instructions in the legalized DAG, and leverage it to combine long
sequences of instructions to PSHUFB.
Eventually, the other x86-instruction-specific shuffle combines will
probably all be driven out of this routine. But the real motivation is
to detect after we have fully legalized and optimized a shuffle to the
minimal number of x86 instructions whether it is profitable to replace
the chain with a fully generic PSHUFB instruction even though doing so
requires either a load from a constant pool or tying up a register with
the mask.
While the Intel manuals claim it should be used when it replaces 5 or
more instructions (!!!!) my experience is that it is actually very fast
on modern chips, and so I've gon with a much more aggressive model of
replacing any sequence of 3 or more instructions.
I've also taught it to do some basic canonicalization to special-purpose
instructions which have smaller encodings than their generic
counterparts.
There are still quite a few FIXMEs here, and I've not yet implemented
support for lowering blends with PSHUFB (where its power really shines
due to being able to zero out lanes), but this starts implementing real
PSHUFB support even when using the new, fancy shuffle lowering. =]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214042 91177308-0d34-0410-b5e6-96231b3b80d8
The tale starts with r212808 which attempted to fix inversion of the low
and high bits when lowering MUL_LOHI. Sadly, that commit did not include
any positive test cases, and just removed some operations from a test
case where the actual logic being changed isn't fully visible from the
test.
What this commit did was two things. First, it reversed the low and high
results in the formation of the MERGE_VALUES node for the multiple
results. This is entirely correct.
Second it changed the shuffles for extracting the low and high
components from the i64 results of the multiplies to extract them
assuming a big-endian-style encoding of the multiply results. This
second change is wrong. There is no big-endian encoding in x86, the
results of the multiplies are normal v2i64s: when cast to v4i32, the low
i32s are at offsets 0 and 2, and the high i32s are at offsets 1 and 3.
However, the first change wasn't enough to actually fix the bug, which
is (I assume) why the second change was also made. There was another bug
in the MERGE_VALUES formation: we weren't using a VTList, and so were
getting a single result node! When grabbing the *second* result from the
node, we got... well.. colud be anything. I think this *appeared* to
invert things, but had to be causing other problems as well.
Fortunately, I fixed the MERGE_VALUES issue in r213931, so we should
have been fine, right? NOOOPE! Because the core bug was never addressed,
the test in vector-idiv failed when I fixed the MERGE_VALUES node.
Because there are essentially no docs for this node, I had to guess at
how to fix it and tried swapping the operands, restoring the order of
the original code before r212808. While this "fixed" the test case (in
that we produced the write instructions) we were still extracting the
wrong elements of the i64s, and thus PR20355 was still broken.
This commit essentially reverts the big-endian-style extraction part of
r212808 and goes back to the original masks which were correct. Now that
the MERGE_VALUES node formation is also correct, everything works. I've
also included a more detailed test from PR20355 to make sure this stays
fixed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214011 91177308-0d34-0410-b5e6-96231b3b80d8
The clever way to implement signed multiplication with unsigned *is
already implemented* and tested and working correctly. The bug is
somewhere else. Re-investigating.
This will teach me to not scroll far enough to read the code that did
what I thought needed to be done.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214009 91177308-0d34-0410-b5e6-96231b3b80d8
signed multiplication is requested. While there is not a difference in
the *low* half of the result, the *high* half (used specifically to
implement the signed division by these constants) certainly is used. The
test case I've nuked was actively asserting wrong code.
There is a delightful solution to doing signed multiplication even when
we don't have it that Richard Smith has crafted, but I'll add the
machinery back and implement that in a follow-up patch. This at least
restores correctness.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214007 91177308-0d34-0410-b5e6-96231b3b80d8
instructions which happen to have a constant mask.
Currently, this only handles a very narrow set of cases, but those
happen to be the cases that I care about for testing shuffles sanely.
This is a bit trickier than other shuffle instructions because we're
decoding constants out of the constant pool. The current MC layer makes
it completely impossible to inspect a constant pool entry, so we have to
do it at the MI level and attach the comment to the streamer on its way
out. So no joy for disassembling, but it does make test cases and asm
dumps *much* nicer.
