As noted in:
https://reviews.llvm.org/D25685
This is the next-to-smallest step needed to enable the ComputeNumSignBits fix in that patch.
In a minor attempt to keep some structure, we're pulling the FP helper over along with its
integer sibling, but clearly we can and should do more refactoring of the similar helper
functions in DAGCombiner and SelectionDAG to simplify and not duplicate functionality.
llvm-svn: 284421
This came up as part of:
https://reviews.llvm.org/D25485
Note that the vector case is missed because ComputeNumSignBits() is deficient for vectors.
llvm-svn: 284395
SelectionDAG::getConstantPool will automatically determine an appropriate alignment if one is not specified. It does this by querying the type's preferred alignment. This can end up creating quite a lot of padding when the preferred alignment for vectors is 128.
In optimize-for-size mode, it makes sense to instead query the ABI type alignment which is often smaller and causes less padding.
llvm-svn: 284381
CodeGenPrepare knows how to move a zext of a load into the same basic block
where the load lives. The goal is to help ISel match a zero-extending load
instead of two separated instructions.
CGP attempts to move a zext computation even if it lives in a basic block that
does not post-dominate the load's basic block. That means, the hoisted zext may
be speculated. Preserving the zext location would hurt the debugging experience
and the quality of sample pgo.
With this patch, when moving a zext near to its associated load, CGP no longer
propagates the zext's debug location. Instead, CGP conservatively reuses the
same debug location for the load and the zext.
An alternative approach would be to assign an artificial line-0 location to the
zext. However we don't want to over-use the 'line-0' for this particular case
because it would have a size cost in the line-table section for no additional
benefit.
Differential Revision: https://reviews.llvm.org/D25611
llvm-svn: 284377
The previous names were both misleading (the MachineLegalizer actually
contained the info tables) and inconsistent with the selector & translator (in
having a "Machine") prefix. This should make everything sensible again.
The only functional change is the name of a couple of command-line options.
llvm-svn: 284287
Eli noted this potential bug in the post-commit thread for:
https://reviews.llvm.org/rL284239
...but I'm not sure how to trigger it, so there's no test case yet.
llvm-svn: 284268
Summary:
The main purpose of this new helper is to enable simplifying operations that
have multiple uses. SimplifyDemandedBits does not handle multiple uses
currently, and this new function makes it possible to optimize:
and v1, v0, 0xffffff
mul24 v2, v1, v1 ; Multiply ignoring high 8-bits.
To:
mul24 v2, v0, v0
Where before this would not be optimized, because v1 has multiple uses.
Reviewers: bogner, arsenm
Subscribers: nhaehnle, wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D24964
llvm-svn: 284266
X86. The pass optimizes as a unit the entire wide load + shuffles pattern
produced by interleaved vectorization. This initial patch optimizes one pattern
(64-bit elements interleaved by a factor of 4). Future patches will generalize
to additional patterns.
Patch by Farhana Aleen
Differential revision: http://reviews.llvm.org/D24681
llvm-svn: 284260
This will be needed by a future commit to support sign/zero extending from v8i8 to v8i64 which requires a sign/zero_extend_vector_inreg to be created which requires v8i8 to be concatenated upto v64i8 and goes through this code.
llvm-svn: 284204
Summary:
This operation is promoted the same way was ISD::BSWAP. This will
prevent a regression in test/Target/AMDGOU/bitreverse.ll when i16
support is implemented.
Reviewers: bogner, hfinkel
Subscribers: hfinkel, wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D25202
llvm-svn: 284163
the X86 subdirectory. Original commit message:
Requires a valid TargetMachine to be passed to the SafeStack pass.
Patch by Michael LeMay
Differential revision: http://reviews.llvm.org/D24896
llvm-svn: 284161
Relax the constraint for empty live-ranges while doing last chance
recoloring. Indeed, those live-ranges do not need an actual color to be
fond for the recoloring to work.
Empty live-range may happen as a result of splitting/spilling.
Unfortunately no test case for in-tree targets.
llvm-svn: 284152
Retrying after upstream changes.
Simplify Consecutive Merge Store Candidate Search
Now that address aliasing is much less conservative, push through
simplified store merging search which only checks for parallel stores
through the chain subgraph. This is cleaner as the separation of
non-interfering loads/stores from the store-merging logic.
Whem merging stores, search up the chain through a single load, and
finds all possible stores by looking down from through a load and a
TokenFactor to all stores visited. This improves the quality of the
output SelectionDAG and generally the output CodeGen (with some
exceptions).
Additional Minor Changes:
1. Finishes removing unused AliasLoad code
2. Unifies the the chain aggregation in the merged stores across
code paths
3. Re-add the Store node to the worklist after calling
SimplifyDemandedBits.
4. Increase GatherAllAliasesMaxDepth from 6 to 18. That number is
arbitrary, but seemed sufficient to not cause regressions in
tests.
This finishes the change Matt Arsenault started in r246307 and
jyknight's original patch.
Many tests required some changes as memory operations are now
reorderable. Some tests relying on the order were changed to use
volatile memory operations
Noteworthy tests:
CodeGen/AArch64/argument-blocks.ll -
It's not entirely clear what the test_varargs_stackalign test is
supposed to be asserting, but the new code looks right.
CodeGen/AArch64/arm64-memset-inline.lli -
CodeGen/AArch64/arm64-stur.ll -
CodeGen/ARM/memset-inline.ll -
The backend now generates *worse* code due to store merging
succeeding, as we do do a 16-byte constant-zero store efficiently.
CodeGen/AArch64/merge-store.ll -
Improved, but there still seems to be an extraneous vector insert
from an element to itself?
CodeGen/PowerPC/ppc64-align-long-double.ll -
Worse code emitted in this case, due to the improved store->load
forwarding.
