1. GlobalBaseReg may have been spilled.
2. It may not be live at the use.
3. Spiller doesn't know this is happening so it won't prevent GlobalBaseReg from being spilled later (That by itself is a nasty hack. It's needed because we don't insert the reload until later).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60595 91177308-0d34-0410-b5e6-96231b3b80d8
foldMemoryOperand how to "fold" them, by converting them into constant-pool
loads. When they aren't folded, they use xorps/cmpeqd, but for example when
register pressure is high, they may now be folded as memory operands, which
reduces register pressure.
Also, mark V_SET0 isAsCheapAsAMove so that two-address-elimination will
remat it instead of copying zeros around (V_SETALLONES was already marked).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60461 91177308-0d34-0410-b5e6-96231b3b80d8
the conditional for the BRCOND statement. For instance, it will generate:
addl %eax, %ecx
jo LOF
instead of
addl %eax, %ecx
; About 10 instructions to compare the signs of LHS, RHS, and sum.
jl LOF
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60123 91177308-0d34-0410-b5e6-96231b3b80d8
Where previously LLVM might emit code like this:
ucomisd %xmm1, %xmm0
setne %al
setp %cl
orb %al, %cl
jne .LBB4_2
it now emits this:
ucomisd %xmm1, %xmm0
jne .LBB4_2
jp .LBB4_2
It has fewer instructions and uses fewer registers, but it does
have more branches. And in the case that this code is followed by
a non-fallthrough edge, it may be followed by a jmp instruction,
resulting in three branch instructions in sequence. Some effort
is made to avoid this situation.
To achieve this, X86ISelLowering.cpp now recognizes FCMP_OEQ and
FCMP_UNE in lowered form, and replace them with code that emits
two branches, except in the case where it would require converting
a fall-through edge to an explicit branch.
Also, X86InstrInfo.cpp's branch analysis and transform code now
knows now to handle blocks with multiple conditional branches. It
uses loops instead of having fixed checks for up to two
instructions. It can now analyze and transform code generated
from FCMP_OEQ and FCMP_UNE.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57873 91177308-0d34-0410-b5e6-96231b3b80d8
the copy instruction from the instruction list before asking the
target to create the new instruction. This gets the old instruction
out of the way so that it doesn't interfere with the target's
rematerialization code. In the case of x86, this helps it find
more cases where EFLAGS is not live.
Also, in the X86InstrInfo.cpp, teach isSafeToClobberEFLAGS to check
to see if it reached the end of the block after scanning each
instruction, instead of just before. This lets it notice when the
end of the block is only two instructions away, without doing any
additional scanning.
These changes allow rematerialization to clobber EFLAGS in more
cases, for example using xor instead of mov to set the return value
to zero in the included testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57872 91177308-0d34-0410-b5e6-96231b3b80d8
shift counts, and patterns that match dynamic shift counts
when the subtract is obscured by a truncate node.
Add DAGCombiner support for recognizing rotate patterns
when the shift counts are defined by truncate nodes.
Fix and simplify the code for commuting shld and shrd
instructions to work even when the given instruction doesn't
have a parent, and when the caller needs a new instruction.
These changes allow LLVM to use the shld, shrd, rol, and ror
instructions on x86 to replace equivalent code using two
shifts and an or in many more cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57662 91177308-0d34-0410-b5e6-96231b3b80d8
and X86FastISel.cpp into X86MachineFunction.h, so that it
can be shared, instead of having each selector keep track
of its own.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56825 91177308-0d34-0410-b5e6-96231b3b80d8
isImmediate(), isRegister(), and friends, to avoid confusion
about having two different names with the same meaning. I'm
not attached to the longer names, and would be ok with
changing to the shorter names if others prefer it.
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was inserted or not. This allows bitcast in fast isel to properly handle the case
where an appropriate reg-to-reg copy is not available.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55375 91177308-0d34-0410-b5e6-96231b3b80d8
LowerSubregs, and fix an x86-64 isel bug that this exposed.
SUBREG_TO_REG for x86-64 implicit zero extension is only safe for
isel to generate when the source is known to always have zeros in
the high 32 bits. The EXTRACT_SUBREG instruction does not clear
the high 32 bits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54444 91177308-0d34-0410-b5e6-96231b3b80d8
replacement of multiple values. This is slightly more efficient
than doing multiple ReplaceAllUsesOfValueWith calls, and theoretically
could be optimized even further. However, an important property of this
new function is that it handles the case where the source value set and
destination value set overlap. This makes it feasible for isel to use
SelectNodeTo in many very common cases, which is advantageous because
SelectNodeTo avoids a temporary node and it doesn't require CSEMap
updates for users of values that don't change position.