Sorry for no test cases, but it didn't really seem that valuable to go
trolling through existing old test cases and updating them. I'll have
lots of testing of this in the upcoming patch for SSSE3 emission in the
new vector shuffle lowering code paths.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213986 91177308-0d34-0410-b5e6-96231b3b80d8
address of the stack guard was being spilled to the stack.
Previously the address of the stack guard would get spilled to the stack if it
was impossible to keep it in a register. This patch introduces a new target
independent node and pseudo instruction which gets expanded post-RA to a
sequence of instructions that load the stack guard value. Register allocator
can now just remat the value when it can't keep it in a register.
<rdar://problem/12475629>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213967 91177308-0d34-0410-b5e6-96231b3b80d8
SDValues, fixing the two bugs left in the regression suite.
The key for both of these was the use a single value type rather than
a VTList which caused an unintentionally single-result merge-value node.
Fix this by getting the appropriate VTList in place.
Doing this exposed that the comments in x86's code abouth how MUL_LOHI
operands are handle is wrong. The bug with the use of out-of-range
result numbers was hiding the bug about the order of operands here (as
best i can tell). There are more places where the code appears to get
this backwards still...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213931 91177308-0d34-0410-b5e6-96231b3b80d8
vector operation legalization with support for custom target lowering
and fallback to expand when it fails, and use this to implement sext and
anyext load lowering for x86 in a more principled way.
Previously, the x86 backend relied on a target DAG combine to "combine
away" sextload and extload nodes prior to legalization, or would expand
them during legalization with terrible code. This is particularly
problematic because the DAG combine relies on running over non-canonical
DAG nodes at just the right time to match several common and important
patterns. It used a combine rather than lowering because we didn't have
good lowering support, and to expose some tricks being employed to more
combine phases.
With this change it becomes a proper lowering operation, the backend
marks that it can lower these nodes, and I've added support for handling
the canonical forms that don't have direct legal representations such as
sextload of a v4i8 -> v4i64 on AVX1. With this change, our test cases
for this behavior continue to pass even after the DAG combiner beigns
running more systematically over every node.
There is some noise caused by this in the test suite where we actually
use vector extends instead of subregister extraction. This doesn't
really seem like the right thing to do, but is unlikely to be a critical
regression. We do regress in one case where by lowering to the
target-specific patterns early we were able to combine away extraneous
legal math nodes. However, this regression is completely addressed by
switching to a widening based legalization which is what I'm working
toward anyways, so I've just switched the test to that mode.
Differential Revision: http://reviews.llvm.org/D4654
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213897 91177308-0d34-0410-b5e6-96231b3b80d8
This patch minimizes the number of nops that must be emitted on X86 to satisfy
stackmap shadow constraints.
To minimize the number of nops inserted, the X86AsmPrinter now records the
size of the most recent stackmap's shadow in the StackMapShadowTracker class,
and tracks the number of instruction bytes emitted since the that stackmap
instruction was encountered. Padding is emitted (if it is required at all)
immediately before the next stackmap/patchpoint instruction, or at the end of
the basic block.
This optimization should reduce code-size and improve performance for people
using the llvm stackmap intrinsic on X86.
<rdar://problem/14959522>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213892 91177308-0d34-0410-b5e6-96231b3b80d8
Frontends are responsible for putting inalloca on parameters that would
be passed in memory and not registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213891 91177308-0d34-0410-b5e6-96231b3b80d8
GCC 4.8 detected a signed compare [-Wsign-compare]. Add a cast for the
destination index. Add an assert to catch a potential overflow however unlikely
it may be.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213878 91177308-0d34-0410-b5e6-96231b3b80d8
When we had a vector_shuffle where we had an input from each vector, we
could miscompile it because we were assuming the input from V2 wouldn't
be moved from where it was on the vector.
Added a test case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213826 91177308-0d34-0410-b5e6-96231b3b80d8
There were still some disassembler bits in lib/MC, but their use of Object
was only visible in the includes they used, not in the symbols.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213808 91177308-0d34-0410-b5e6-96231b3b80d8
The transform to constant fold unary operations with an AND across a
vector comparison applies when the constant is not a splat of a scalar
as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213800 91177308-0d34-0410-b5e6-96231b3b80d8
The folding of unary operations through a vector compare and mask operation
is only safe if the unary operation result is of the same size as its input.
