The module flag "debug-info-assignment-tracking" is set by the
declare-to-assign pass to indicate that assignment tracking is enabled. This
patch changes declare-to-assign to only set the flag if it makes a
modification. This lets the compiler avoid doing extra work for no benefit,
such as is currently the case if assignment tracking is requested for a build
with line tables only (-gmlt) or a build without debug info.
Reviewed By: scott.linder
Differential Revision: https://reviews.llvm.org/D144481
Enabling assignment tracking without this patch, a significant amount of
additional compiler run time comes from the RemoveRedundantDbgInstrs call in
InstCombine. This patch reduces compiler run time by choosing better places to
call RemoveRedundantDbgInstrs.
In non-assignment-tracking builds, RemoveRedundantDbgInstrs is called by
InstCombine if LowerDbgDeclare makes a change (i.e. it is _sometimes_
called). In assignment tracking builds LowerDbgDeclare doesn't do anything. We
still need to clean up redundant intrinsics to avoid a large performance hit
due to the number of instructions, so the current approach is to have
InstCombine _always_ call RemoveRedundantDbgInstrs.
Instrumenting the compiler to run RemoveRedundantDbgInstrs after every pass and
dump the numbers and building CTMark/tramp3d-v4 indicates that SROA and
LoopVectorize give us a bigger bang (number removed) for buck (times pass is
run).
The compile time tracker reports that this patch reduces the number of
instructions retired building CTMark projects by an average of 1.1%.
Reviewed By: scott.linder
Differential Revision: https://reviews.llvm.org/D144483
This reverts commit 37eb9d13f891f7656f811516e765b929b169afe0.
Test failures have been fixed:
- ubsan failure fixed by 72eac42f21c0f45a27f3eaaff9364cbb5189b9e4
- warn-unsafe-buffer-usage-fixits-local-var-span.cpp fixed by
03cc52dfd1dbb4a59b479da55e87838fb93d2067 (wasn't related)
- test-output-format.ll failure was spurious, build failed at
https://lab.llvm.org/buildbot/#/builders/54/builds/3545 (b4431b2d945b6fc19b1a55ac6ce969a8e06e1e93)
but passed at
https://lab.llvm.org/buildbot/#/builders/54/builds/3546 (5ae99be0377248c74346096dc475af254a3fc799)
which is before my revert
b4431b2d94...5ae99be037
Original commit message:
Depends on https://reviews.llvm.org/D142861.
Alternative to https://reviews.llvm.org/D137601.
xxHash is much faster than djbHash. This makes a simple Rust test case with a large constant string 10% faster to compile.
Previous attempts at changing this hash function (e.g. https://reviews.llvm.org/D97396) had to be reverted due to breaking tests that depended on iteration order.
No additional tests fail with this patch compared to `main` when running `check-all` with `-DLLVM_ENABLE_PROJECTS="all"` (on a Linux host), so I hope I found everything that needs to be changed.
Differential Revision: https://reviews.llvm.org/D142862
Without this patch, migrateDebugInfo doesn't understand how to handle existing
fragments that are smaller than the to-be-split store. This can occur
if. e.g. a vector store (1 dbg.assign) is split (many dbg.assigns - 1 fragment
for each scalar) and later those stores are re-vectorized (many dbg.assigns),
and then SROA runs on that.
The approach taken in this patch is to drop intrinsics with fragments outside
of the slice.
For example, starting with:
store <2 x float> %v, ptr %dest !DIAssignID !1
call void @llvm.dbg.assign(..., DIExpression(DW_OP_LLVM_fragment, 0, 32), !1, ...)
call void @llvm.dbg.assign(..., DIExpression(DW_OP_LLVM_fragment, 32, 32), !1, ...)
When visiting the slice of bits 0 to 31 we get:
store float %v.extract.0, ptr %dest !DIAssignID !2
call void @llvm.dbg.assign(..., DIExpression(DW_OP_LLVM_fragment, 0, 32), !2, ...)
The other dbg.assign associated with the currently-split store is dropped for
this split part. And visiting bits 32 to 63 we get the following:
store float %v.extract.1, ptr %adjusted.dest !DIAssignID !3
call void @llvm.dbg.assign(..., DIExpression(DW_OP_LLVM_fragment, 32, 32), !3, ...)
I've added two tests that cover this case.
Implementing this meant re-writing the fragment-calculation part of
migrateDebugInfo to work with the absolute offset of the new slice in terms of
the base alloca (instead of the offset of the slice into the new alloca), the
fragment (if any) of the variable associated with the base alloca, and the
fragment associated with the split store. Because we need the offset into the
base alloca for the variables being split, some careful wiring is required for
memory intrinsics due to the fact that memory intrinsics can be split when
either the source or dest allocas are split. In the case where the source
alloca drives the splitting, we need to be careful to pass migrateDebugInfo the
information in relation to the dest alloca.
