We are combining shuffles to bit shifts before unary permutes, which means we can't fold loads plus the destination register is destructive
llvm-svn: 306978
We are combining shuffles to bit shifts before unary permutes, which means we can't fold loads plus the destination register is destructive
The 32-bit shuffles are a bit tricky and will be dealt with in a later patch
llvm-svn: 306977
We are combining shuffles to bit shifts before unary permutes, which means we can't fold loads plus the destination register is destructive
llvm-svn: 306976
This is NFC after rerunning the "update_llc_test_checks.py" tool on the CodeGen X86 tests in order to submit a patch.
Minor differences due to added "End of Function" lines.
Reviewers: zvi
Differential Revision: https://reviews.llvm.org/D34933
llvm-svn: 306973
Summary: Support G_GLOBAL_VALUE operation. For now most of the PIC configurations not implemented yet.
Reviewers: zvi, guyblank
Reviewed By: guyblank
Subscribers: rovka, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D34738
Conflicts:
test/CodeGen/X86/GlobalISel/regbankselect-X86_64.mir
llvm-svn: 306972
Summary:
Support vector type G_UNMERGE_VALUES selection.
For now G_UNMERGE_VALUES marked as legal for any type, so nothing to do in legalizer.
Reviewers: t.p.northover, qcolombet, zvi, guyblank
Reviewed By: guyblank
Subscribers: rovka, kristof.beyls, guyblank, llvm-commits
Differential Revision: https://reviews.llvm.org/D33665
llvm-svn: 306971
As discussed in D34087, rewrite areNonVolatileConsecutiveLoads using
generic checks. Also, propagate missing local handling from there to
BaseIndexOffset checks.
Tests of note:
* test/CodeGen/X86/build-vector* - Improved.
* test/CodeGen/BPF/undef.ll - Improved store alignment allows an
additional store merge
* test/CodeGen/X86/clear_upper_vector_element_bits.ll - This is a
case we already do not handle well. Here, the DAG is improved, but
scheduling causes a code size degradation.
Reviewers: RKSimon, craig.topper, spatel, andreadb, filcab
Subscribers: nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D34472
llvm-svn: 306819
Summary:
Support vector type G_MERGE_VALUES selection. For now G_MERGE_VALUES marked as legal for any type, so nothing to do in legalizer.
Split from https://reviews.llvm.org/D33665
Reviewers: qcolombet, t.p.northover, zvi, guyblank
Reviewed By: guyblank
Subscribers: rovka, kristof.beyls, guyblank, llvm-commits
Differential Revision: https://reviews.llvm.org/D33958
llvm-svn: 306665
CFI instructions that set appropriate cfa offset and cfa register are now
inserted in emitEpilogue() in X86FrameLowering.
Majority of the changes in this patch:
1. Ensure that CFI instructions do not affect code generation.
2. Enable maintaining correct information about cfa offset and cfa register
in a function when basic blocks are reordered, merged, split, duplicated.
These changes are target independent and described below.
Changed CFI instructions so that they:
1. are duplicable
2. are not counted as instructions when tail duplicating or tail merging
3. can be compared as equal
Add information to each MachineBasicBlock about cfa offset and cfa register
that are valid at its entry and exit (incoming and outgoing CFI info). Add
support for updating this information when basic blocks are merged, split,
duplicated, created. Add a verification pass (CFIInfoVerifier) that checks
that outgoing cfa offset and register of predecessor blocks match incoming
values of their successors.
Incoming and outgoing CFI information is used by a late pass
(CFIInstrInserter) that corrects CFA calculation rule for a basic block if
needed. That means that additional CFI instructions get inserted 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.
Patch by Violeta Vukobrat.
Differential Revision: https://reviews.llvm.org/D18046
llvm-svn: 306529
As noted in D34071, there are some IR optimization opportunities that could be
handled by normal IR passes if this expansion wasn't happening so late in CGP.
Regardless of that, it seems wasteful to knowingly produce suboptimal IR here,
so I'm proposing this change:
%s = sub i32 %x, %y
%r = icmp ne %s, 0
=>
%r = icmp ne %x, %y
Changing the predicate to 'eq' mimics what InstCombine would do, so that's just
an efficiency improvement if we decide this expansion should happen sooner.