CodeGen/X86/dag-merge-fast-accesses.ll -
CodeGen/X86/MergeConsecutiveStores.ll -
CodeGen/X86/stores-merging.ll -
CodeGen/Mips/load-store-left-right.ll -
Restored correct merging of non-aligned stores
CodeGen/AMDGPU/promote-alloca-stored-pointer-value.ll -
Improved. Correctly merges buffer_store_dword calls
CodeGen/AMDGPU/si-triv-disjoint-mem-access.ll -
Improved. Sidesteps loading a stored value and
merges two stores
CodeGen/X86/pr18023.ll -
This test has been removed, as it was asserting incorrect
behavior. Non-volatile stores *CAN* be moved past volatile loads,
and now are.
CodeGen/X86/vector-idiv.ll -
CodeGen/X86/vector-lzcnt-128.ll -
It's basically impossible to tell what these tests are actually
testing. But, looks like the code got better due to the memory
operations being recognized as non-aliasing.
CodeGen/X86/win32-eh.ll -
Both loads of the securitycookie are now merged.
CodeGen/AMDGPU/vgpr-spill-emergency-stack-slot-compute.ll -
This test appears to work but no longer exhibits the spill behavior.
Reviewers: arsenm, hfinkel, tstellarAMD, jyknight, nhaehnle
Subscribers: wdng, nhaehnle, nemanjai, arsenm, weimingz, niravd, RKSimon, aemerson, qcolombet, dsanders, resistor, tstellarAMD, t.p.northover, spatel
Differential Revision: https://reviews.llvm.org/D14834
llvm-svn: 284151
Summary: We need a new LLVM intrinsic to implement MS _AddressOfReturnAddress builtin on 64-bit Windows.
Reviewers: majnemer, rnk
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25293
llvm-svn: 284061
Branch folder removes implicit defs if they are the only non-branching
instructions in a block, and the branches do not use the defined registers.
The problem is that in some cases these implicit defs are required for
the liveness information to be correct.
Differential Revision: https://reviews.llvm.org/D25478
llvm-svn: 284036
Add a number of helper functions to match scalar or vector equivalent constant/splat values to allow most of the combine patterns to be used by vectors.
Differential Revision: https://reviews.llvm.org/D25374
llvm-svn: 284015
This combiner breaks debug experience and should not be run when optimizations are disabled.
For example:
int main() {
int j = 0;
j += 2;
if (j == 2)
return 0;
return 5;
}
When debugging this code compiled in /O0, it should be valid to break at line "j+=2;" and edit the value of j. It should change the return value of the function.
Differential Revision: https://reviews.llvm.org/D19268
llvm-svn: 284014
Fixes a crash in the build_vector -> vector_shuffle combine
when the first vector input is twice as wide as the output,
and the second input vector is even wider.
llvm-svn: 283953
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.
In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.
This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.
Issue from previous rollback fixed, and a new test was added for that
case as well. Issue was worklist/scheduling/taildup issue in layout.
Issue from 2nd rollback fixed, with 2 additional tests. Issue was
tail merging/loop info/tail-duplication causing issue with loops that share
a header block.
Issue with early tail-duplication of blocks that branch to a fallthrough
predecessor fixed with test case: tail-dup-branch-to-fallthrough.ll
Differential revision: https://reviews.llvm.org/D18226
llvm-svn: 283934
The non-obvious motivation for adding this fold (which already happens in InstCombine)
is that we want to canonicalize IR towards select instructions and canonicalize DAG
nodes towards boolean math. So we need to recreate some folds in the DAG to handle that
change in direction.
An interesting implementation difference for cases like this is that InstCombine
generally works top-down while the DAG goes bottom-up. That means we need to detect
different patterns. In this case, the SimplifyDemandedBits fold prevents us from
performing a zext to sext fold that would then be recognized as a negation of a sext.
llvm-svn: 283900
This reverts commit r283842.
test/CodeGen/X86/tail-dup-repeat.ll causes and llc crash with our
internal testing. I'll share a link with you.
llvm-svn: 283857
This changes MachineRegisterInfo to be initializes after parsing all
instructions. This is in preparation for upcoming commits that allow the
register class specification on the operand or deduce them from the
MCInstrDesc.
This commit removes the unused feature of having nonsequential register
numbers. This was confusing anyway as the vreg numbers would be
different after parsing when you had "holes" in your numbering.
This patch also introduces the concept of an incomplete virtual
register. An incomplete virtual register may be used during .mir parsing
to construct MachineOperands without knowing the exact register class
(or register bank) yet.
NFC except for some error messages.
Differential Revision: https://reviews.llvm.org/D22397
llvm-svn: 283848
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.
In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.
This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.
Issue from previous rollback fixed, and a new test was added for that
case as well. Issue was worklist/scheduling/taildup issue in layout.
Issue from 2nd rollback fixed, with 2 additional tests. Issue was
tail merging/loop info/tail-duplication causing issue with loops that share
a header block.
Issue with early tail-duplication of blocks that branch to a fallthrough
predecessor fixed with test case: tail-dup-branch-to-fallthrough.ll
Differential revision: https://reviews.llvm.org/D18226
llvm-svn: 283842
Summary:
Previously, when allocating unspillable live ranges, we would never
attempt to split. We would always bail out and try last ditch graph
recoloring.
This patch changes this by attempting to split all live intervals before
performing recoloring.
This fixes LLVM bug PR14879.
I can't add test cases for any backends other than AVR because none of
them have small enough register classes to trigger the bug.
Reviewers: qcolombet
Subscribers: MatzeB
Differential Revision: https://reviews.llvm.org/D25070
llvm-svn: 283838