For example, it's not safe for [su]itofp from v4i32 to v4f64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213799 91177308-0d34-0410-b5e6-96231b3b80d8
This chang fully reverts r211771.
That revision added a canonicalization rule which has the potential to causes a
combine-cycle in the target-independent canonicalizing DAG combine.
The plan is to move the logic that forms target specific addsub nodes as part of
the lowering of shuffles.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213736 91177308-0d34-0410-b5e6-96231b3b80d8
Without this, we produce non-extern relocations when targeting older OS X
versions that ld64 can't cope with in the particular context of __eh_frame
sections (who'd want generic relocation-processing anyway?).
This means that an updated linker (ld64 from Xcode 3.2.6 or later) may be
needed when targeting such platforms with a modern version of LLVM, but this is
probably the case anyway and a reasonable requirement.
PR20212, rdar://problem/17544795
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213665 91177308-0d34-0410-b5e6-96231b3b80d8
This patch removes function 'CommuteVectorShuffle' from X86ISelLowering.cpp
and moves its logic into SelectionDAG.cpp as method 'getCommutedVectorShuffles'.
This refactoring is in preperation of an upcoming change to the DAGCombiner.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213503 91177308-0d34-0410-b5e6-96231b3b80d8
Since the result of a SETCC for X86 is 0 or -1 in each lane, we can
move unary operations, in this case [su]int_to_fp through the mask
operation and constant fold the operation away. Generally speaking:
UNARYOP(AND(VECTOR_CMP(x,y), constant))
--> AND(VECTOR_CMP(x,y), constant2)
where constant2 is UNARYOP(constant).
This implements the transform where UNARYOP is [su]int_to_fp.
For example, consider the simple function:
define <4 x float> @foo(<4 x float> %val, <4 x float> %test) nounwind {
%cmp = fcmp oeq <4 x float> %val, %test
%ext = zext <4 x i1> %cmp to <4 x i32>
%result = sitofp <4 x i32> %ext to <4 x float>
ret <4 x float> %result
}
Before this change, the SSE code is generated as:
LCPI0_0:
.long 1 ## 0x1
.long 1 ## 0x1
.long 1 ## 0x1
.long 1 ## 0x1
.section __TEXT,__text,regular,pure_instructions
.globl _foo
.align 4, 0x90
_foo: ## @foo
cmpeqps %xmm1, %xmm0
andps LCPI0_0(%rip), %xmm0
cvtdq2ps %xmm0, %xmm0
retq
After, the code is improved to:
LCPI0_0:
.long 1065353216 ## float 1.000000e+00
.long 1065353216 ## float 1.000000e+00
.long 1065353216 ## float 1.000000e+00
.long 1065353216 ## float 1.000000e+00
.section __TEXT,__text,regular,pure_instructions
.globl _foo
.align 4, 0x90
_foo: ## @foo
cmpeqps %xmm1, %xmm0
andps LCPI0_0(%rip), %xmm0
retq
The cvtdq2ps has been constant folded away and the floating point 1.0f
vector lanes are materialized directly via the ModRM operand of andps.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213342 91177308-0d34-0410-b5e6-96231b3b80d8
Clang tries to check the clobber list but doesn't list segment registers in its
x86 register list. This fixes PR20343.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213303 91177308-0d34-0410-b5e6-96231b3b80d8
There are two parts here. First is to modify tablegen to adjust the encoding
type ENCODING_RM with the scaling factor.
The second is to use the new encoding types to compute the correct
displacement in the decoder.
Fixes <rdar://problem/17608489>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213281 91177308-0d34-0410-b5e6-96231b3b80d8
Passes the computed scaling factor in TSFlags rather than the old attributes.
Also removes the C++ version of computing the scaling factor (MemObjSize)
along with the asserts added by the previous patch.
No functional change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213279 91177308-0d34-0410-b5e6-96231b3b80d8
This does not actually move the logic yet but reimplements it in the Tablegen
language. Then asserts that the new implementation results in the same value.
The next patch will remove the assert and the temporary use of the TSFlags and
remove the C++ implementation.
The formula requires a limited form of the logical left and right operators.
