Commit Graph

63 Commits

Author SHA1 Message Date
Dávid Bolvanský cd54c57919 Reland "[Libcalls, Attrs] Annotate libcalls with noundef"
Fixed Clang tests.
2021-02-20 06:18:48 +01:00
Dávid Bolvanský 94d034fb86 Revert "[Libcalls, Attrs] Annotate libcalls with noundef"
This reverts commit 33b0c63775. Bots are failing. Some Clang tests need to be updated too.
2021-02-20 04:18:42 +01:00
Dávid Bolvanský 33b0c63775 [Libcalls, Attrs] Annotate libcalls with noundef
I think we can use here same logic as for nonnull.

strlen(X) - X must be noundef => valid pointer.

for libcalls with size arg, we add noundef only if size is known and greater than 0 - so pointers must be noundef (valid ones)

Reviewed By: jdoerfert, aqjune

Differential Revision: https://reviews.llvm.org/D95122
2021-02-20 04:10:07 +01:00
Juneyoung Lee 9b29610228 Use unary CreateShuffleVector if possible
As mentioned in D93793, there are quite a few places where unary `IRBuilder::CreateShuffleVector(X, Mask)` can be used
instead of `IRBuilder::CreateShuffleVector(X, Undef, Mask)`.
Let's update them.

Actually, it would have been more natural if the patches were made in this order:
(1) let them use unary CreateShuffleVector first
(2) update IRBuilder::CreateShuffleVector to use poison as a placeholder value (D93793)

The order is swapped, but in terms of correctness it is still fine.

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D93923
2020-12-30 22:36:08 +09:00
Juneyoung Lee ae6e89327b Precommit tests that have poison as shufflevector's placeholder
This commit copies existing tests at llvm/Transforms containing
'shufflevector X, undef' and replaces them with 'shufflevector X, poison'.
The new copied tests have *-inseltpoison.ll suffix at its file name
(as db7a2f347f did)
See https://reviews.llvm.org/D93793

Test files listed using

grep -R -E "^[^;]*shufflevector <.*> .*, <.*> undef" | cut -d":" -f1 | uniq

Test files copied & updated using

file_org=llvm/test/Transforms/$1
if [[ "$file_org" = *-inseltpoison.ll ]]; then
  file=$file_org
else
  file=${file_org%.ll}-inseltpoison.ll
  if [ ! -f $file ]; then
    cp $file_org $file
  fi
fi
sed -i -E 's/^([^;]*)shufflevector <(.*)> (.*), <(.*)> undef/\1shufflevector <\2> \3, <\4> poison/g' $file
head -1 $file | grep "Assertions have been autogenerated by utils/update_test_checks.py" -q
if [ "$?" == 1 ]; then
  echo "$file : should be manually updated"
  # The test is manually updated
  exit 1
fi
python3 ./llvm/utils/update_test_checks.py --opt-binary=./build-releaseassert/bin/opt $file
2020-12-29 17:09:31 +09:00
Juneyoung Lee db7a2f347f Precommit transform tests that have poison as insertelement's placeholder
This commit copies existing tests at llvm/Transforms and replaces
'insertelement undef' in those files with 'insertelement poison'.
(see https://reviews.llvm.org/D93586)

Tests listed using this script:

grep -R -E '^[^;]*insertelement <.*> undef,' . | cut -d":" -f1 | uniq |
wc -l

Tests updated:

file_org=llvm/test/Transforms/$1
file=${file_org%.ll}-inseltpoison.ll
cp $file_org $file
sed -i -E 's/^([^;]*)insertelement <(.*)> undef/\1insertelement <\2> poison/g' $file
head -1 $file | grep "Assertions have been autogenerated by utils/update_test_checks.py" -q
if [ "$?" == 1 ]; then
  echo "$file : should be manually updated"
  # I manually updated the script
  exit 1
fi
python3 ./llvm/utils/update_test_checks.py --opt-binary=./build-releaseassert/bin/opt $file
2020-12-24 11:46:17 +09:00
Jay Foad 958130dfda [AMDGPU] Add simplification/combines for llvm.amdgcn.fma.legacy
This follows on from D89558 which added the new intrinsic and D88955
which added similar combines for llvm.amdgcn.fmul.legacy.