Reviewed By: StephenTozer
Differential Revision: https://reviews.llvm.org/D143146
AggLoadStoreRewriter splits aggregate loads and stores into scalars (before the
alloca is split up). The new stores and debug intrinsics are already wired up
correctly - we just need to also delete the dbg.assign that is linked to the
split to-be-deleted store too.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D142882
The intrinsics don't add anything to the tests and the tests are easier to
debug without the additional noise.
Some SSA value names have changed as a result of no longer visiting the
intrinsics.
Reviewed By: jryans
Differential Revision: https://reviews.llvm.org/D143141
Depends on https://reviews.llvm.org/D142861.
Alternative to https://reviews.llvm.org/D137601.
xxHash is much faster than djbHash. This makes a simple Rust test case with a large constant string 10% faster to compile.
Previous attempts at changing this hash function (e.g. https://reviews.llvm.org/D97396) had to be reverted due to breaking tests that depended on iteration order.
No additional tests fail with this patch compared to `main` when running `check-all` with `-DLLVM_ENABLE_PROJECTS="all"` (on a Linux host), so I hope I found everything that needs to be changed.
Differential Revision: https://reviews.llvm.org/D142862
Remove LLVM flag -experimental-assignment-tracking. Assignment tracking is
still enabled from Clang with the command line -Xclang
-fexperimental-assignment-tracking which tells Clang to ask LLVM to run the
pass declare-to-assign. That pass converts conventional debug intrinsics to
assignment tracking metadata. With this patch it now also sets a module flag
debug-info-assignment-tracking with the value `i1 true` (using the flag conflict
rule `Max` since enabling assignment tracking on IR that contains only
conventional debug intrinsics should cause no issues).
Update the docs and tests too.
Reviewed By: CarlosAlbertoEnciso
Differential Revision: https://reviews.llvm.org/D142027
IR is now always parsed in opaque pointer mode, unless
-opaque-pointers=0 is explicitly given. There is no automatic
detection of typed pointers anymore.
The -opaque-pointers=0 option is added to any remaining IR tests
that haven't been migrated yet.
Differential Revision: https://reviews.llvm.org/D141912
This copies existing behaviour from other debug intrinsics to `dbg.assign`s.
Reviewed By: scott.linder
Differential Revision: https://reviews.llvm.org/D141140
This patch adds a new function that can be used to check all the
properties, other than the machine values, of a pair of debug values for
equivalence. This is done by folding the "directness" into the
expression, converting the expression to variadic form if it is not
already in that form, and then comparing directly. In a few places which
check whether two debug values are identical to see if their ranges can
be merged, this function will correctly identify cases where two debug
values are expressed differently but have the same meaning, allowing
those ranges to be correctly merged.
Differential Revision: https://reviews.llvm.org/D136173
* This is a recommit of 3c4d2a03968ccf5889bacffe02d6fa2443b0260f,
* which was reverted in 25f01d593ce296078f57e872778b77d074ae5888,
because it exposed a miscompile in PPC backend, which was resolved
in https://reviews.llvm.org/D140089 / cb3f415cd2019df7d14683842198bc4b7a492bc5.
* which was a recommit of cf624b23bc5d5a6161706d1663def49380ff816a,
* which was reverted in 5cfc22cafe3f2465e0bb324f8daba82ffcabd0df,
because the cut-off on the number of vector elements was not low enough,
and it triggered both SDAG SDNode operand number assertions,
5and caused compile time explosions in some cases.
Let's try with something really *REALLY* conservative first,
just to get somewhere, and try to bump it later.
FIXME: should this respect TTI reg width * num vec regs?
Original commit message:
Now, there's a big caveat here - these bytes
are abstract bytes, not the i8 we have in LLVM,
so strictly speaking this is not exactly legal,
see e.g. https://github.com/AliveToolkit/alive2/issues/860
^ the "bytes" "could" have been a pointer,
and loading it as an integer inserts an implicit ptrtoint.
But at the same time,
InstCombine's `InstCombinerImpl::SimplifyAnyMemTransfer()`
would expand a memtransfer of 1/2/4/8 bytes
into integer-typed load+store,
so this isn't exactly a new problem.
Note that in memory, poison is byte-wise,
so we really can't widen elements,
but SROA seems to be inconsistent here.
Fixes#59116.
As per post-commit feedback, DebugInfo owners are not receptive of the
idea of having a single source of truth instead of relying on everyone
to know how to update these tests manually.
This reverts commit 4ff8d1e315bdd26daae8a6928aa46e347fe0d6eb.
This reverts commit a33b40d61c64b95d736f1a0dd537e9087c330304.
