When we had a sequence like:
s1 = VLDRS [r0, 1], Q0<imp-def>
s3 = VLDRS [r0, 2], Q0<imp-use,kill>, Q0<imp-def>
s0 = VLDRS [r0, 0], Q0<imp-use,kill>, Q0<imp-def>
s2 = VLDRS [r0, 4], Q0<imp-use,kill>, Q0<imp-def>
we were gathering the {s0, s1} loads below the s3 load. This is fine,
but confused the verifier since now the s3 load had Q0<imp-use> with
no definition above it.
This should mark such uses <undef> as well. The liveness structure at
the beginning and end of the block is unaffected, and the true sN
definitions should prevent any dodgy reorderings being introduced
elsewhere.
rdar://problem/15124449
llvm-svn: 192344
This patch fixes an old FIXME by creating a MCTargetStreamer interface
and moving the target specific functions for ARM, Mips and PPC to it.
The ARM streamer is still declared in a common place because it is
used from lib/CodeGen/ARMException.cpp, but the Mips and PPC are
completely hidden in the corresponding Target directories.
I will send an email to llvmdev with instructions on how to use this.
llvm-svn: 192181
from struct byval to registers.
We used to pass 0 which means the alignment of PtrVT. Even when the alignment
of the struct is smaller than 4, the LOADs would have alignment of 4, and
further optimizations could combine the LOADs into a ldm, which would
cause crash.
The fix is to pass the alignment of the struct byval.
rdar://problem/15144402
llvm-svn: 192126
The hint instructions ("nop", "yield", etc) are mostly Thumb2-only, but have
been ported across to the v6M architecture. Fortunately, v6M seems to sit
nicely between v6 (thumb-1 only) and v6T2, so we can add a feature for it
fairly easily.
rdar://problem/15144406
llvm-svn: 192097
When MC was first added, targets could use hasRawTextSupport to keep features
working before they were added to the MC interface.
The design goal of MC is to provide an uniform api for printing assembly and
object files. Short of relaxations and other corner cases, a object file is
just another representation of the assembly.
It was never the intention that targets would keep doing things like
if (hasRawTextSupport())
Set flags in one way.
else
Set flags in another way.
When they do that they create two code paths and the object file is no longer
just another representation of the assembly. This also then requires testing
with llc -filetype=obj, which is extremelly brittle.
This patch removes some of these hacks by replacing them with smaller ones.
The ARM flag setting is trivial, so I just moved it to the constructor. For
Mips, the patch adds two temporary hack directives that allow the assembly
to represent the same things as the object file was already able to.
The hope is that the mips developers will replace the hack directives with
the same ones that gas uses and drop the -print-hack-directives flag.
I will also try to implement a target streamer interface, so that we can
move this out of the common code.
In summary, for any new work, two rules of the thumb are
* Don't use "llc -filetype=obj" in tests.
* Don't add calls to hasRawTextSupport.
llvm-svn: 192035
optimizeSelect folds (predicated) copy instructions, it must not ignore
the original register class of the operand when replacing the register
with the copies dest register.
llvm-svn: 191963
The jump doesn't really kill the registers, the following call does but
we never get back anyway.
This avoids some verify-machineinstrs problems when TAILJUMPs are
if-converted.
llvm-svn: 191962
This function-attribute modifies the callee-saved register list and function
epilogue (specifically the return instruction) so that a routine is suitable
for use as an interrupt-handler of the specified type without disrupting
user-mode applications.
rdar://problem/14207019
llvm-svn: 191766
For targets that have instruction itineraries this means no change. Targets
that move over to the new schedule model will use be able the new schedule
module for instruction latencies in the if-converter (the logic is such that if
there is no itineary we will use the new sched model for the latencies).
Before, we queried "TTI->getInstructionLatency()" for the instruction latency
and the extra prediction cost. Now, we query the TargetSchedule abstraction for
the instruction latency and TargetInstrInfo for the extra predictation cost. The
TargetSchedule abstraction will internally call "TTI->getInstructionLatency" if
an itinerary exists, otherwise it will use the new schedule model.
ATTENTION: Out of tree targets!
