The standard function epilog includes a .size directive, but ppc64 uses
an alternate local symbol to tag the actual start of each function.
Until recently, binutils accepted the .size directive as:
.size test1, .Ltmp0-test1
however, using this directive with recent binutils will result in the error:
.size expression for XXX does not evaluate to a constant
so we must use the label which actually tags the start of the function.
llvm-svn: 151200
Affect on SD scheduling and postRA scheduling:
Printing the DAG will display the nodes in top-down topological order.
This matches the order within the MBB and makes my life much easier in general.
Affect on misched:
We don't need to track virtual register uses at all. This is awesome.
I also intend to rely on the SUnit ID as a topo-sort index. So if A < B then we cannot have an edge B -> A.
llvm-svn: 151135
This makes RAFast 4% faster, and it gets rid of the dodgy DenseMap
iteration.
This also revealed that RAFast would sometimes dereference DenseMap
iterators after erasing other elements from the map. That does seem to
work in the current DenseMap implementation, but SparseSet doesn't allow
it.
llvm-svn: 151111
bundles. This method takes a bundle start and an MI being bundled, and makes
the intervals for the MI's operands appear to start/end on the bundle start.
Also fixes some minor cosmetic issues (whitespace, naming convention) in the
HMEditor code.
llvm-svn: 151099
Passes after RegAlloc should be able to rely on MRI->getNumVirtRegs() == 0.
This makes sharing code for pre/postRA passes more robust.
Now, to check if a pass is running before the RA pipeline begins, use MRI->isSSA().
To check if a pass is running after the RA pipeline ends, use !MRI->getNumVirtRegs().
PEI resets virtual regs when it's done scavenging.
PTX will either have to provide its own PEI pass or assign physregs.
llvm-svn: 151032
ecx = mov eax
al = mov ch
The second copy is not a nop because the sub-indices of ecx,ch is not the
same of that of eax/al.
Re-enabled machine-cp.
PR11940
llvm-svn: 151002
MRI keeps track of which physregs have been used. Make sure it gets
updated with all the regmask-clobbered registers.
Delete the closePhysRegsUsed() function which isn't necessary.
llvm-svn: 150830
any changes.
Internally this adds a private inner class HMEditor, to LiveIntervals. HMEditor provides
an API for updating live intervals when code is moved or bundled.
llvm-svn: 150826
This caused miscompilations on out-of-tree targets, and possibly i386 as
well.
I'll find some other way of hoisting %rip-relative loads from loops
containing calls.
llvm-svn: 150816
The existing framework for postra scheduling is library local. We want to keep it that way. Soon we will have a more general MachineScheduler interface. At that time, various bits will be exposed to targets. In the meantime, the VLIWPacketizer wants to use ScheduleDAGInstrs directly, so it needs to wrapped in a PIMPL to avoid exposing it to the target interface.
llvm-svn: 150633
method. This allows the target lowering code to not have to deal with MDNodes.
Also, avoid leaking memory like a sieve by not creating a global variable for
the image info section, but just emitting the code directly.
llvm-svn: 150624
The llc command line options for enabling/disabling passes are local to CodeGen/Passes.cpp. This patch associates those options with standard pass IDs so they work regardless of how the target configures the passes.
A target has two ways of overriding standard passes:
1) Redefine the pass pipeline (override TargetPassConfig::add%Stage)
2) Replace or suppress individiual passes with TargetPassConfig::substitutePass.
In both cases, the command line options associated with the pass override the target default.
For example, say a target wants to disable machine instruction scheduling by default:
- The target calls disablePass(MachineSchedulerID) but otherwise does not override any TargetPassConfig methods.
- Without any llc options, no scheduler is run.
- With -enable-misched, the standard machine scheduler is run and honors the -misched=... flag to select the scheduler variant, which may be used for performance evaluation or testing.
Sorry overridePass is ugly. I haven't thought of a better way without replacing the cl::opt framework. I hope to do that one day...