Differential Revision: https://reviews.llvm.org/D90028
2020-10-23 16:16:13 +01:00
Jay Foad 86a480e9ce [AMDGPU] Add simplification/combines for llvm.amdgcn.fmul.legacy
Differential Revision: https://reviews.llvm.org/D88955
2020-10-23 09:31:00 +01:00
Matt Arsenault 6a9484f4bf InstCombine: Fix losing load properties in copy-constant-to-alloca
Preserve the alignment and metadata. Atomic loads are skipped for
this, but pass along the properties for consistency.
2020-10-14 12:55:25 -04:00
Matt Arsenault 6da31fa4a6 InstCombine: Fix infinite loop in copy-constant-to-alloca transform
This was broken by 16295d521e, when
instructions started being handled and not just constant
expressions. This was re-inserting an equivalent bitcast to the
original memcpy operand, which made a non-functional IR change on
every iteration.

This also fixes a secondary problem where it was inserting
addrspacecasts which may not have been legal (i.e. it changed the
source address space). Start visiting all pointer users and fail out
if we can't process them. Also start handling the relevant memory
intrinsic users. These cases can be dealt with by running
InferAddressSpaces separately.
2020-10-14 12:55:25 -04:00
Matt Arsenault dc08185ca7 IR: Have byref imply dereferenceable
The langref already states it does, but this wasn't implemented. Also
covers inalloca and preallocated. Also helps fix a dependence on
pointer element types.
2020-09-24 09:57:28 -04:00
Sanjay Patel 8e712807e4 [InstCombine] regenerate test checks; NFC 2020-09-24 09:34:17 -04:00
Sebastian Neubauer 833b3b0d3a [AMDGPU] Add v3f16/v3i16 support to SDag
Fix lowering and instruction selection for v3x16 types
and enable InstCombine to emit them.

This patch only implements it for the selection dag.
GlobalISel tests in GlobalISel/llvm.amdgcn.image.load.1d.d16.ll and
GlobalISel/llvm.amdgcn.image.store.2d.d16.ll still don't work.

Differential Revision: https://reviews.llvm.org/D84420
2020-09-16 17:20:27 +02:00
Sebastian Neubauer b8d1994778 [AMDGPU] Add A16/G16 to InstCombine
When sampling from images with coordinates that only have 16 bit
accuracy, convert the image intrinsic call to use a16 or g16.
This does only happen if the target hardware supports it.

An alternative would be to always apply this combination, independent of
the target hardware and extend 16 bit arguments to 32 bit arguments
during legalization. To me, this sounds like an unnecessary roundtrip
that could prevent some further InstCombine optimizations.

Differential Revision: https://reviews.llvm.org/D85887
2020-08-20 10:51:49 +02:00
Sebastian Neubauer 2a6c871596 [InstCombine] Move target-specific inst combining
For a long time, the InstCombine pass handled target specific
intrinsics. Having target specific code in general passes was noted as
an area for improvement for a long time.

D81728 moves most target specific code out of the InstCombine pass.
Applying the target specific combinations in an extra pass would
probably result in inferior optimizations compared to the current
fixed-point iteration, therefore the InstCombine pass resorts to newly
introduced functions in the TargetTransformInfo when it encounters
unknown intrinsics.
The patch should not have any effect on generated code (under the
assumption that code never uses intrinsics from a foreign target).

This introduces three new functions:
TargetTransformInfo::instCombineIntrinsic
TargetTransformInfo::simplifyDemandedUseBitsIntrinsic
TargetTransformInfo::simplifyDemandedVectorEltsIntrinsic

A few target specific parts are left in the InstCombine folder, where
it makes sense to share code. The largest left-over part in
InstCombineCalls.cpp is the code shared between arm and aarch64.

This allows to move about 3000 lines out from InstCombine to the targets.

Differential Revision: https://reviews.llvm.org/D81728
2020-07-22 15:59:49 +02:00
Sebastian Neubauer 2c659082bd [AMDGPU] Don't combine memory intrs to v3i16
v3i16 and v3f16 currently cannot be legalized and lowered so they should
not be emitted by inst combining.

Moved the check down to still allow extracting 1 or 2 elements via the dmask.

Fixes image intrinsics being combined to return v3x16.

