optimize a call to a llvm intrinsic to something that invovles a call to a C
library call, make sure it sets the right calling convention on the call.
e.g.
extern double pow(double, double);
double t(double x) {
return pow(10, x);
}
Compiles to something like this for AAPCS-VFP:
define arm_aapcs_vfpcc double @t(double %x) #0 {
entry:
%0 = call double @llvm.pow.f64(double 1.000000e+01, double %x)
ret double %0
}
declare double @llvm.pow.f64(double, double) #1
Simplify libcall (part of instcombine) will turn the above into:
define arm_aapcs_vfpcc double @t(double %x) #0 {
entry:
%__exp10 = call double @__exp10(double %x) #1
ret double %__exp10
}
declare double @__exp10(double)
The pre-instcombine code works because calls to LLVM builtins are special.
Instruction selection will chose the right calling convention for the call.
However, the code after instcombine is wrong. The call to __exp10 will use
the C calling convention.
I can think of 3 options to fix this.
1. Make "C" calling convention just work since the target should know what CC
is being used.
This doesn't work because each function can use different CC with the "pcs"
attribute.
2. Have Clang add the right CC keyword on the calls to LLVM builtin.
This will work but it doesn't match the LLVM IR specification which states
these are "Standard C Library Intrinsics".
3. Fix simplify libcall so the resulting calls to the C routines will have the
proper CC keyword. e.g.
%__exp10 = call arm_aapcs_vfpcc double @__exp10(double %x) #1
This works and is the solution I implemented here.
Both solutions #2 and #3 would work. After carefully considering the pros and
cons, I decided to implement #3 for the following reasons.
1. It doesn't change the "spec" of the intrinsics.
2. It's a self-contained fix.
There are a couple of potential downsides.
1. There could be other places in the optimizer that is broken in the same way
that's not addressed by this.
2. There could be other calling conventions that need to be propagated by
simplify-libcall that's not handled.
But for now, this is the fix that I'm most comfortable with.
llvm-svn: 203488
* Add masking instructions before loads and stores (in MC layer).
* Add masking instructions after SP changes (in MC layer).
* Forbid loads, stores and SP changes in delay slots (in MI layer).
Differential Revision: http://llvm-reviews.chandlerc.com/D2904
llvm-svn: 203484
The function was making too many assumptions about its input:
1. The NEON_VDUP optimisation was far too aggressive, assuming (I
think) that the input would always be BUILD_VECTOR.
2. We were treating most unknown concats as legal (by returning Op
rather than SDValue()). I think only concats of pairs of vectors are
actually legal.
http://llvm.org/PR19094
llvm-svn: 203450
The grammar for LLVM IR is not well specified in any document but seems
to obey the following rules:
- Attributes which have parenthesized arguments are never preceded by
commas. This form of attribute is the only one which ever has
optional arguments. However, not all of these attributes support
optional arguments: 'thread_local' supports an optional argument but
'addrspace' does not. Interestingly, 'addrspace' is documented as
being a "qualifier". What constitutes a qualifier? I cannot find a
definition.
- Some attributes use a space between the keyword and the value.
Examples of this form are 'align' and 'section'. These are always
preceded by a comma.
- Otherwise, the attribute has no argument. These attributes do not
have a preceding comma.
Sometimes an attribute goes before the instruction, between the
instruction and it's type, or after it's type. 'atomicrmw' has
'volatile' between the instruction and the type while 'call' has 'tail'
preceding the instruction.
With all this in mind, it seems most consistent for 'inalloca' on an
'inalloca' instruction to occur before between the instruction and the
type. Unlike the current formulation, there would be no preceding
comma. The combination 'alloca inalloca' doesn't look particularly
appetizing, perhaps a better spelling of 'inalloca' is down the road.
llvm-svn: 203376
This is the new idiom:
x<<(y&31) | x>>((0-y)&31)
which is recognized as:
x ROTL (y&31)
The change refines matchRotateSub. In
Neg & (OpSize - 1) == (OpSize - Pos) & (OpSize - 1), if Pos is
Pos' & (OpSize - 1) we can just use Pos' instead of Pos.
llvm-svn: 203315
be split and the result type widened.
When the condition of a vselect has to be split it makes no sense widening the
vselect and thereby widening the condition. We end up in an endless loop of
widening (vselect result type) and splitting (condition mask type) doing this.