I haven't figured out why CodeGen uses char& for pass IDs. AnalysisID is much easier to use and less bug prone. I'm using it wherever I can for internal implementation. Maybe later we can change the global pass ID definitions as well.
llvm-svn: 150563
Pretend that regmask interference ends at the 'dead' slot, even when
there is other interference ending at the 'reg' slot of the same
instruction.
llvm-svn: 150531
Only accept register masks when looking for an 'overlapping' def. When
Overlap is not set, the function searches for a proper definition of
Reg.
This means MI->modifiesRegister() considers register masks, but
MI->definesRegister() doesn't.
llvm-svn: 150529
When a physreg is live in to a basic block, look for any instruction in
the block that clobbers the physreg.
The instruction doesn't have to properly redefine the register, any
overlapping clobber is OK.
This slightly changes live ranges when compiling with register masks.
llvm-svn: 150528
The MachO back-end needs to emit the garbage collection flags specified in the
module flags. This is a WIP, so the front-end hasn't been modified to emit these
flags just yet. Documentation and front-end switching to occur soon.
llvm-svn: 150507
that are greater than the vector element type. For example BUILD_VECTOR
of type <1 x i1> with a constant i8 operand.
This patch fixes the assertion.
llvm-svn: 150477
The scheduler will sometimes check the implicit-def list on instructions
to properly handle pre-colored DAG edges.
Also check any register mask operands for physreg clobbers.
llvm-svn: 150428
v8i8 -> v8i32 on AVX machines. The codegen often scalarizes ANY_EXTEND nodes.
The DAGCombiner has two optimizations that can mitigate the problem. First,
if all of the operands of a BUILD_VECTOR node are extracted from an ZEXT/ANYEXT
nodes, then it is possible to create a new simplified BUILD_VECTOR which uses
UNDEFS/ZERO values to eliminate the scalar ZEXT/ANYEXT nodes.
Second, another dag combine optimization lowers BUILD_VECTOR into a shuffle
vector instruction.
In the case of zext v8i8->v8i32 on AVX, a value in an XMM register is to be
shuffled into a wide YMM register.
This patch modifes the second optimization and allows the creation of
shuffle vectors even when the newly generated vector and the original vector
from which we extract the values are of different types.
llvm-svn: 150340
In case the MachineScheduling pass I'm working on doesn't work well
for another target, they can completely override it. This also adds a
hook immediately after the RegAlloc pass to cleanup immediately after
vregs go away. We may want to fold it into the postRA hook later.
llvm-svn: 150298
When using register masks, registers like %rip are clobbered by the
register mask. LICM should still be able to hoist instructions reading
%rip from a loop containing calls.
llvm-svn: 150288
It can be necessary to detach a register mask pointer from its
MachineOperand. This method is convenient for checking clobbered
physregs on a detached bitmask pointer.
llvm-svn: 150261
This makes global live range splitting behave identically with and
without register mask operands.
This is not necessarily the best way of using register masks for live
range splitting. It would be more efficient to first split global live
ranges around calls (i.e., register masks), and reserve the fine grained
per-physreg interference guidance for global live ranges that do not
cross calls.
For now the goal is to produce identical assembly when enabling register
masks.
llvm-svn: 150259
Make them accessible through MCInstrInfo. They are only used for debugging purposes so this doesn't
have an impact on performance. X86MCTargetDesc.o goes from 630K to 461K on x86_64.
llvm-svn: 150245
Creates a configurable regalloc pipeline.
Ensure specific llc options do what they say and nothing more: -reglloc=... has no effect other than selecting the allocator pass itself. This patch introduces a new umbrella flag, "-optimize-regalloc", to enable/disable the optimizing regalloc "superpass". This allows for example testing coalscing and scheduling under -O0 or vice-versa.