Differential Revision: https://reviews.llvm.org/D84223
2020-07-22 12:44:01 +02:00
Matt Arsenault f0abefaf50 AMDGPU: Add IntrWillReturn to intrinsic definitions
This should probably be implied for all the speculatable ones. I think
the only ones where this plausibly doesn't apply is s_sendmsghalt and
maybe kill.
2020-06-18 15:38:10 -04:00
Matt Arsenault 27fe841aa6 AMDGPU: Refine rcp/rsq intrinsic folding for modern FP rules
We have to assume undef could be an snan, which would need quieting so
returning qnan is safer than undef. Also consider strictfp, and don't
care if the result rounded.
2020-05-23 13:28:36 -04:00
Matt Arsenault 88c20fa3d2 InstCombine: Add constant folding/simplify for amdgcn.ldexp intrinsic
This really belongs in InstructionSimplify since it doesn't introduce
new instructions. Put it in instcombine to avoid increasing the number
of passes considering target intrinsics.

I also noticed that we seem to now be interpreting strictfp attributes
on call sites, so try to handle that.
2020-05-22 08:21:38 -04:00
Matt Arsenault 16295d521e InstCombine: Broaden copy-constant-to-alloca optimization
Consider any constant memory type, not just global constants. AMDGPU
kernel parameters are effectively global constants, but appear as
either reads from an intrinsic derived pointer or function argument.
2020-05-09 16:00:27 -04:00
Sebastian Neubauer 5d3a69feca [AMDGPU] New llvm.amdgcn.ballot intrinsic
Add a new llvm.amdgcn.ballot intrinsic modeled on the ballot function
in GLSL and other shader languages. It returns a bitfield containing the
result of its boolean argument in all active lanes, and zero in all
inactive lanes.

This is intended to replace the existing llvm.amdgcn.icmp and
llvm.amdgcn.fcmp intrinsics after a suitable transition period.

Use the new intrinsic in the atomic optimizer pass.

Differential Revision: https://reviews.llvm.org/D65088
2020-03-31 10:35:39 +02:00
Piotr Sobczak dd7148822b [InstCombine][AMDGPU] Trim components of s_buffer_load
Summary:
Add trimming of unused components of s_buffer_load.

For s_buffer_load and unformatted buffer_load also trim unused
components at the beginning of vector and update offset accordingly.

Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71785
2020-01-30 10:48:25 +01:00
Matt Arsenault 3ef8cdf666 AMDGPU: Do permlane16 vdst_in discard optimization in InstCombine
There's more potential value to discarding the source value earlier,
since we always know the value of the fi/bc bits.
2020-01-16 17:27:53 -05:00
Piotr Sobczak 40b5a0f7c8 Revert "[InstCombine][AMDGPU] Trim more components of *buffer_load"
Revert D70315, as it breaks gfx8 for some reason.

This reverts commit 65f94b3380.
2019-12-18 22:04:44 +01:00
Piotr Sobczak 65f94b3380 [InstCombine][AMDGPU] Trim more components of *buffer_load
Summary:
Add trimming of unused components of s_buffer_load.

Extend trimming of *buffer_load to also include
unused components at the beginning of vectors and update offset.

Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70315
2019-12-17 17:50:07 +01:00
Piotr Sobczak a861c9aef9 [InstCombine] Allow values with multiple users in SimplifyDemandedVectorElts
Summary:
Allow for ignoring the check for a single use in SimplifyDemandedVectorElts
to be able to simplify operands if DemandedElts is known to contain
the union of elements used by all users.
It is a responsibility of a caller of SimplifyDemandedVectorElts to
supply correct DemandedElts.

Simplify a series of extractelement instructions if only a subset of
elements is used.

Reviewers: reames, arsenm, majnemer, nhaehnle

Reviewed By: nhaehnle

Subscribers: wdng, jvesely, nhaehnle, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67345

llvm-svn: 375395
2019-10-21 08:12:47 +00:00
Piotr Sobczak 79769a4475 [InstCombine][AMDGPU] Fix crash with v3i16/v3f16 buffer intrinsics
Summary:
This is something of a workaround to avoid a crash later on in type
legalizer (WidenVectorResult()).
Also added some f16 tests, including a non-working v3f16 case with
a FIXME.

Reviewers: arsenm, tpr, nhaehnle

Reviewed By: arsenm

Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68865

llvm-svn: 374993
2019-10-16 11:14:01 +00:00
Tim Renouf c26b3940c3 [TLI][AMDGPU] AMDPAL does not have library functions
Configure TLI to say that r600/amdgpu does not have any library
functions, such that InstCombine does not do anything like turn sin/cos
into the library function @tan with sufficient fast math flags.

