We were incorrectly conflating some add variants which don't have a
cc_out operand with the mirroring sub encodings, which do. Part of the
awesome non-orthogonality legacy of thumb1. Similarly, handling of
add/sub of an immediate was sometimes incorrectly removing the cc_out
operand for add/sub register variants.
rdar://11216577
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154411 91177308-0d34-0410-b5e6-96231b3b80d8
We had special instructions for iOS because r9 is call-clobbered, but
that is represented dynamically by the register mask operands now, so
there is no need for the pseudo-instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154144 91177308-0d34-0410-b5e6-96231b3b80d8
'add r2, #-1024' should just use 'sub r2, #1024' rather than erroring out.
Thumb1 aliases for adding a negative immediate to the stack pointer,
also.
rdar://11192734
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A MOVCCr instruction can be commuted by inverting the condition. This
can help reduce register pressure and remove unnecessary copies in some
cases.
<rdar://problem/11182914>
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The CMP->CMN alias was matching for an immediate of zero when it
should only match for negative values.
rdar://11129224
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the processor keeps a return addresses stack (RAS) which stores the address
and the instruction execution state of the instruction after a function-call
type branch instruction.
Calling a "noreturn" function with normal call instructions (e.g. bl) can
corrupt RAS and causes 100% return misprediction so LLVM should use a
unconditional branch instead. i.e.
mov lr, pc
b _foo
The "mov lr, pc" is issued in order to get proper backtrace.
rdar://8979299
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I'll let the buildbots determine the compile time improvements from this
change, but 464.h264ref has 5% faster codegen at -O2.
This patch does cause some assembly changes. Branch folding can make
different decisions about calls with dead return values.
CriticalAntiDepBreaker may choose different registers because its
liveness tracking is affected. MachineCopyPropagation may sometimes
leave a dead copy behind.
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value is zero. Instead of a cmov + op, issue an conditional op instead. e.g.
cmp r9, r4
mov r4, #0
moveq r4, #1
orr lr, lr, r4
should be:
cmp r9, r4
orreq lr, lr, #1
That is, optimize (or x, (cmov 0, y, cond)) to (or.cond x, y). Similarly extend
this to xor as well as (and x, (cmov -1, y, cond)) => (and.cond x, y).
It's possible to extend this to ADD and SUB but I don't think they are common.
rdar://8659097
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The QQ and QQQQ registers are not 'real', they are pseudo-registers used
to model some vld and vst instructions.
This makes the call clobber lists longer, but I intend to get rid of
those soon.
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When 'cmp rn #imm' doesn't match due to the immediate not being representable,
but 'cmn rn, #-imm' does match, use the latter in place of the former, as
it's equivalent.
rdar://10552389
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When the immediate operand of an AND or BIC instruction isn't representable
in the immediate field of the instruction, but the bitwise negation of the
immediate is, assemble the instruction as the inverse operation instead
with the inverted immediate as the operand.
rdar://10550057
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These immediate operands all use the same simple logic for rendering to
MCInst, so have them share the method for doing so.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144439 91177308-0d34-0410-b5e6-96231b3b80d8
When '~imm' is encodable as a t2_so_imm but plain 'imm' is not. For example,
mov r2, #-3
becomes
mvn r2, #2
rdar://10349224
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Outside an IT block, "add r3, #2" should select a 32-bit wide encoding
rather than generating an error indicating the 16-bit encoding is only
legal in an IT block (outside, the 'S' suffic is required for the 16-bit
encoding).
rdar://10348481
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We were parsing label references to the i12 encoding, which isn't right.
They need to go to the pci variant instead.
More of rdar://10348687
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Clean up the patterns, fix comments, and avoid confusing both tools
and coders. Note that the special adds/subs SelectionDAG nodes no
longer have the dummy cc_out operand.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142397 91177308-0d34-0410-b5e6-96231b3b80d8
Use the custom inserter for the ARM setjmp intrinsics. Instead of creating the
SjLj dispatch table in IR, where it frequently violates serveral assumptions --
in particular assumptions made by the landingpad instruction about what can
branch to a landing pad and what cannot. Performing this in the back-end allows
us to violate these assumptions without the IR getting angry at us.
It also allows us to perform a small optimization. We can shove the address of
the dispatch's basic block into the function context and not have to add code
around the setjmp to check for the return value and jump to the dispatch.
Neat, huh?
<rdar://problem/10116753>
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