__ is used and compiler can detect whether read-only data cache
is safe to use.
This patch will try to check whether ldg is safe to use and use them to
replace ld.global when possible. This change can improve the performance
by 18~29% on affected kernels (ratt*_kernel and rwdot*_kernel) in
S3D benchmark of shoc [2].
Patched by Xuetian Weng.
[1] http://docs.nvidia.com/cuda/kepler-tuning-guide/#read-only-data-cache
[2] https://github.com/vetter/shoc
Test Plan: test/CodeGen/NVPTX/load-with-non-coherent-cache.ll
Reviewers: jholewinski, jingyue
Subscribers: jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D11314
llvm-svn: 242713
Summary:
Without this patch, LoopVectorizer in certain cases (see loop-vectorize.ll)
produces code with complex control flow which hurts later optimizations. Since
NVPTX doesn't have vector registers in LLVM's sense
(NVPTXTTI::getRegisterBitWidth(true) == 32), we for now declare no vector
registers to effectively disable loop vectorization.
Reviewers: jholewinski
Subscribers: jingyue, llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D11089
llvm-svn: 241884
Summary:
According to PTX ISA:
For convenience, ld, st, and cvt instructions permit source and destination data operands to be wider than the instruction-type size, so that narrow values may be loaded, stored, and converted using regular-width registers. For example, 8-bit or 16-bit values may be held directly in 32-bit or 64-bit registers when being loaded, stored, or converted to other types and sizes. The operand type checking rules are relaxed for bit-size and integer (signed and unsigned) instruction types; floating-point instruction types still require that the operand type-size matches exactly, unless the operand is of bit-size type.
So, the ISA does not support load with extending/store with truncatation for floating numbers. This is reflected in setting the loadext/truncstore actions to expand in the code for floating numbers, but vectors of floating numbers are not taken care of.
As a result, loading a vector of floats followed by a fp_extend may be combined by DAGCombiner to a extload, and the extload may be lowered to NVPTXISD::LoadV2 with extending information. However, NVPTXISD::LoadV2 does not perform extending, and no extending instructions are inserted. Finally, PTX instructions with mismatched types are generated, like
ld.v2.f32 {%fd3, %fd4}, [%rd2]
This patch adds the correct actions for vectors of floats, so DAGCombiner would not create loads with extending, and correct code is generated.
Patched by Gang Hu.
Test Plan: Test case attached.
Reviewers: jingyue
Reviewed By: jingyue
Subscribers: llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D10876
llvm-svn: 241191
Summary:
Offset of frame index is calculated by NVPTXPrologEpilogPass. Before
that the correct offset of stack objects cannot be obtained, which
leads to wrong offset if there are more than 2 frame objects. This patch
move NVPTXPeephole after NVPTXPrologEpilogPass. Because the frame index
is already replaced by %VRFrame in NVPTXPrologEpilogPass, we check
VRFrame register instead, and try to remove the VRFrame if there
is no usage after NVPTXPeephole pass.
Patched by Xuetian Weng.
Test Plan:
Strengthened test/CodeGen/NVPTX/local-stack-frame.ll to check the
offset calculation based on SP and SPL.
Reviewers: jholewinski, jingyue
Reviewed By: jingyue
Subscribers: jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D10853
llvm-svn: 241185
Summary:
Really check if %SP is not used in other places, instead of checking only exact
one non-dbg use.
Patched by Xuetian Weng.
Test Plan:
@foo4 in test/CodeGen/NVPTX/local-stack-frame.ll, create a case that
SP will appear twice.
Reviewers: jholewinski, jingyue
Reviewed By: jingyue
Subscribers: llvm-commits, sfantao, jholewinski
Differential Revision: http://reviews.llvm.org/D10844
llvm-svn: 241099
Summary:
Some front ends make kernel pointers global already. In that case,
handlePointerParams does nothing.
Test Plan: more tests in lower-kernel-ptr-arg.ll
Reviewers: grosser
Subscribers: jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D10779
llvm-svn: 240849
Summary:
This patch first change the register that holds local address for stack
frame to %SPL. Then the new NVPTXPeephole pass will try to scan the
following pattern
%vreg0<def> = LEA_ADDRi64 <fi#0>, 4
%vreg1<def> = cvta_to_local %vreg0
and transform it into
%vreg1<def> = LEA_ADDRi64 %VRFrameLocal, 4
Patched by Xuetian Weng
Test Plan: test/CodeGen/NVPTX/local-stack-frame.ll
Reviewers: jholewinski, jingyue
Reviewed By: jingyue
Subscribers: eliben, jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D10549
llvm-svn: 240587
Summary:
This is done by first adding two additional instructions to convert the
alloca returned address to local and convert it back to generic. Then
replace all uses of alloca instruction with the converted generic
address. Then we can rely NVPTXFavorNonGenericAddrSpace pass to combine
the generic addresscast and the corresponding Load, Store, Bitcast, GEP
Instruction together.
Patched by Xuetian Weng (xweng@google.com).
Test Plan: test/CodeGen/NVPTX/lower-alloca.ll
Reviewers: jholewinski, jingyue
Reviewed By: jingyue
Subscribers: meheff, broune, eliben, jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D10483
llvm-svn: 239964
The original change broke clang side tests. I will be submitting those momentarily. This change includes post commit feedback on the original change from from Pete Cooper.
Original Submission comments:
If a parameter to a function is known non-null, use the existing parameter attributes to record that fact at the call site. This has no optimization benefit by itself - that I know of - but is an enabling change for http://reviews.llvm.org/D9129.
Differential Revision: http://reviews.llvm.org/D9132
llvm-svn: 239849
If a parameter to a function is known non-null, use the existing parameter attributes to record that fact at the call site. This has no optimization benefit by itself - that I know of - but is an enabling change for http://reviews.llvm.org/D9129.
Differential Revision: http://reviews.llvm.org/D9132
llvm-svn: 239795
Summary:
We used to assume V->RAUW only modifies the operand list of V's user.
However, if V and V's user are Constants, RAUW may replace and invalidate V's
user entirely.
This patch fixes the above issue by letting the caller replace the
operand instead of calling RAUW on Constants.
Test Plan: @nested_const_expr and @rauw in access-non-generic.ll
Reviewers: broune, jholewinski
Reviewed By: broune, jholewinski
Subscribers: jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D10345
llvm-svn: 239435
array of bytes. The generation of this byte arrays was expecting
the host to be little endian, which prevents big endian hosts to be
used in the generation of the PTX code. This patch fixes the
problem by changing the way the bytes are extracted so that it
works for either little and big endian.
llvm-svn: 239412
Summary:
This cleans up most allocas NVPTXLowerKernelArgs emits for byval
parameters.
Test Plan: makes bug21465.ll more stronger to verify no redundant local load/store.
Reviewers: eliben, jholewinski
Reviewed By: eliben, jholewinski
Subscribers: jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D10322
llvm-svn: 239368
Summary:
With this patch, NVPTXLowerKernelArgs converts a kernel pointer argument to a
pointer in the global address space. This change, along with
NVPTXFavorNonGenericAddrSpaces, allows the NVPTX backend to emit ld.global.*
and st.global.* for accessing kernel pointer arguments.
Minor changes:
1. refactor: extract function convertToPointerInAddrSpace
2. fix a bug in the test case in bug21465.ll
Test Plan: lower-kernel-ptr-arg.ll
Reviewers: eliben, meheff, jholewinski
Reviewed By: jholewinski
Subscribers: wengxt, jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D10154
llvm-svn: 239082