When a CodeGen pass requires the MachineFunction to have a particular property, we need to explicitly define that property so it can be directly queried rather than naming a specific Pass. For example, to check for SSA, use MRI->isSSA, not addRequired<PHIElimination>.
CodeGen transformation passes are never "required" as an analysis
ProcessImplicitDefs does not require LiveVariables.
We have a plan to massively simplify some of the early passes within the regalloc superpass.
llvm-svn: 150226
This only adds the interference checks required for correctness.
We still need to take advantage of register masks for the
interference driven live range splitting.
llvm-svn: 150191
Failure to preserve kills was causing LiveIntervals to miss some EFLAGS live
ranges. Unfortunately I've been unable to reduce a good test case yet.
llvm-svn: 150152
I think this was already the intention, but DeadMachineInstructionElim
was accidentally tracking the liveness of reserved registers. Now,
instructions with reserved defs are never deleted.
This prevents the call stack adjustment instructions from getting
deleted when enabling register masks.
llvm-svn: 150116
For simplicity, treat calls with register masks as basic block
boundaries. This means we can't copy propagate callee-saved registers
across calls, but I don't think that is a big deal.
llvm-svn: 150108
Moving toward a uniform style of pass definition to allow easier target configuration.
Globally declare Pass ID.
Globally declare pass initializer.
Use INITIALIZE_PASS consistently.
Add a call to the initializer from CodeGen.cpp.
Remove redundant "createPass" functions and "getPassName" methods.
While cleaning up declarations, cleaned up comments (sorry for large diff).
llvm-svn: 150100
Build an ordered vector of register mask operands (i.e., calls) when
computing live intervals. Provide a checkRegMaskInterference() function
that computes a bit mask of usable registers for a live range.
This is a quick way of determining of a live range crosses any calls,
and restricting it to the callee saved registers if it does.
Previously, we had to discover call clobbers for each candidate register
independently.
llvm-svn: 150077
but with a critical fix to the SelectionDAG code that optimizes copies
from strings into immediate stores: the previous code was stopping reading
string data at the first nul. Address this by adding a new argument to
llvm::getConstantStringInfo, preserving the behavior before the patch.
llvm-svn: 149800
A live range that has an early clobber tied redef now looks like a
normal tied redef, except the early clobber def uses the early clobber
slot.
This is enough to handle any strange interference problems.
llvm-svn: 149769
I don't have a test that fails because of this, but a test case like
CodeGen/X86/2009-12-01-EarlyClobberBug.ll exposes the problem. EAX is
redefined by a tied early clobber operand on inline asm, and the live
range should look like this:
%EAX,inf = [48r,64e:0)[64e,80r:1) 0@48r 1@64e
Previously, the two values got merged:
%EAX,inf = [48r,80r:0) 0@48r
With this bug fixed, the REDEF_BY_EC VNInfo flag is no longer needed.
llvm-svn: 149768
Andy, in a previous commit you made this into an ImmutablePass so that you could
add it to the PassManager, then in the next commit you left it a Pass but
removed the code that added it to the PM. If you do add it to the PM then the PM
should take care of deleting it, but it's also true that nothing in codegen
needs this object to exist after it's done its work here. It's not clear to me
which design you want; this should likely either cease to be a Pass or be added
to the PM where other parts of CodeGen will request it.
llvm-svn: 149765
If a value is defined by a COPY, that instuction can easily and cheaply
be found by getInstructionFromIndex(VNI->def).
This reduces the size of VNInfo from 24 to 16 bytes, and improves
llc compile time by 3%.
llvm-svn: 149763
Passes prior to instructon selection are now split into separate configurable stages.
Header dependencies are simplified.
The bulk of this diff is simply removal of the silly DisableVerify flags.
Sorry for the target header churn. Attempting to stabilize them.
llvm-svn: 149754
Calls that use register mask operands don't have implicit defs for
returned values. The register mask operand handles the call clobber,
but it always behaves like a set of dead defs.