Instead, split both the condition and the vselect and widen the result.
I ran this over the test suite with i686 and mattr=+sse and saw no regressions.
Fixes PR18036.
llvm-svn: 203311
These are sometimes created by the shrink to boolean optimization in the
globalopt pass.
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
llvm-svn: 203280
This helps the instruction selector to lower an i64 * i64 -> i128
multiplication into a single instruction on targets which support it.
Patch by Manuel Jacob.
llvm-svn: 203230
Sequences of insertelement/extractelements are sometimes used to build
vectorsr; this code tries to put them back together into shuffles, but
could only produce a completely uniform shuffle types (<N x T> from two
<N x T> sources).
This should allow shuffles with different numbers of elements on the
input and output sides as well.
llvm-svn: 203229
The old system was fairly convoluted:
* A temporary label was created.
* A single PROLOG_LABEL was created with it.
* A few MCCFIInstructions were created with the same label.
The semantics were that the cfi instructions were mapped to the PROLOG_LABEL
via the temporary label. The output position was that of the PROLOG_LABEL.
The temporary label itself was used only for doing the mapping.
The new CFI_INSTRUCTION has a 1:1 mapping to MCCFIInstructions and points to
one by holding an index into the CFI instructions of this function.
I did consider removing MMI.getFrameInstructions completelly and having
CFI_INSTRUCTION own a MCCFIInstruction, but MCCFIInstructions have non
trivial constructors and destructors and are somewhat big, so the this setup
is probably better.
The net result is that we don't create temporary labels that are never used.
llvm-svn: 203204
This patch teaches the DAGCombiner how to fold a binary OR between two
shufflevector into a single shuffle vector when possible.
The rules are:
1. fold (or (shuf A, V_0, MA), (shuf B, V_0, MB)) -> (shuf A, B, Mask1)
2. fold (or (shuf A, V_0, MA), (shuf B, V_0, MB)) -> (shuf B, A, Mask2)
The DAGCombiner can take advantage of the fact that OR is commutative and
compute two possible shuffle masks (Mask1 and Mask2) for the resulting
shuffle node.
Before folding a dag according to either rule 1 or 2, DAGCombiner verifies
that the resulting shuffle mask is legal for the target.
DAGCombiner would firstly try to fold according to 1.; If not possible
then it will try to fold according to 2.
If both Mask1 and Mask2 are illegal then we conservatively don't fold
the OR instruction.
llvm-svn: 203156
Summary:
This provides support for CP and DP relative global accesses in inline
asm.
Reviewers: robertlytton
Reviewed By: robertlytton
Differential Revision: http://llvm-reviews.chandlerc.com/D2943
llvm-svn: 203129
for the Cortex-A53 subtarget in the AArch64 backend.
This patch lays the ground work to annotate each AArch64 instruction
(no NEON yet) with a list of SchedReadWrite types. The patch also
provides the Cortex-A53 processor resources, maps those the the default
SchedReadWrites, and provides basic latency. NEON support will be added
in a subsequent patch with proper forwarding logic.
Verification was done by setting the pre-RA scheduler to linearize to
better gauge the effect of the MIScheduler. Even without modeling the
forward logic, the results show a modest improvement for Cortex-A53.
Reviewers: apazos, mcrosier, atrick
Patch by Dave Estes <cestes@codeaurora.org>!
llvm-svn: 203125
This is consistent with GDB ToT and reduces the number of relocations in
(type and compile) units, substantially reducing relocations and debug
size in fission + type units builds.
llvm-svn: 203082
When copying an i1 value into a GPR for a vaarg call, we need to explicitly
zero-extend the i1 value (otherwise an invalid CRBIT -> GPR copy will be
generated).
llvm-svn: 203041
are operations that do not access memory but may be sensitive
to floating-point environment changes. LLVM does not attempt
to model FP environment changes, so this was unnecessarily conservative
and was getting on the way of some optimizations, in particular
SLP vectorization.
llvm-svn: 203037
On cores without fpcvt support, we cannot promote int_to_fp i1 operations,
because there is nothing to promote them to. The most straightforward
implementation of this uses a select to choose between the two possible
resulting floating-point values (and that's what is done here).
llvm-svn: 203015
Before llvm-mc would print it, but llc was assuming that it would produce
another section changing directive before one was needed. That assumption is
false with inline asm.
Fixes PR19049.