Differential Revision: https://reviews.llvm.org/D67406

Change-Id: I02f907d3e64832117ea9800e9f9285282856e5df
llvm-svn: 371592
2019-09-11 07:26:39 +00:00
Piotr Sobczak 67b979466a [InstCombine][AMDGPU] Simplify tbuffer loads
Summary: Add missing tbuffer loads intrinsics in SimplifyDemandedVectorElts.

Reviewers: arsenm, nhaehnle

Reviewed By: arsenm

Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66926

llvm-svn: 370475
2019-08-30 14:20:04 +00:00
Matt Arsenault 0b7f226311 AMDGPU: Fix test after r366913
llvm-svn: 366916
2019-07-24 16:05:55 +00:00
Hideto Ueno 2d654df763 [AMDGPU][NFC] Simplify test file for amdgcn intrinsics
Summary: Remove unchecked attribute in the call site and use FileCheck String Substitution for `convergent` check.

Reviewers: nhaehnle

Reviewed By: nhaehnle

Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64901

llvm-svn: 366781
2019-07-23 06:48:47 +00:00
Matt Arsenault 6d741f29ec AMDGPU: Fold readlane/readfirstlane calls
llvm-svn: 363587
2019-06-17 17:52:35 +00:00
Matt Arsenault f3b64d80bc AMDGPU: Mark exp/exp.compr as inaccessiblememonly
Should also be marked writeonly, but I think that would require
splitting the version with done set to a separate intrinsic

Test change is only from renumbering the attribute group numbers,
which for some reason the generated check lines consider.

llvm-svn: 363560
2019-06-17 13:52:24 +00:00
Matt Arsenault 492d71cc99 AMDGPU: Fold readlane intrinsics of constants
I'm not 100% sure about this, since I'm worried about IR transforms
that might end up introducing divergence downstream once replaced with
a constant, but I haven't come up with an example yet.

llvm-svn: 363406
2019-06-14 14:51:26 +00:00
Stanislav Mekhanoshin 68a2fef9ae [AMDGPU] gfx1010 wave32 icmp/fcmp intrinsic changes for wave32
Differential Revision: https://reviews.llvm.org/D63301

llvm-svn: 363339
2019-06-13 23:47:36 +00:00
Cameron McInally 5594ee0a3e [NFC][InstCombine] Add unary FNeg tests to AMDGPU/amdgcn-intrinsics.ll
llvm-svn: 362255
2019-05-31 19:12:59 +00:00
Sanjay Patel d91f1dd470 [InstCombine] auto-generate test checks; NFC
llvm-svn: 361181
2019-05-20 17:52:22 +00:00
Eric Christopher cee313d288 Revert "Temporarily Revert "Add basic loop fusion pass.""
The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552
2019-04-17 04:52:47 +00:00
Eric Christopher a863435128 Temporarily Revert "Add basic loop fusion pass."
As it's causing some bot failures (and per request from kbarton).

This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.

llvm-svn: 358546
2019-04-17 02:12:23 +00:00
Tim Renouf 94c163c34e InstCombineSimplifyDemanded: Allow v3 results for AMDGCN buffer and image intrinsics
This helps to avoid the situation where RA spots that only 3 of the
v4f32 result of a load are used, and immediately reallocates the 4th
register for something else, requiring a stall waiting for the load.

Differential Revision: https://reviews.llvm.org/D58906

Change-Id: I947661edfd5715f62361a02b100f14aeeada29aa
llvm-svn: 356768
2019-03-22 15:53:50 +00:00
Matt Arsenault 1d83670dbd AMDGPU: Remove intrinsic operand assert
Before r355981, this was under LLVM_DEBUG. I don't think the assert is
quite right, but this really should be a verifier check. Instcombine
should not be asserting on this sort of thing.

llvm-svn: 356219
2019-03-14 23:45:09 +00:00
Matt Arsenault caf1316f71 IR: Add immarg attribute
This indicates an intrinsic parameter is required to be a constant,
and should not be replaced with a non-constant value.

Add the attribute to all AMDGPU and generic intrinsics that comments
indicate it should apply to. I scanned other target intrinsics, but I
don't see any obvious comments indicating which arguments are intended
to be only immediates.