Add live implicit defs for any implicitly defined physregs that are
actually used.
llvm-svn: 149715
SelectionDAG has 4 different ways of passing physreg defs to users.
Collect all of the uses at the same time, and pass all of them to
MI->setPhysRegsDeadExcept() to mark the remaining defs dead.
The setPhysRegsDeadExcept() function will soon add the required
implicit-defs to instructions with register mask operands.
llvm-svn: 149708
In this patch we optimize this pattern and convert the sequence into extract op of a narrow type.
This allows the BUILD_VECTOR dag optimizations to construct efficient shuffle operations in many cases.
llvm-svn: 149692
Allows command line overrides to be centralized in LLVMTargetMachine.cpp.
LLVMTargetMachine can intercept common passes and give precedence to command line overrides.
Allows adding "internal" target configuration options without touching TargetOptions.
Encapsulates the PassManager.
Provides a good point to initialize all CodeGen passes so that Pass ID's can be used in APIs.
Allows modifying the target configuration hooks without rebuilding the world.
llvm-svn: 149672
needed to emit a 64-bit gp-relative relocation entry. Make changes necessary
for emitting jump tables which have entries with directive .gpdword. This patch
does not implement the parts needed for direct object emission or JIT.
llvm-svn: 149668
more than two adjacent ranges needed to be merged. The new version should be
able to handle an arbitrary sequence of adjancent ranges.
llvm-svn: 149588
This new scheduler plugs into the existing selection DAG scheduling framework. It is a top-down critical path scheduler that tracks register pressure and uses a DFA for pipeline modeling.
Patch by Sergei Larin!
llvm-svn: 149547
The purpose of refactoring is to hide operand roles from SwitchInst user (programmer). If you want to play with operands directly, probably you will need lower level methods than SwitchInst ones (TerminatorInst or may be User). After this patch we can reorganize SwitchInst operands and successors as we want.
What was done:
1. Changed semantics of index inside the getCaseValue method:
getCaseValue(0) means "get first case", not a condition. Use getCondition() if you want to resolve the condition. I propose don't mix SwitchInst case indexing with low level indexing (TI successors indexing, User's operands indexing), since it may be dangerous.
2. By the same reason findCaseValue(ConstantInt*) returns actual number of case value. 0 means first case, not default. If there is no case with given value, ErrorIndex will returned.
3. Added getCaseSuccessor method. I propose to avoid usage of TerminatorInst::getSuccessor if you want to resolve case successor BB. Use getCaseSuccessor instead, since internal SwitchInst organization of operands/successors is hidden and may be changed in any moment.
4. Added resolveSuccessorIndex and resolveCaseIndex. The main purpose of these methods is to see how case successors are really mapped in TerminatorInst.
4.1 "resolveSuccessorIndex" was created if you need to level down from SwitchInst to TerminatorInst. It returns TerminatorInst's successor index for given case successor.
4.2 "resolveCaseIndex" converts low level successors index to case index that curresponds to the given successor.
Note: There are also related compatability fix patches for dragonegg, klee, llvm-gcc-4.0, llvm-gcc-4.2, safecode, clang.
llvm-svn: 149481
This removes implicit assumption about the form of MI coming into regalloc. In particular, it should be independent of ProcessImplicitDefs which will eventually become a standard part of coming out of SSA--unless we simply can eliminate IMPLICIT_DEF completely. Current unit tests expose this once I remove incidental pass ordering restrictions.
This is not a final fix. Just a temporary workaround until I figure out the right way.
llvm-svn: 149360
vectors of all one bits to be printed more cleverly in the AsmPrinter.
Unfortunately, the byte value for all one bits is the same with
-fsigned-char as the error return of '-1'. Force this to be the unsigned
byte value when returning it to avoid this problem, and update the test
case for the shiny new behavior.
Yay for building LLVM and Clang with -funsigned-char.
Chris, please review, and let me know if there is any reason to not
desire this change. It seems good on the surface, and certainly intended
based on the code written.
llvm-svn: 149299
- Don't call malloc+free in the very hot forward().