Another option would be to always create the section, but in the asm printer
avoid printing sections changes during initialization. That would work, but
* We do use the fact that llvm-mc prints it in testing. The tests can be changed
if needed.
* A quick poll on IRC suggest that most developers prefer the implicit .text to
be printed.
llvm-svn: 203001
Patchpoints already did this. Doing it for stackmaps is a convenience
for the runtime in the event that it needs to scratch register to
patch or perform a runtime call thunk.
Unlike patchpoints, we just assume the AnyRegCC calling
convention. This is the only language and target independent calling
convention specific to stackmaps so makes sense. Although the calling
convention is not currently used to select the scratch registers.
llvm-svn: 202943
selection dag (PR19012)
In X86SelectionDagInfo::EmitTargetCodeForMemcpy we check with MachineFrameInfo
to make sure that ESI isn't used as a base pointer register before we choose to
emit rep movs (which clobbers esi).
The problem is that MachineFrameInfo wouldn't know about dynamic allocas or
inline asm that clobbers the stack pointer until SelectionDAGBuilder has
encountered them.
This patch fixes the problem by checking for such things when building the
FunctionLoweringInfo.
Differential Revision: http://llvm-reviews.chandlerc.com/D2954
llvm-svn: 202930
Unwind info contents were indented at the same level as function table
contents. That's a bit confusing because the unwind info is pointed by
function table. In other places we usually increment indentation depth
by one when dereferncing a pointer.
This patch also removes extraneous newlines between function tables.
llvm-svn: 202879
Previously for:
tail call void inttoptr (i64 65536 to void ()*)() nounwind
We would emit:
bl 65536
The immediate operand of the bl instruction is a relative offset so it is
wrong to use the absolute address here.
llvm-svn: 202860
Summary:
Previously, attempting to extract lanes 2 and 3 would actually extract lane 1.
The MSA CodeGen tests only covered lanes 0 and 1.
Differential Revision: http://llvm-reviews.chandlerc.com/D2935
llvm-svn: 202848
The original code does not work correctly on executable files because the
code is written in such a way that only object files are assumed to be given
to llvm-objdump.
Contents of RuntimeFunction are different between executables and objects. In
executables, fields in RuntimeFunction have actual addresses to unwind info
structures. On the other hand, in object files, the fields have zero value,
but instead there are relocations pointing to the fields, so that Linker will
fill them at link-time.
So, when we are reading an object file, we need to use relocation info to
find the location of unwind info. When executable, we should just look at the
values in RuntimeFunction.
llvm-svn: 202785
for the Cortex-A53 subtarget in the AArch64 backend.
This patch lays the ground work to annotate each AArch64 instruction
(no NEON yet) with a list of SchedReadWrite types. The patch also
provides the Cortex-A53 processor resources, maps those the the default
SchedReadWrites, and provides basic latency. NEON support will be added
in a subsequent patch with proper forwarding logic.
Verification was done by setting the pre-RA scheduler to linearize to
better gauge the effect of the MIScheduler. Even without modeling the
forward logic, the results show a modest improvement for Cortex-A53.
Reviewers: apazos, mcrosier, atrick
Patch by Dave Estes <cestes@codeaurora.org>!
llvm-svn: 202767
DWARF discriminators are used to distinguish multiple control flow paths
on the same source location. When this happens, instructions across
basic block boundaries will share the same debug location.
This pass detects this situation and creates a new lexical scope to one
of the two instructions. This lexical scope is a child scope of the
original and contains a new discriminator value. This discriminator is
then picked up from MCObjectStreamer::EmitDwarfLocDirective to be
written on the object file.
This fixes http://llvm.org/bugs/show_bug.cgi?id=18270.
llvm-svn: 202752
Summary:
Parts of the compiler still believed MSA load/stores have a 16-bit offset when
it is actually 10-bit. Corrected this, and fixed a closely related issue this
uncovered where load/stores with 10-bit and 12-bit offsets (MSA and microMIPS
respectively) could not load/store using offsets from the stack/frame pointer.
They accepted frameindex+offset, but not frameindex by itself.
Reviewers: jacksprat, matheusalmeida
Reviewed By: jacksprat
Differential Revision: http://llvm-reviews.chandlerc.com/D2888
llvm-svn: 202717
This fixes invalid lengths in .debug_aranges on big-endian mips64
(lengths appear to be left-shifted by 32 bits) and in .debug_loc.