The fact that the PowerPC backend doesn't eliminate the 'subf.' might be
something for PPC folks to investigate separately.
Differential Revision: https://reviews.llvm.org/D34416
llvm-svn: 306471
•static latency
•number of uOps from which the instructions consists
•all ports used by the instruction
Reviewers:
RKSimon
zvi
aymanmus
m_zuckerman
Differential Revision: https://reviews.llvm.org/D33897
llvm-svn: 306414
[X86][AVX512] Improve lowering of AVX512 compare intrinsics (remove redundant shift left+right instructions).
AVX512 compare instructions return v*i1 types.
In cases where the number of elements in the returned value are less than 8, clang adds zeroes to get a mask of v8i1 type.
Later on it's replaced with CONCAT_VECTORS, which then is lowered to many DAG nodes including insert/extract element and shift right/left nodes.
The fact that AVX512 compare instructions put the result in a k register and zeroes all its upper bits allows us to remove the extra nodes simply by copying the result to the required register class.
When lowering, identify these cases and transform them into an INSERT_SUBVECTOR node (marked legal), then catch this pattern in instructions selection phase and transform it into one avx512 cmp instruction.
Differential Revision: https://reviews.llvm.org/D33188
llvm-svn: 306402
The non-AVX-512 behavior was changed in r248266 to match N1778
(C bindings for IEEE-754 (2008)), which defined the four functions
to not raise the inexact exception ("rint" is still defined as raising
it).
Update the AVX-512 lowering of these functions to match that: it should
not be different.
llvm-svn: 306299
Convert vector increment or decrement to sub/add with an all-ones constant:
add X, <1, 1...> --> sub X, <-1, -1...>
sub X, <1, 1...> --> add X, <-1, -1...>
The all-ones vector constant can be materialized using a pcmpeq instruction that is
commonly recognized as an idiom (has no register dependency), so that's better than
loading a splat 1 constant.
AVX512 uses 'vpternlogd' for 512-bit vectors because there is apparently no better
way to produce 512 one-bits.
The general advantages of this lowering are:
1. pcmpeq has lower latency than a memop on every uarch I looked at in Agner's tables,
so in theory, this could be better for perf, but...
2. That seems unlikely to affect any OOO implementation, and I can't measure any real
perf difference from this transform on Haswell or Jaguar, but...
3. It doesn't look like it from the diffs, but this is an overall size win because we
eliminate 16 - 64 constant bytes in the case of a vector load. If we're broadcasting
a scalar load (which might itself be a bug), then we're replacing a scalar constant
load + broadcast with a single cheap op, so that should always be smaller/better too.
4. This makes the DAG/isel output more consistent - we use pcmpeq already for padd x, -1
and psub x, -1, so we should use that form for +1 too because we can. If there's some
reason to favor a constant load on some CPU, let's make the reverse transform for all
of these cases (either here in the DAG or in a later machine pass).
This should fix:
https://bugs.llvm.org/show_bug.cgi?id=33483
Differential Revision: https://reviews.llvm.org/D34336
llvm-svn: 306289
This is a last fix for the corner case of PR32214. Actually this is not really corner case in general.
We should not do a loop rotation if we create an additional branch due to it.
Consider the case where we have a loop chain H, M, B, C , where
H is header with viable fallthrough from pre-header and exit from the loop
M - some middle block
B - backedge to Header but with exit from the loop also.
C - some cold block of the loop.
Let's H is determined as a best exit. If we do a loop rotation M, B, C, H we can introduce the extra branch.
Let's compute the change in number of branches:
+1 branch from pre-header to header
-1 branch from header to exit
+1 branch from header to middle block if there is such
-1 branch from cold bock to header if there is one
So if C is not a predecessor of H then we introduce extra branch.
This change actually prohibits rotation of the loop if both true
1) Best Exit has next element in chain as successor.
2) Last element in chain is not a predecessor of first element of chain.
Reviewers: iteratee, xur
Reviewed By: iteratee
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D34271
llvm-svn: 306272
Simon Pilgrim