- Don't call isTiedToDefOperand().
- Don't create BitVector temporaries.
- Merge DeadRegs into KillRegs.
- Eliminate the early clobber checks, they were irrelevant to scavenging.
- Remove unnecessary code from -Asserts builds.
This speeds up ARM PEI by 3.4x and overall llc -O0 codegen time by 11%.
llvm-svn: 149189
Sometimes there is only one 'resume' instruction per function. In those
situations, we don't need a separate block for the call to _Unwind_Resume. In
fact, it adds a lot of overhead to code-gen if we do that -- especially at -O0.
If we have a single 'resume' instruction, just generate the call within that
block.
<rdar://problem/10694814>
llvm-svn: 149159
around within a basic block while maintaining live-intervals.
Updated ScheduleTopDownLive in MachineScheduler.cpp to use the moveInstr API
when reordering MIs.
llvm-svn: 149147
GEP instructions are there for the compiler and shouldn't really output much
code (if any at all). When a GEP is stored in the entry block, Fast ISel (for
one) will not know that it could fold it into further uses. For instance, inside
of the EH handling code. This results in a lot of unnecessary spills and loads
which bloat code and slows down pretty much everything.
<rdar://problem/10694814>
llvm-svn: 149114
mid-level constant folding APIs instead of doing its own analysis.
This makes it more general (e.g. can now share a <2 x i64> with a
<4 x i32>) and avoid duplicating a bunch of logic.
llvm-svn: 149111
we're at it, allow PatternMatch's "neg" pattern to match integer
vector negations, and enhance ComputeNumSigned bits to handle
shl of vectors.
llvm-svn: 149082
MachineBasicBlock::canFallThrough(). We're interested in the state of the
instruction (i.e., is this a barrier or not?), not if the instruction is
predicable or not.
rdar://10501092
llvm-svn: 149070
The live range of the source register may be extended when a redundant
copy is eliminated. Make sure any kill flags between the two copies are
cleared.
This fixes PR11765.
llvm-svn: 149069
This enables the linker to match concrete relocation types (absolute or relative) with whatever library or C++ support code is being linked against.
llvm-svn: 149057
This boils down to using MachineOperand::readsReg() more.
This fixes PR11829 where a use ended up after the first def when
lowering REG_SEQUENCE instructions involving IMPLICIT_DEFs.
llvm-svn: 148996
function. They don't appear to be used, and are inconsistent with handling of
other physreg intervals (i.e. intervals that are not live-in) where ranges are
not inserted for aliases.
llvm-svn: 148986
A REG_SEQUENCE instruction is lowered into a sequence of partial defs:
%vreg7:ssub_0<def,undef> = COPY %vreg20:ssub_0
%vreg7:ssub_1<def> = COPY %vreg2
%vreg7:ssub_2<def> = COPY %vreg2
%vreg7:ssub_3<def> = COPY %vreg2
The first def needs an <undef> flag to indicate it is the beginning of
the live range, while the other defs are read-modify-write. Previously,
we depended on LiveIntervalAnalysis to notice and fix the missing
<def,undef>, but that solution was never robust, it was causing problems
with ProcessImplicitDefs and the lowering of chained REG_SEQUENCE
instructions.
This fixes PR11841.
llvm-svn: 148879
This change adds an new option --arm-enable-ehabi-descriptors that
enables emitting unwinding descriptors. This provides a mode with a
working backtrace() without the (currently broken) exception support.
llvm-svn: 148800
and clean up some other misc stuff. Unlike ConstantArray, we will
prefer to emit .fill directives for "String" arrays that all have
the same value, since they are denser than emitting a .ascii
llvm-svn: 148793
violation -- MC cannot depend on CodeGen.