This breaks one questionable testcase for the autoupgrade. I'm unclear
on whether the autoupgrade is supposed to really handle declarations
which were never valid. The verifier fails because the attributes now
refer to a parameter past the end of the argument list.

llvm-svn: 355981
2019-03-12 21:02:54 +00:00
Nicolai Haehnle a69146e67e [InstCombine] Cleanup the TFE/LWE check in AMDGPU SimplifyDemanded
Summary:
The fix added in r352904 is not quite correct, or rather misleading:

1. When the texfailctrl (TFC) argument was non-constant, the fix assumed
   non-TFE/LWE, which is incorrect.

2. Regardless, this code path cannot even be hit for correct
   TFE/LWE-enabled calls, because those return a struct. Added
   a test case for those for completeness.

Change-Id: I92d314dbc67a2670f6d7adaab765ef45f56a49cf

Reviewers: hliao, dstuttard, arsenm

Subscribers: kzhuravl, jvesely, wdng, yaxunl, tpr, t-tye, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57681

llvm-svn: 353097
2019-02-04 21:24:19 +00:00
Michael Liao 8b323f53eb [InstCombine] Extra null-checking on TFE/LWE support
- If that operand is not ConstantInt, skip enabling TFE/LWE.

Differential Revision: https://reviews.llvm.org/D57539

llvm-svn: 352904
2019-02-01 19:53:44 +00:00
Marek Olsak 33eb4d947d AMDGPU: Add a fast path for icmp.i1(src, false, NE)
Summary:
This allows moving the condition from the intrinsic to the standard ICmp
opcode, so that LLVM can do simplifications on it. The icmp.i1 intrinsic
is an identity for retrieving the SGPR mask.

And we can also get the mask from and i1, or i1, xor i1.

Reviewers: arsenm, nhaehnle

Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, t-tye, llvm-commits

Differential Revision: https://reviews.llvm.org/D52060

llvm-svn: 351150
2019-01-15 02:13:18 +00:00
David Stuttard f77079f892 [AMDGPU] Add support for TFE/LWE in image intrinsics. 2nd try
TFE and LWE support requires extra result registers that are written in the
event of a failure in order to detect that failure case.
The specific use-case that initiated these changes is sparse texture support.

This means that if image intrinsics are used with either option turned on, the
programmer must ensure that the return type can contain all of the expected
results. This can result in redundant registers since the vector size must be a
power-of-2.

This change takes roughly 6 parts:
1. Modify the instruction defs in tablegen to add new instruction variants that
can accomodate the extra return values.
2. Updates to lowerImage in SIISelLowering.cpp to accomodate setting TFE or LWE
(where the bulk of the work for these instruction types is now done)
3. Extra verification code to catch cases where intrinsics have been used but
insufficient return registers are used.
4. Modification to the adjustWritemask optimisation to account for TFE/LWE being
enabled (requires extra registers to be maintained for error return value).
5. An extra pass to zero initialize the error value return - this is because if
the error does not occur, the register is not written and thus must be zeroed
before use. Also added a new (on by default) option to ensure ALL return values
are zero-initialized that is required for sparse texture support.
6. Disable the inst_combine optimization in the presence of tfe/lwe (later TODO
for this to re-enable and handle correctly).

There's an additional fix now to avoid a dmask=0

For an image intrinsic with tfe where all result channels except tfe
were unused, I was getting an image instruction with dmask=0 and only a
single vgpr result for tfe. That is incorrect because the hardware
assumes there is at least one vgpr result, plus the one for tfe.

Fixed by forcing dmask to 1, which gives the desired two vgpr result
with tfe in the second one.

The TFE or LWE result is returned from the intrinsics using an aggregate
type. Look in the test code provided to see how this works, but in essence IR
code to invoke the intrinsic looks as follows:

%v = call {<4 x float>,i32} @llvm.amdgcn.image.load.1d.v4f32i32.i32(i32 15,
                                      i32 %s, <8 x i32> %rsrc, i32 1, i32 0)
%v.vec = extractvalue {<4 x float>, i32} %v, 0
%v.err = extractvalue {<4 x float>, i32} %v, 1

This re-submit of the change also includes a slight modification in
SIISelLowering.cpp to work-around a compiler bug for the powerpc_le
platform that caused a buildbot failure on a previous submission.