(I will also send out an email later to LLVMDev)
This means, if your target implements
unsigned getInstrLatency(const InstrItineraryData *ItinData,
const MachineInstr *MI,
unsigned *PredCost);
and returns a value for "PredCost", you now also need to implement
unsigned getPredictationCost(const MachineInstr *MI);
(if your target uses the IfConversion.cpp pass)
radar://15077010
llvm-svn: 191671
As specified in A8.8.72/A8.8.73/A8.8.74 in the ARM ARM, all variants of the ARM LDRD instruction have the following two constraints:
LDRD<c> <Rt>, <Rt2>, ...
(a) Rt must be even-numbered and not r14
(b) Rt2 must be R(t+1)
If those two constraints are not met the result of executing the instruction will be unpredictable.
Constraint (b) was already enforced, this commit adds support for constraint (a).
Fixes rdar://14479793.
llvm-svn: 191520
LDRD<c> <Rt>, <Rt2>, <label>
LDRD<c> <Rt>, <Rt2>, [<Rn>{, #+/-<imm>}]
LDRD<c> <Rt>, <Rt2>, [<Rn>], #+/-<imm>
LDRD<c> <Rt>, <Rt2>, [<Rn>, #+/-<imm>]!
As specified in A8.8.72/A8.8.73 in the ARM ARM, the T1 encoding has a constraint which enforces that Rt != Rt2.
If this constraint is not met the result of executing the instruction will be unpredictable.
Fixes rdar://14479780.
llvm-svn: 191504
Generally, it is desirable to distribute (a + b) * c to a*c + b*c for
ARM with VMLx forwarding, where a, b and c are vectors.
However, for (a + b)*(a + b), distribution will result in one extra
instruction.
With distribution:
x = a + b (add)
y = a * x (mul)
z = y + b * y (mla)
Without distribution:
x = a + b (add)
z = x * x (mul)
This patch checks if a mul is a square of add/sub. If yes, skip
distribution.
llvm-svn: 191410
This is being disabled because it is no longer needed for
performance. It is only used by postRAscheduler which is also planned
for removal, and it is implemented with an out-dated view of register
liveness. It consideres aliases instead of register units, assumes
valid kill flags, and assumes implicit uses on partial register
defs. Kill flags and implicit operands are error prone and impossible
to verify. We should gradually eliminate dependence on them in the
postRA phases.
Targets that still benefit from this should move to the MI
scheduler. If that doesn't solve the problem, then we should add a
hook to regalloc to optimize reload placement.
llvm-svn: 191348
Previously, the DAGISel function WalkChainUsers was spotting that it
had entered already-selected territory by whether a node was a
MachineNode (amongst other things). Since it's fairly common practice
to insert MachineNodes during ISelLowering, this was not the correct
check.
Looking around, it seems that other nodes get their NodeId set to -1
upon selection, so this makes sure the same thing happens to all
MachineNodes and uses that characteristic to determine whether we
should stop looking for a loop during selection.
This should fix PR15840.
llvm-svn: 191165
The 'Deprecated' class allows you to specify a SubtargetFeature that the
instruction is deprecated on.
The 'ComplexDeprecationPredicate' class allows you to define a custom
predicate that is called to check for deprecation.
For example:
ComplexDeprecationPredicate<"MCR">
would mean you would have to define the following function:
bool getMCRDeprecationInfo(MCInst &MI, MCSubtargetInfo &STI,
std::string &Info)
Which returns 'false' for not deprecated, and 'true' for deprecated
and store the warning message in 'Info'.
The MCTargetAsmParser constructor was chaned to take an extra argument of
the MCInstrInfo class, so out-of-tree targets will need to be changed.
llvm-svn: 190598
We were figuring out whether to use tPICADD or PICADD, then just using
tPICADD unconditionally anyway. Oops.
A testcase from someone familiar enough with ELF to produce one would
be appreciated. The existing PIC testcase correctly verifies the .s
generated, but that doesn't catch this bug, which only showed up in
direct-to-object mode.
http://llvm.org/bugs/show_bug.cgi?id=17180
llvm-svn: 190417
We used to generate the compact unwind encoding from the machine
instructions. However, this had the problem that if the user used `-save-temps'
or compiled their hand-written `.s' file (with CFI directives), we wouldn't
generate the compact unwind encoding.
Move the algorithm that generates the compact unwind encoding into the
MCAsmBackend. This way we can generate the encoding whether the code is from a
`.ll' or `.s' file.
<rdar://problem/13623355>
llvm-svn: 190290
Rafael Espindola