Specifically, the MCTargetDesc component of each target is actually
a subcomponent of the MC library. As such, it cannot depend on the
target-independent code generator, because MC itself cannot depend on
the target-independent code generator. This change moved a flag from the
ARM MCTargetDesc file ARMMCAsmInfo.cpp to the CodeGen layer in
ARMException.cpp, leaving behind an 'extern' to refer back to it. That
layering order isn't viable givin the constraints outlined above.
Commandline flags are designed to be static specifically to avoid these
types of bugs.
Fixing this is likely going to require some non-trivial refactoring.
llvm-svn: 148759
This change adds an new value to the --arm-enable-ehabi option that
disables emitting unwinding descriptors. This mode gives a working
backtrace() without the (currently broken) exception support.
llvm-svn: 148686
A register mask operand kills any live physreg that isn't preserved.
Unlike an implicit-def operand, the clobbered physregs are never live
afterwards.
This means LiveVariables has to track a much smaller number of live
physregs, and it should spend much less time in addRegisterDead().
llvm-svn: 148609
Problem: LLVM needs more function attributes than currently available (32 bits).
One such proposed attribute is "address_safety", which shows that a function is being checked for address safety (by AddressSanitizer, SAFECode, etc).
Solution:
- extend the Attributes from 32 bits to 64-bits
- wrap the object into a class so that unsigned is never erroneously used instead
- change "unsigned" to "Attributes" throughout the code, including one place in clang.
- the class has no "operator uint64 ()", but it has "uint64_t Raw() " to support packing/unpacking.
- the class has "safe operator bool()" to support the common idiom: if (Attributes attr = getAttrs()) useAttrs(attr);
- The CTOR from uint64_t is marked explicit, so I had to add a few explicit CTOR calls
- Add the new attribute "address_safety". Doing it in the same commit to check that attributes beyond first 32 bits actually work.
- Some of the functions from the Attribute namespace are worth moving inside the class, but I'd prefer to have it as a separate commit.
Tested:
"make check" on Linux (32-bit and 64-bit) and Mac (10.6)
built/run spec CPU 2006 on Linux with clang -O2.
This change will break clang build in lib/CodeGen/CGCall.cpp.
The following patch will fix it.
llvm-svn: 148553
'insertvalue' instructions that recreate the structure returned by the
'landingpad' instruction. Because the 'insertvalue' instruction isn't supported
by FastISel, this can save a bit of time during -O0 compilation.
llvm-svn: 148520
to instruction right after the last instruction in the bundle.
- Add a finalizeBundle() variant that doesn't specify LastMI. Instead, the code
will find the last instruction in the bundle by following the 'InsideBundle'
marker. This is useful in case bundles are formed early (i.e. during MI
scheduling) but finalized later (i.e. after register allocator has finished
rewriting virtual registers with physical registers).
llvm-svn: 148444
This SelectionDAG node will be attached to call nodes by LowerCall(),
and eventually becomes a MO_RegisterMask MachineOperand on the
MachineInstr representing the call instruction.
LowerCall() will attach a register mask that depends on the calling
convention.
llvm-svn: 148436
(This time I believe I've checked all the -Wreturn-type warnings from GCC & added the couple of llvm_unreachables necessary to silence them. If I've missed any, I'll happily fix them as soon as I know about them)
llvm-svn: 148262
Register masks will be used as a compact representation of large clobber
lists. Currently, an x86 call instruction has some 40 operands
representing call-clobbered registers. That's more than 1kB of useless
operands per call site.
A register mask operand references a bit mask of call-preserved
registers, everything else is clobbered. The bit mask will typically
come from TargetRegisterInfo::getCallPreservedMask().
By abandoning ImplicitDefs for call-clobbered registers, it also becomes
possible to share call instruction descriptions between calling
conventions, and we can get rid of the WINCALL* instructions.