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
Split dbg.assign intrinsics into fragments similarly to what SROA already does
for dbg.declares, except that there's many more intrinsics to split. The
function migrateDebugInfo generates new dbg.assigns intrinsic for each part of
a split store.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133296
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
Split dbg.assign intrinsics into fragments similarly to what SROA already does
for dbg.declares, except that there's many more intrinsics to split. The
function migrateDebugInfo generates new dbg.assigns intrinsic for each part of
a split store.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133296
We identify epilogue code by looking for instructions tagged
with FrameDestroy.
A function may have more than one epilogue, e.g., because of early
returns or code duplicated during optimization. We need only track
the current block, and emit epilogie_begin at most once per block.
We reduce the number of entries in the line table by combining
epilogue_begin with other flags instead of emitting a separate
entry just for epilogue_begin.
Reviewed By: dblaikie, aprantl
Differential Revision: https://reviews.llvm.org/D133376
Over the past day or so, i've took a large swing at our tests,
and reduced the number of tests that were still using the old syntax
from ~1800 to just 200.
Left to handle: (as it is seen in this patch)
* Transforms/LSR
* Transforms/CGP
* Transforms/TypePromotion
* Transforms/HardwareLoops
* Analysis/*
* some misc.
I think this is the right point to start actively refusing
to honor the old syntax, except for the old tests,
to prevent the old syntax from creeping back in.
Thus, let's add temporary default-off flag,
and if it is not passed refuse to accept old syntax.
The tests that still need porting are annotated with this flag.
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D139647
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
Split dbg.assign intrinsics into fragments similarly to what SROA already does
for dbg.declares, except that there's many more intrinsics to split. The
function migrateDebugInfo generates new dbg.assigns intrinsic for each part of
a split store.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133296
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
Reviewed By: StephenTozer
Differential Revision: https://reviews.llvm.org/D136255
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
This reduces peak memory overhead by 15% when building CTMark's tramp3d-v4 with
-O2 -g with assignment tracking enabled.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133321
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
The inliner requires two additions:
fixupAssignments - Update inlined instructions' DIAssignID metadata so that
inlined DIAssignID attachments are unique to the inlined instance.
trackInlinedStores - Treat inlined stores to caller-local variables
(i.e. callee stores to argument pointers that point to the caller's allocas) as
assignments. Track them using trackAssignments, which is the same method as is
used by the AssignmentTrackingPass. This means that we're able to detect stale
memory locations due to DSE after inlining. Because the stores are only tracked
_after_ inlining, any DSE or movement of stores _before_ inlining will not be
accounted for. This is an accepted limitation mentioned in the RFC.
One change is also required:
Update CloneBlock to preserve debug use-before-defs. Otherwise the assignments
will be dropped due to having the intrinsic operands replaced with empty
metadata (see use-before-def.ll in this patch and this related discourse post.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133318
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
Update simplifycfg:
sinkLastInstruction - preserve debug use-before-defs.
SpeculativelyExecuteBB - replace the value component of dbg.assign intrinsics
when stores are hoisted and merged using a select, and don't delete them.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133310
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
Most of the updates here are just to ensure DIAssignID attachments are
maintained and propagated correctly.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133307
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
Update the RemoveRedundantDbgInstrs utility to avoid sometimes losing
information when deleting dbg.assign intrinsics.
removeRedundantDbgInstrsUsingBackwardScan - treat dbg.assign intrinsics that
are not linked to any instruction just like dbg.values. That is, in a block of
contiguous debug intrinsics, delete all other than the last definition for a
fragment. Leave linked dbg.assign intrinsics in place.
removeRedundantDbgInstrsUsingForwardScan - Don't delete linked dbg.assign
intrinsics and don't delete the next intrinsic found even if it would otherwise
be eligible for deletion.
remomveUndefDbgAssignsFromEntryBlock - Delete undef and unlinked dbg.assign
intrinsics encountered in the entry block that come before non-undef
non-unlinked intrinsics for the same variable.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133294
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
The SLP-Vectorizer can merge a set of scalar stores into a single vectorized
store. Merge DIAssignID intrinsics from the scalar stores onto the new
vectorized store.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133320
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
This test covers the NFC-for-normal-debug-info change D133303.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133319
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
DeadStoreElimmination shortens stores that are shadowed by later stores such
that the overlapping part of the earlier store is omitted. Insert an unlinked
dbg.assign intrinsic with a variable fragment that describes the omitted part
to signal that that fragment of the variable has a stale value in memory.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133315
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
In an attempt to preserve more info, don't delete dbg.assign intrinsics that
are considered "out of scope" if they're linked to instructions.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133314
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
Merge DIAssignID attachments on stores that are merged and sunk out of
loops. The store may be sunk into multiple exit blocks, and in this case all
the copies of the store get the same DIAssignID.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133313
The Assignment Tracking debug-info feature is outlined in this RFC:
https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir
Maintain and propagate DIAssignID attachments in memcpyopt.
Reviewed By: jmorse
Differential Revision: https://reviews.llvm.org/D133312