Revamp MorphNodeTo, which is what does all the work of SelectNodeTo, to
handle operand lists more efficiently, and to correctly handle a number
of corner cases to which its new wider use exposes it.
This commit also includes a change to the encoding of post-isel opcodes
in SDNodes; now instead of being sandwiched between the target-independent
pre-isel opcodes and the target-dependent pre-isel opcodes, post-isel
opcodes are now represented as negative values. This makes it possible
to test if an opcode is pre-isel or post-isel without having to know
the size of the current target's post-isel instruction set.
These changes speed up llc overall by 3% and reduce memory usage by 10%
on the InstructionCombining.cpp testcase with -fast and -regalloc=local.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53728 91177308-0d34-0410-b5e6-96231b3b80d8
MachineMemOperands. The pools are owned by MachineFunctions.
This drastically reduces the number of calls to malloc/free made
during the "Emit" phase of scheduling, as well as later phases
in CodeGen. Combined with other changes, this speeds up the
"instruction selection" phase of CodeGen by 10% in some cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53212 91177308-0d34-0410-b5e6-96231b3b80d8
- Also remove LiveVariables::instructionChanged, etc. Replace all calls with cheaper calls which update VarInfo kill list.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53097 91177308-0d34-0410-b5e6-96231b3b80d8
Also, if LV isn't around, then TwoAddr doesn't need to be updating flags, since they won't have been set in the first place.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53058 91177308-0d34-0410-b5e6-96231b3b80d8
the need for a flavor operand, and add a new SDNode subclass,
LabelSDNode, for use with them to eliminate the need for a label id
operand.
Change instruction selection to let these label nodes through
unmodified instead of creating copies of them. Teach the MachineInstr
emitter how to emit a MachineInstr directly from an ISD label node.
This avoids the need for allocating SDNodes for the label id and
flavor value, as well as SDNodes for each of the post-isel label,
label id, and label flavor.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52943 91177308-0d34-0410-b5e6-96231b3b80d8
and better control the abstraction. Rename the type
to MVT. To update out-of-tree patches, the main
thing to do is to rename MVT::ValueType to MVT, and
rewrite expressions like MVT::getSizeInBits(VT) in
the form VT.getSizeInBits(). Use VT.getSimpleVT()
to extract a MVT::SimpleValueType for use in switch
statements (you will get an assert failure if VT is
an extended value type - these shouldn't exist after
type legalization).
This results in a small speedup of codegen and no
new testsuite failures (x86-64 linux).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52044 91177308-0d34-0410-b5e6-96231b3b80d8
This eliminates the need for several awkward casts, including
the last dynamic_cast under lib/Target.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51091 91177308-0d34-0410-b5e6-96231b3b80d8
other things, this allows the scheduler to unfold a load operand
in the 2008-01-08-SchedulerCrash.ll testcase, so it now successfully
clones the comparison to avoid a pushf+popf.
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Note: the coalescer will have to be careful about this too, when it starts coalescing insert_subreg nodes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48329 91177308-0d34-0410-b5e6-96231b3b80d8
Change insert/extract subreg instructions to be able to be used in TableGen patterns.
Use the above features to reimplement an x86-64 pseudo instruction as a pattern.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48130 91177308-0d34-0410-b5e6-96231b3b80d8
an RFP register class.
Teach ScheduleDAG how to handle CopyToReg with different src/dst
reg classes.
This allows us to compile trivial inline asms that expect stuff
on the top of x87-fp stack.
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This allows us to sink things like:
cvtsi2sd 32(%esp), %xmm1
when reading from the argument area, for example.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45895 91177308-0d34-0410-b5e6-96231b3b80d8
both work right according to the new flags.
This removes the TII::isReallySideEffectFree predicate, and adds
TII::isInvariantLoad.
It removes NeverHasSideEffects+MayHaveSideEffects and adds
UnmodeledSideEffects as machine instr flags. Now the clients
can decide everything they need.
I think isRematerializable can be implemented in terms of the
flags we have now, though I will let others tackle that.
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over to using them, instead of diddling Flags directly. Change the
various flags from const variables to enums.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45677 91177308-0d34-0410-b5e6-96231b3b80d8
that it is cheap and efficient to get.
Move a variety of predicates from TargetInstrInfo into
TargetInstrDescriptor, which makes it much easier to query a predicate
when you don't have TII around. Now you can use MI->getDesc()->isBranch()
instead of going through TII, and this is much more efficient anyway. Not
all of the predicates have been moved over yet.
Update old code that used MI->getInstrDescriptor()->Flags to use the
new predicates in many places.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45674 91177308-0d34-0410-b5e6-96231b3b80d8