Differential Revision: http://llvm-reviews.chandlerc.com/D2517
llvm-svn: 202716
Now that the PowerPC backend can track individual CR bits as first-class
registers, we should also have a way of allocating them for inline asm
statements. Because these registers are only one bit, if an output variable is
implicitly cast to a larger integer size, we'll get an any_extend to that
larger type (this is part of the existing target-independent logic). As a
result, regardless of the size of the output type, only the first bit is
meaningful.
The constraint identifier "wc" has been chosen for this purpose. Although gcc
does not currently support allocating individual CR bits, this identifier
choice has been coordinated with the gcc PowerPC team, and will be marked as
reserved for this purpose in the gcc constraints.md file.
llvm-svn: 202657
This includes instructions that relate to memory access (load/store/GEP), comparison instructions and calls.
Work was done by lama.saba@intel.com.
llvm-svn: 202647
This generalizes the code to eliminate extra truncs/exts around i1 bit
operations to also do the same on PPC64 for i32 bit operations. This eliminates
a fairly prevalent code wart:
int foo(int a) {
return a == 5 ? 7 : 8;
}
On PPC64, because of the extension implied by the ABI, this would generate:
cmplwi 0, 3, 5
li 12, 8
li 4, 7
isel 3, 4, 12, 2
rldicl 3, 3, 0, 32
blr
where the 'rldicl 3, 3, 0, 32', the extension, is completely unnecessary. At
least for the single-BB case (which is all that the DAG combine mechanism can
handle), this unnecessary extension is no longer generated.
llvm-svn: 202600
Inside iterate, we scan backwards then scan forwards in a loop. When iteration
is not zero, the last node was just updated so we can skip it. But when
iteration is zero, we can't skip the last node.
For the testing case, fixing this will save a spill and move register copies
from hot path to cold path.
llvm-svn: 202557
Tools that use the CommandLine library currently exit with an error
when invoked with -version or -help. This is unusual and non-standard,
so we'll fix them to exit successfully instead.
I don't expect that anyone relies on the current behaviour, so this
should be a fairly safe change.
llvm-svn: 202530
* Align targets of indirect jumps to instruction bundle boundaries (in MI layer).
* Add masking instructions before indirect jumps (in MC layer).
Differential Revision: http://llvm-reviews.chandlerc.com/D2847
llvm-svn: 202479
The PPC isel instruction can fold 0 into the first operand (thus eliminating
the need to materialize a zero-containing register when the 'true' result of
the isel is 0). When the isel is fed by a bit register operation that we can
invert, do so as part of the bit-register-operation peephole routine.
llvm-svn: 202469
This change enables tracking i1 values in the PowerPC backend using the
condition register bits. These bits can be treated on PowerPC as separate
registers; individual bit operations (and, or, xor, etc.) are supported.
Tracking booleans in CR bits has several advantages:
- Reduction in register pressure (because we no longer need GPRs to store
boolean values).
- Logical operations on booleans can be handled more efficiently; we used to
have to move all results from comparisons into GPRs, perform promoted
logical operations in GPRs, and then move the result back into condition
register bits to be used by conditional branches. This can be very
inefficient, because the throughput of these CR <-> GPR moves have high
latency and low throughput (especially when other associated instructions
are accounted for).
- On the POWER7 and similar cores, we can increase total throughput by using
the CR bits. CR bit operations have a dedicated functional unit.
Most of this is more-or-less mechanical: Adjustments were needed in the
calling-convention code, support was added for spilling/restoring individual
condition-register bits, and conditional branch instruction definitions taking
specific CR bits were added (plus patterns and code for generating bit-level
operations).
This is enabled by default when running at -O2 and higher. For -O0 and -O1,
where the ability to debug is more important, this feature is disabled by
default. Individual CR bits do not have assigned DWARF register numbers,
and storing values in CR bits makes them invisible to the debugger.
It is critical, however, that we don't move i1 values that have been promoted
to larger values (such as those passed as function arguments) into bit
registers only to quickly turn around and move the values back into GPRs (such
as happens when values are returned by functions). A pair of target-specific
DAG combines are added to remove the trunc/extends in:
trunc(binary-ops(binary-ops(zext(x), zext(y)), ...)
and:
zext(binary-ops(binary-ops(trunc(x), trunc(y)), ...)
