The logic for this combine is almost identical to the logic for a
(sext (sextload x)) combine.
This commit factors out the logic so it can be shared by both combines,
and corrects the SDLoc assigned in the zext version of the combine.
Prior to this patch, for the given test case, we would apply the
location associated with the udiv instruction to instructions which
perform the load.
Part of: llvm.org/PR37262
llvm-svn: 331303
In DAGCombiner, we try to simplify this pattern:
([s|z]ext (load ...))
Conceptually, a new extload which is created while splitting the load
should have the same debug location as the load.
Making this change affects the IROrder of the new load, causing some
test case churn.
In practice, the new location is never different from the location of
the [s|z]ext, at least not during check-llvm or a stage2 build.
Part of: llvm.org/PR37262
Differential Revision: https://reviews.llvm.org/D46156
llvm-svn: 331301
Setting the right SDLoc on a newly-created zextload fixes a line table
bug which resulted in non-linear stepping behavior.
Several backend tests contained CHECK lines which relied on the IROrder
inherited from the wrong SDLoc. This patch breaks that dependence where
feasbile and regenerates test cases where not.
In some cases, changing a node's IROrder may alter register allocation
and spill behavior. This can affect performance. I have chosen not to
prevent this by applying a "known good" IROrder to SDLocs, as this may
hide a more general bug in the scheduler, or cause regressions on other
test inputs.
rdar://33755881, Part of: llvm.org/PR37262
Differential Revision: https://reviews.llvm.org/D45995
llvm-svn: 331300
This patch fixes a bug introduced by revision 330778 (originally reviewed at:
https://reviews.llvm.org/D44782), where function isFrameLoadOpcode returned
the wrong number of bytes read for opcodes VMOVSSrm and VMOVSDrm.
This corrects that mistake, and extends the regression test to catch cases where
the dead stores should be removed.
Patch by Jeremy Morse.
Differential Revision: https://reviews.llvm.org/D46256
llvm-svn: 331252
Summary:
D42479 (rL329525) enabled SDIV combine for pow2 non-splat vector
dividers. But when there is a 1 in a vector, the instruction sequence to
be generated involves shifting a value by the number of its bit widths,
which is undefined
(c64f4dbfe3/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (L6000-L6006)).
Especially, in architectures that do not support vector instructions,
each of element in a vector will be computed separately using scalar
operations, and then the resulting value will be undef for '1' values
in a vector.
(All 1's vector is fine; only vectors mixed with 1 and others will be
affected.)
Reviewers: RKSimon, jgravelle-google
Subscribers: jfb, dschuff, sbc100, jgravelle-google, llvm-commits
Differential Revision: https://reviews.llvm.org/D46161
llvm-svn: 331092
Summary:
Previously the flag intrinsics always used the index instructions even if a mask instruction also exists.
To fix fix this I've created a single ISD node type that returns index, mask, and flags. The SelectionDAG CSE process will merge all flavors of intrinsics with the same inputs to a s ingle node. Then during isel we just have to look at which results are used to know what instruction to generate. If both mask and index are used we'll need to emit two instructions. But for all other cases we can emit a single instruction.
Since I had to do manual isel anyway, I've removed the pseudo instructions and custom inserter code that was working around tablegen limitations with multiple implicit defs.
I've also renamed the recently added sse42.ll test case to sttni.ll since it focuses on that subset of the sse4.2 instructions.
Reviewers: chandlerc, RKSimon, spatel
Reviewed By: chandlerc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D46202
llvm-svn: 331091
Summary:
Currently only the memory size is supported but others can be added as
needed.
narrowScalar for G_LOAD and G_STORE now correctly update the
MachineMemOperand and will refuse to legalize atomics since those need more
careful expansions to maintain atomicity.