I implemented these with the bit-extract/insert operator (i.e. blah{bits}).
No functional change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213278 91177308-0d34-0410-b5e6-96231b3b80d8
Previously we asserted on this code. Currently compiler-rt doesn't
actually implement any of these new libcalls, but external help is
pretty much the only viable option for LLVM.
I've followed the much more generic "__truncST2" naming, as opposed to
the odd name for f32 -> f16 truncation. This can obviously be changed
later, or overridden by any targets that need to.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213252 91177308-0d34-0410-b5e6-96231b3b80d8
x86 has no native ability to extend an f16 to f64, but the same result
is obtained if we expand it into two separate extensions: f16 -> f32
-> f64.
Unfortunately the same is not true for truncate, so that still results
in a compilation failure.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213251 91177308-0d34-0410-b5e6-96231b3b80d8
This makes the two intrinsics @llvm.convert.from.f16 and
@llvm.convert.to.f16 accept types other than simple "float". This is
only strictly needed for the truncate operation, since otherwise
double rounding occurs and there's no way to represent the strict IEEE
conversion. However, for symmetry we allow larger types in the extend
too.
During legalization, we can expand an "fp16_to_double" operation into
two extends for convenience, but abort when the truncate isn't legal. A new
libcall is probably needed here.
Even after this commit, various target tweaks are needed to actually use the
extended intrinsics. I've put these into separate commits for clarity, so there
are no actual tests of f64 conversion here.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213248 91177308-0d34-0410-b5e6-96231b3b80d8
It turns out that in most cases (the main exception being i1-related
types) once these operations are formed we cannot separate them and
the targets end up having to deal with them whether they want to or
not.
This is not a good situation, and a more reasonable default can be
formed by ackowledging this and having targets leave them as Legal.
Only x86 seems to be affected (other targets don't even try marking
the operation Expand).
Mostly there's no visible change here yet, but it will be useful to
have truly expanded EXTLOADS for MVT::f16 softening support.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213162 91177308-0d34-0410-b5e6-96231b3b80d8
Before this change, method 'isShuffleMaskLegal' didn't know that shuffles
implementing a 'movhlps' operation were perfectly legal for SSE targets.
This patch adds the missing check for 'isMOVHLPSMask' inside method
'isShuffleMaskLegal' to fix the problem.
The reason why it is important to do this is because the DAGCombiner
conservatively avoids combining a pair of shuffles if the resulting shuffle
node has an illegal mask. Before this patch, shuffles with a MOVHLPS mask were
wrongly considered not to be legal. This was the root cause of some poor-code
generation bugs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213137 91177308-0d34-0410-b5e6-96231b3b80d8
There exists a helper function to abstract away the various differences
between ConstantVector, ConstantDataVector, ConstantAggregateZero, etc.
Use it to simplify X86WindowsTargetObjectFile::getSectionForConstant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213104 91177308-0d34-0410-b5e6-96231b3b80d8
Refactoring; no functional changes intended
Removed PostRAScheduler bits from subtargets (X86, ARM).
Added PostRAScheduler bit to MCSchedModel class.
This bit is set by a CPU's scheduling model (if it exists).
Removed enablePostRAScheduler() function from TargetSubtargetInfo and subclasses.
Fixed the existing enablePostMachineScheduler() method to use the MCSchedModel (was just returning false!).
Added methods to TargetSubtargetInfo to allow overrides for AntiDepBreakMode, CriticalPathRCs, and OptLevel for PostRAScheduling.
Added enablePostRAScheduler() function to PostRAScheduler class which queries the subtarget for the above values.
Preserved existing scheduler behavior for ARM, MIPS, PPC, and X86:
a. ARM overrides the CPU's postRA settings by enabling postRA for any non-Thumb or Thumb2 subtarget.
b. MIPS overrides the CPU's postRA settings by enabling postRA for everything.
c. PPC overrides the CPU's postRA settings by enabling postRA for everything.
d. X86 is the only target that actually has postRA specified via sched model info.
Differential Revision: http://reviews.llvm.org/D4217
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213101 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes a gcc warning caused by a typo. A redundant assignment operation was
accidentally used as the third operand of a conditional expression.
No functional change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213061 91177308-0d34-0410-b5e6-96231b3b80d8