In short, we only want to use CR bits where some of the i1 values come from
comparisons or are used by conditional branches or selects. To put it another
way, if we can do the entire i1 computation in GPRs, then we probably should
(on the POWER7, the GPR-operation throughput is higher, and for all cores, the
CR <-> GPR moves are expensive).
POWER7 test-suite performance results (from 10 runs in each configuration):
SingleSource/Benchmarks/Misc/mandel-2: 35% speedup
MultiSource/Benchmarks/Prolangs-C++/city/city: 21% speedup
MultiSource/Benchmarks/MiBench/automotive-susan: 23% speedup
SingleSource/Benchmarks/CoyoteBench/huffbench: 13% speedup
SingleSource/Benchmarks/Misc-C++/Large/sphereflake: 13% speedup
SingleSource/Benchmarks/Misc-C++/mandel-text: 10% speedup
SingleSource/Benchmarks/Misc-C++-EH/spirit: 10% slowdown
MultiSource/Applications/lemon/lemon: 8% slowdown
llvm-svn: 202451
scan the register file for sub- and super-registers.
No functionality change intended.
(Tests are updated because the comments in the assembler output are
different.)
llvm-svn: 202416
If a function returns a large struct by value return the first 4 words
in registers and the rest on the stack in a location reserved by the
caller. This is needed to support the xC language which supports
functions returning an arbitrary number of return values. This is
r202397 reapplied with a fix to avoid an uninitialized read of a member.
llvm-svn: 202414
Summary:
If a function returns a large struct by value return the first 4 words
in registers and the rest on the stack in a location reserved by the
caller. This is needed to support the xC language which supports
functions returning an arbitrary number of return values.
Reviewers: robertlytton
Reviewed By: robertlytton
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D2889
llvm-svn: 202397
Summary:
If the src, dst and size of a memcpy are known to be 4 byte aligned we
can call __memcpy_4() instead of memcpy().
Reviewers: robertlytton
Reviewed By: robertlytton
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D2871
llvm-svn: 202395
Summary:
Fixes an issue where a test attempts to use -mcpu=x86-64 on non-X86-64 targets.
This triggers an assertion in the MIPS backend since it doesn't know what ABI to
use by default for unrecognized processors.
CC: llvm-commits, rafael
Differential Revision: http://llvm-reviews.chandlerc.com/D2877
llvm-svn: 202369
any ranges - this includes CU ranges where we were previously emitting an
end list marker even if we didn't have a list.
Testcase includes a test for line table only code emission as the problem
was noticed while writing this test.
llvm-svn: 202357
If the SI_KILL operand is constant, we can either clear the exec mask if
the operand is negative, or do nothing otherwise.
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
llvm-svn: 202337
any ranges to the list of ranges for the CU as we don't want to emit
them anyway. This ensures that we will still emit ranges if we have
a compile unit compiled with only line tables and one compiled with
full debug info requested (we'll emit for the one with full debug info).
Update testcase metadata accordingly to continue emitting ranges.
llvm-svn: 202333
and update everything accordingly. This can be used to conditionalize
the amount of output in the backend based on the amount of debug
requested/metadata emission scheme by a front end (e.g. clang).
Paired with a commit to clang.
llvm-svn: 202332
This handles pathological cases in which we see 2x increase in spill
code for large blocks (~50k instructions). I don't have a unit test
for this behavior.
Fixes rdar://16072279.
llvm-svn: 202304
The current approach to lower a vsetult is to flip the sign bit of the
operands, swap the operands and then use a (signed) pcmpgt. psubus (unsigned
saturating subtract) can be used to emulate a vsetult more efficiently:
+ case ISD::SETULT: {
+ // If the comparison is against a constant we can turn this into a
+ // setule. With psubus, setule does not require a swap. This is
+ // beneficial because the constant in the register is no longer
+ // destructed as the destination so it can be hoisted out of a loop.
I also enable lowering via psubus in a few other cases where it's clearly
beneficial: setule and setuge if minu/maxu cannot be used.
rdar://problem/14338765
Patch by Adam Nemet <anemet@apple.com>.
llvm-svn: 202301
We should apply fastcc whenever profitable. We can expand this list,
but there are lots of conventions with performance implications that we
don't want to change.