Reviewers: ab, aditya_nandakumar, bogner, rtereshin, aemerson, javed.absar
Reviewed By: aemerson
Subscribers: aemerson, rovka, kristof.beyls, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D45466
llvm-svn: 331071
As noted, the attribute name is subject to change once we have
the clang side implemented, but it's clear that we need some
kind of attribute-based predication here based on the discussion
for:
rL330437
llvm-svn: 330951
This is another preliminary step for disabling this transform as
discussed in the post-commit thread for:
rL330437
I'm using one of the names suggested there for the attribute, but
we can fix that up as needed once the clang side of this is sorted
out.
llvm-svn: 330950
instructions.
These have special permission according to the x86 manual to read
unaligned memory, and this folding is done by ICC and GCC as well.
This corrects one of the issues identified in PR37246.
llvm-svn: 330896
comparison instructions (pcmp[ei]stri*).
These will help show improvements from fixes to PR37246.
I've not really covered the mask forms of this intrinsic as I don't have
as good of an intuition about the likely usage patterns there. Happy for
someone to extend this with tests covering the mask form.
llvm-svn: 330895
Debug var, expr and loc were only supported for non-fixed stack objects.
This patch adds the following fields to the "fixedStack:" entries, and
renames the ones from "stack:" to:
* debug-info-variable
* debug-info-expression
* debug-info-location
Differential Revision: https://reviews.llvm.org/D46032
llvm-svn: 330859
Previously we only formed MUL_IMM when we split a constant. This blocked load folding on those cases. We should also form MUL_IMM for 3/5/9 to favor LEA over load folding.
Differential Revision: https://reviews.llvm.org/D46040
llvm-svn: 330850
We were previously prefering ZEXTLOAD over EXTLOAD if it is legal. This triggers during X86's promotion of i16->i32. Not sure about other targets.
Using ZEXTLOAD can prevent folding it to SEXTLOAD later if we were to promote a sign extended operand like we would need for SRA. However, X86 doesn't currently promote i16 SRA. I was looking into doing that which is how I found this issue.
This is also blocking our ability to fold 4 byte aligned EXTLOADs with "loadi32". This is what caused most of the test changes here.
Differential Revision: https://reviews.llvm.org/D45585#inline-402825
llvm-svn: 330781
Previously, _any_ store or load instruction was considered to be
operating on a spill if it had a frameindex as an operand, and thus
was fair game for optimisations such as "StackSlotColoring". This
usually works, except on architectures where spills can be partially
restored, for example on X86 where a spilt vector can have a single
component loaded (zeroing the rest of the target register). This can be
mis-interpreted and the zero extension unsoundly eliminated, see
pr30821.
To avoid this, this commit optionally provides the caller to
isLoadFromStackSlot and isStoreToStackSlot with the number of bytes
spilt/loaded by the given instruction. Optimisations can then determine
that a full spill followed by a partial load (or vice versa), for
example, cannot necessarily be commuted.
Patch by Jeremy Morse!
Differential Revision: https://reviews.llvm.org/D44782
llvm-svn: 330778
The output of update_llc_test_checks.py on this test file has changed,
so the test file should be updated to minimize source changes in future
patches.
The test updates for this file appear to be limited to relaxations of
the form:
-; SSE2-NEXT: movq %rdi, -{{[0-9]+}}(%rsp) # 8-byte Spill
+; SSE2-NEXT: movq %rdi, {{[-0-9]+}}(%r{{[sb]}}p) # 8-byte Spill
This was suggested in https://reviews.llvm.org/D45995.
llvm-svn: 330758
Split off pinsr/pextr and extractps instructions.
(Mostly) fixes PR36887.
Note: It might be worth adding a WriteFInsertLd class as well in the future.
Differential Revision: https://reviews.llvm.org/D45929
llvm-svn: 330714
Summary:
If attribute "use-soft-float"="true" is set then X86ISelLowering.cpp sets
'Promote' action for ISD::SINT_TO_FP operation on type i32.
But 'Promote' action is not proper in this case since lib function
__floatsidf is available for casting from signed int to float type.
Thus Expand action is more suitable here.