This patch introduces the new operand kind. Future patches will add
RegMask support to target-independent passes before finally the fixed
clobber lists can be removed from call instruction descriptions.
llvm-svn: 148250
We know that the blend instructions only use the MSB, so if the mask is
sign-extended then we can convert it into a SHL instruction. This is a
common pattern because the type-legalizer sign-extends the i1 type which
is used by the LLVM-IR for the condition.
Added a new optimization in SimplifyDemandedBits for SIGN_EXTEND_INREG -> SHL.
llvm-svn: 148225
live across BBs before register allocation. This miscompiled 197.parser
when a cmp + b are optimized to a cbnz instruction even though the CPSR def
is live-in a successor.
cbnz r6, LBB89_12
...
LBB89_12:
ble LBB89_1
The fix consists of two parts. 1) Teach LiveVariables that some unallocatable
registers might be liveouts so don't mark their last use as kill if they are.
2) ARM constantpool island pass shouldn't form cbz / cbnz if the conditional
branch does not kill CPSR.
rdar://10676853
llvm-svn: 148168
overly conservative. It was concerned about cases where it would prohibit
folding simple [r, c] addressing modes. e.g.
ldr r0, [r2]
ldr r1, [r2, #4]
=>
ldr r0, [r2], #4
ldr r1, [r2]
Change the logic to look for such cases which allows it to form indexed memory
ops more aggressively.
rdar://10674430
llvm-svn: 148086
The registers are placed into the saved registers list in the reverse order,
which is why the original loop was written to loop backwards.
llvm-svn: 148064
killed registers are needed below the insertion point, then unset the kill
marker.
Sorry I'm not able to find a reduced test case.
rdar://10660944
llvm-svn: 148043
When we load the v12i32 type, the GenWidenVectorLoads method generates two loads: v8i32 and v4i32
and attempts to use CONCAT_VECTORS to join them. In this fix I concat undef values to widen
the smaller value. The test "widen_load-2.ll" also exposes this bug on AVX.
llvm-svn: 147964
detect a pattern which can be implemented with a small 'shl' embedded in
the addressing mode scale. This happens in real code as follows:
unsigned x = my_accelerator_table[input >> 11];
Here we have some lookup table that we look into using the high bits of
'input'. Each entity in the table is 4-bytes, which means this
implicitly gets turned into (once lowered out of a GEP):
*(unsigned*)((char*)my_accelerator_table + ((input >> 11) << 2));
The shift right followed by a shift left is canonicalized to a smaller
shift right and masking off the low bits. That hides the shift right
which x86 has an addressing mode designed to support. We now detect
masks of this form, and produce the longer shift right followed by the
proper addressing mode. In addition to saving a (rather large)
instruction, this also reduces stalls in Intel chips on benchmarks I've
measured.
In order for all of this to work, one part of the DAG needs to be
canonicalized *still further* than it currently is. This involves
removing pointless 'trunc' nodes between a zextload and a zext. Without
that, we end up generating spurious masks and hiding the pattern.
llvm-svn: 147936
Consider this code:
int h() {
int x;
try {
x = f();
g();
} catch (...) {
return x+1;
}
return x;
}
The variable x is undefined on the first edge to the landing pad, but it
has the f() return value on the second edge to the landing pad.
SplitAnalysis::getLastSplitPoint() would assume that the return value
from f() was live into the landing pad when f() throws, which is of
course impossible.
Detect these cases, and treat them as if the landing pad wasn't there.
This allows spill code to be inserted after the function call to f().
<rdar://problem/10664933>
llvm-svn: 147912
Delete the alternative implementation in LiveIntervalAnalysis.
These functions computed the same thing, but SplitAnalysis caches the
result.
llvm-svn: 147911
of several newly un-defaulted switches. This also helps optimizers
(including LLVM's) recognize that every case is covered, and we should
assume as much.
llvm-svn: 147861
define physical registers. It's currently very restrictive, only catching
cases where the CE is in an immediate (and only) predecessor. But it catches
a surprising large number of cases.
rdar://10660865
llvm-svn: 147827
Hal Finkel