Differential Revision: http://llvm-reviews.chandlerc.com/D2705
llvm-svn: 202293
COFF object files with 0 as string table size are currently rejected. This
prevents us from reading object files written by tools like cvtres that
violate the PECOFF spec and write 0 instead of 4 for the size of an empty
string table.
llvm-svn: 202292
This includes instructions with aggregate operands (insert/extract), instructions with vector operands (insert/extract/shuffle), binary arithmetic and bitwise instructions, conversion instructions and terminators.
Work was done by lama.saba@intel.com.
llvm-svn: 202262
The table argument is always 128-bit (and interpreted as <16 x i8>) so the
extra specifier for it is just clutter.
No user-visible behaviour change, so no tests.
llvm-svn: 202258
Summary:
Fixes an issue where a test attempts to use -mcpu=cortex-a15 on non-ARM targets.
This triggers an assertion on MIPS since it doesn't know what ABI to use by default for
unrecognized processors.
Reviewers: rengolin
Reviewed By: rengolin
CC: llvm-commits, aemerson, rengolin
Differential Revision: http://llvm-reviews.chandlerc.com/D2876
llvm-svn: 202256
the default.
Based on the patch by Matt Arsenault, D1764!
I switched one place to use the more direct pointer type to compute the
desired address space, and I reworked the memcpy rewriting section to
reflect significant refactorings that this patch helped inspire.
Thanks to several of the folks who helped review and improve the patch
as well.
llvm-svn: 202247
to work independently for the slice side and the other side.
This allows us to only compute the minimum of the two when we actually
rewrite to a memcpy that needs to take the minimum, and preserve higher
alignment for one side or the other when rewriting to loads and stores.
This fix was inspired by seeing the result of some refactoring that
makes addrspace handling better.
llvm-svn: 202242
checking in SROA.
The primary change is to just rely on uge for checking that the offset
is within the allocation size. This removes the explicit checks against
isNegative which were terribly error prone (including the reversed logic
that led to PR18615) and prevented us from supporting stack allocations
larger than half the address space.... Ok, so maybe the latter isn't
*common* but it's a silly restriction to have.
Also, we used to try to support a PHI node which loaded from before the
start of the allocation if any of the loaded bytes were within the
allocation. This doesn't make any sense, we have never really supported
loading or storing *before* the allocation starts. The simplified logic
just doesn't care.
We continue to allow loading past the end of the allocation in part to
support cases where there is a PHI and some loads are larger than others
and the larger ones reach past the end of the allocation. We could solve
this a different and more conservative way, but I'm still somewhat
paranoid about this.
llvm-svn: 202224
We need to abort the formation of counter-register-based loops where there are
128-bit integer operations that might become function calls.
llvm-svn: 202192
Now that DataLayout is not a pass, store one in Module.
Since the C API expects to be able to get a char* to the datalayout description,
we have to keep a std::string somewhere. This patch keeps it in Module and also
uses it to represent modules without a DataLayout.
Once DataLayout is mandatory, we should probably move the string to DataLayout
itself since it won't be necessary anymore to represent the special case of a
module without a DataLayout.
llvm-svn: 202190
Variadic functions have an unspecified parameter tag after the last
argument. In IR this is represented as an unspecified parameter in the
subroutine type.
Paired commit with CFE r202185.
rdar://problem/13690847
This re-applies r202184 + a bugfix in DwarfDebug's argument handling.
llvm-svn: 202188
Variadic functions have an unspecified parameter tag after the last
argument. In IR this is represented as an unspecified parameter in the
subroutine type.
Paired commit with CFE.
rdar://problem/13690847
llvm-svn: 202184
The function with uwtable attribute might be visited by the
stack unwinder, thus the link register should be considered
as clobbered after the execution of the branch and link
instruction (i.e. the definition of the machine instruction
can't be ignored) even when the callee function are marked
with noreturn.
llvm-svn: 202165
The behaviour of the XCore's instruction buffer means that the performance
of the same code sequence can differ depending on whether it starts at a 4
byte aligned address or not. Since we don't model the instruction buffer
in the backend we have no way of knowing for sure if it is beneficial to
word align a specific function. However, in the absence of precise
modelling, it is better on balance to word align functions because:
* It makes a fetch-nop while executing the prologue slightly less likely.
* If we don't word align functions then a small perturbation in one
function can have a dramatic knock on effect. If the size of the function
changes it might change the alignment and therefore the performance of
all the functions that happen to follow it in the binary. This butterfly
effect makes it harder to reason about and measure the performance of
code.
llvm-svn: 202163
ordering.