Differential revision: https://reviews.llvm.org/D48826

Change-Id: If222bc03642e76cf98059a6bef5d5bffeda38dda


Work around for ppcle compiler bug

Change-Id: Ie284cf24b2271215be1b9dc95b485fd15000e32b
llvm-svn: 351054
2019-01-14 11:55:24 +00:00
Piotr Sobczak deaacc17fe [InstCombine][AMDGPU] Handle more buffer intrinsics
Summary:
Include the following intrinsics in the InsctCombine
simplification:

* amdgcn_raw_buffer_load
* amdgcn_raw_buffer_load_format
* amdgcn_struct_buffer_load
* amdgcn_struct_buffer_load_format

Change-Id: I14deceff74bcb21179baf6aa6e94bf39e7d63d5d

Reviewers: arsenm

Reviewed By: arsenm

Subscribers: arsenm, kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, llvm-commits

Differential Revision: https://reviews.llvm.org/D55882

llvm-svn: 349735
2018-12-20 10:08:18 +00:00
David Stuttard c6603861d8 Revert r347871 "Fix: Add support for TFE/LWE in image intrinsic"
Also revert fix r347876

One of the buildbots was reporting a failure in some relevant tests that I can't
repro or explain at present, so reverting until I can isolate.

llvm-svn: 347911
2018-11-29 20:14:17 +00:00
David Stuttard de02e4b1cc Add support for TFE/LWE in image intrinsics
TFE and LWE support requires extra result registers that are written in the
event of a failure in order to detect that failure case.
The specific use-case that initiated these changes is sparse texture support.

This means that if image intrinsics are used with either option turned on, the
programmer must ensure that the return type can contain all of the expected
results. This can result in redundant registers since the vector size must be a
power-of-2.

This change takes roughly 6 parts:
1. Modify the instruction defs in tablegen to add new instruction variants that
can accomodate the extra return values.
2. Updates to lowerImage in SIISelLowering.cpp to accomodate setting TFE or LWE
(where the bulk of the work for these instruction types is now done)
3. Extra verification code to catch cases where intrinsics have been used but
insufficient return registers are used.
4. Modification to the adjustWritemask optimisation to account for TFE/LWE being
enabled (requires extra registers to be maintained for error return value).
5. An extra pass to zero initialize the error value return - this is because if
the error does not occur, the register is not written and thus must be zeroed
before use. Also added a new (on by default) option to ensure ALL return values
are zero-initialized that is required for sparse texture support.
6. Disable the inst_combine optimization in the presence of tfe/lwe (later TODO
for this to re-enable and handle correctly).

There's an additional fix now to avoid a dmask=0

For an image intrinsic with tfe where all result channels except tfe
were unused, I was getting an image instruction with dmask=0 and only a
single vgpr result for tfe. That is incorrect because the hardware
assumes there is at least one vgpr result, plus the one for tfe.

Fixed by forcing dmask to 1, which gives the desired two vgpr result
with tfe in the second one.

The TFE or LWE result is returned from the intrinsics using an aggregate
type. Look in the test code provided to see how this works, but in essence IR
code to invoke the intrinsic looks as follows:

%v = call {<4 x float>,i32} @llvm.amdgcn.image.load.1d.v4f32i32.i32(i32 15,
                                      i32 %s, <8 x i32> %rsrc, i32 1, i32 0)
%v.vec = extractvalue {<4 x float>, i32} %v, 0
%v.err = extractvalue {<4 x float>, i32} %v, 1

Differential revision: https://reviews.llvm.org/D48826

Change-Id: If222bc03642e76cf98059a6bef5d5bffeda38dda
llvm-svn: 347871
2018-11-29 15:21:13 +00:00
Tom Stellard 28d662164d InstCombine: Avoid introducing poison values when lowering llvm.amdgcn.[us]bfe
Summary:
When the 3rd argument to these intrinsics is zero, lowering them
to shift instructions produces poison values, since we end up with
shift amounts equal to the number of bits in the shifted value.  This
means we can only lower these intrinsics if we can prove that the
3rd argument is not zero.

Reviewers: arsenm

Reviewed By: arsenm

Subscribers: bnieuwenhuizen, jvesely, wdng, nhaehnle, llvm-commits

Differential Revision: https://reviews.llvm.org/D53739

llvm-svn: 346422
2018-11-08 17:57:57 +00:00