The Expand action should be set for ISD::UINT_TO_FP for soft float as well.
If function attribute "use-soft-float"="true" is set then infinite looping
can happen in DAG combining, function visitSINT_TO_FP() replaces SINT_TO_FP
node with UINT_TO_FP node and function combineUIntToFP() replace vice versa in cycle.
The fix prevents it.
Patch by vrybalov
Differential Revision: https://reviews.llvm.org/D45572
llvm-svn: 330711
This patch aims to provide correct dwarf unwind information in function
epilogue for X86.
It consists of two parts. The first part inserts CFI instructions that set
appropriate cfa offset and cfa register in emitEpilogue() in
X86FrameLowering. This part is X86 specific.
The second part is platform independent and ensures that:
* CFI instructions do not affect code generation (they are not counted as
instructions when tail duplicating or tail merging)
* Unwind information remains correct when a function is modified by
different passes. This is done in a late pass by analyzing information
about cfa offset and cfa register in BBs and inserting additional CFI
directives where necessary.
Added CFIInstrInserter pass:
* analyzes each basic block to determine cfa offset and register are valid
at its entry and exit
* verifies that outgoing cfa offset and register of predecessor blocks match
incoming values of their successors
* inserts additional CFI directives at basic block beginning to correct the
rule for calculating CFA
Having CFI instructions in function epilogue can cause incorrect CFA
calculation rule for some basic blocks. This can happen if, due to basic
block reordering, or the existence of multiple epilogue blocks, some of the
blocks have wrong cfa offset and register values set by the epilogue block
above them.
CFIInstrInserter is currently run only on X86, but can be used by any target
that implements support for adding CFI instructions in epilogue.
Patch by Violeta Vukobrat.
Differential Revision: https://reviews.llvm.org/D42848
llvm-svn: 330706
Summary:
The pass is supposed to scalarize such intrinsics if the target does not support
them natively, so if the scalarization does not happen instruction selection
crashes due to inability to lower these intrinsics.
Reviewers: andrew.w.kaylor, craig.topper
Reviewed By: andrew.w.kaylor
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45947
llvm-svn: 330700
Summary:
This is [[ https://bugs.llvm.org/show_bug.cgi?id=37104 | PR37104 ]].
[[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]] will introduce an IR canonicalization that is likely bad for the end assembly.
Previously, `andl`+`andn`/`andps`+`andnps` / `bic`/`bsl` would be generated. (see `@out`)
Now, they would no longer be generated (see `@in`).
So we need to make sure that they are still generated.
If the mask is constant, we do nothing. InstCombine should have unfolded it.
Else, i use `hasAndNot()` TLI hook.
For now, only handle scalars.
https://rise4fun.com/Alive/bO6
----
I *really* don't like the code i wrote in `DAGCombiner::unfoldMaskedMerge()`.
It is super fragile. Is there something like IR Pattern Matchers for this?
Reviewers: spatel, craig.topper, RKSimon, javed.absar
Reviewed By: spatel
Subscribers: andreadb, courbet, kristof.beyls, javed.absar, rengolin, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D45733
llvm-svn: 330646
Summary:
This is [[ https://bugs.llvm.org/show_bug.cgi?id=37104 | PR37104 ]].
[[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]] will introduce an IR canonicalization that is likely bad for the end assembly.
Previously, `andl`+`andn`/`andps`+`andnps` / `bic`/`bsl` would be generated. (see `@out`)
Now, they would no longer be generated (see `@in`).
I'm guessing `llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp` should be able to unfold this.
Reviewers: spatel, craig.topper, RKSimon, javed.absar
Reviewed By: spatel
Subscribers: nemanjai, rengolin, javed.absar, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D45563
llvm-svn: 330645
This helps debug issues where selection-dag assigns the wrong location
to an instruction.
Differential Revision: https://reviews.llvm.org/D45913
llvm-svn: 330618