The fundamental problem that we're hitting here is that the use-def
chain ordering is *itself* not a stable thing to be relying on in the
rewriting for SROA. Further, we use a non-stable sort over the slices to
arrange them based on the section of the alloca they're operating on.
With a debugging STL implementation (or different implementations in
stage2 and stage3) this can cause stage2 != stage3.
The specific aspect of this problem fixed in this commit deals with the
rewriting and load-speculation around PHIs and Selects. This, like many
other aspects of the use-rewriting in SROA, is really part of the
"strong SSA-formation" that is doen by SROA where it works very hard to
canonicalize loads and stores in *just* the right way to satisfy the
needs of mem2reg[1]. When we have a select (or a PHI) with 2 uses of the
same alloca, we test that loads downstream of the select are
speculatable around it twice. If only one of the operands to the select
needs to be rewritten, then if we get lucky we rewrite that one first
and the select is immediately speculatable. This can cause the order of
operand visitation, and thus the order of slices to be rewritten, to
change an alloca from promotable to non-promotable and vice versa.
The fix is to defer all of the speculation until *after* the rewrite
phase is done. Once we've rewritten everything, we can accurately test
for whether speculation will work (once, instead of twice!) and the
order ceases to matter.
This also happens to simplify the other subtlety of speculation -- we
need to *not* speculate anything unless the result of speculating will
make the alloca fully promotable by mem2reg. I had a previous attempt at
simplifying this, but it was still pretty horrible.
There is actually already a *really* nice test case for this in
basictest.ll, but on multiple STL implementations and inputs, we just
got "lucky". Fortunately, the test case is very small and we can
essentially build it in exactly the opposite way to get reasonable
coverage in both directions even from normal STL implementations.
llvm-svn: 202092
boundaries.
It is possible to create an ELF executable where symbol from say .text
section 'points' to the address outside the section boundaries. It does
not have a sense to disassemble something outside the section.
Without this fix llvm-objdump prints finite or infinite (depends on
the executable file architecture) number of 'invalid instruction
encoding' warnings.
llvm-svn: 202083
The .error directive is similar to .err in that it will halt assembly if it is
evaluated for assembly. However, it permits a user supplied message to be
rendered.
llvm-svn: 201999
The .ifeqs directive assembles the following code if the quoted string
parameters are equal. The strings must be quoted using double quotes.
llvm-svn: 201998
.align is handled specially on certain targets. .align without any parameters
on ARM indicates a default alignment (4). Handle the special case in the target
parser, but fall back to the generic parser for the normal version.
llvm-svn: 201988
The .ifne directive assembles the following section of code if the argument
expression is non-zero. Effectively, it is equivalent to if.
llvm-svn: 201986
If the strings are not quoted, the first string stops at the first comma, and
the second string stops at the end of the line. Strings which contain
whitespace should be quoted. Unquoted space is to be discarded.
llvm-svn: 201985
The .err directive produces an error whenever it is assembled. This can be
useful for preventing assembly when an unexpected condition occurs.
llvm-svn: 201984
This adds support for the .short and its alias .hword for adding literal values
into the object file. This is similar to the .word directive, however, rather
than inserting a value of 4 bytes, adds a 2-byte value.
llvm-svn: 201968
Offsets past the range of single-slash encoding are encoded as base64,
padded to 6 characters, and prefixed with two slashes. This encoding is
undocumented but used by MSVC.
llvm-svn: 201940
For targeting pecoff, ".def foo" appears before ".short 32".
.def foo;
...
.LCPI0_0:
.short 32
foo:
CHECK-LABEL seeks not from ".short 32" but from the top of the input.
llvm-svn: 201931
shifted mask rather than masking and shifting separately.
The patch adds this transformation to the DAGCombiner:
(shl (and (setcc:i8v16 ...) N01C) N1C) -> (and (setcc:i8v16 ...) N01C<<N1C)
<rdar://problem/16054492>
Patch by Adam Nemet <anemet@apple.com>
llvm-svn: 201906
This interface allows IRObjectFile to be implemented without having dummy
methods for all section and segment related methods.
Both llvm-ar and llvm-nm are changed to use it. Unfortunately the mangler is
still not plugged in since it requires some refactoring to make a Module hold
a DataLayout.
llvm-svn: 201881
Benjamin Kramer