1. we already know the value is dead, so don't bother replacing
it with undef.
2. The very case the comment describes actually makes the load
live which asserts in deletenode. If we do the replacement
and the node becomes live, just treat it as new. This fixes
a failure on X86/2008-01-16-InvalidDAGCombineXform.ll with
some local changes in my tree.
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dead stuff around. This gets fed into the isel pass and causes certain foldings from
happening because nodes have extraneous uses floating around. For example, if we turned
foo(bar(x)) -> baz(x), we sometimes left bar(x) around.
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precision integers. This won't actually work
(and most of the code is dead) unless the new
legalization machinery is turned on. While
there, I rationalized the handling of i1, and
removed some bogus (and unused) sextload patterns.
For i1, this could result in microscopically
better code for some architectures (not X86).
It might also result in worse code if annotating
with AssertZExt nodes turns out to be more harmful
than helpful.
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NDEBUG. This is in response to a really nasty bug I introduced that
Dale tracked down, hopefully this won't happen in the future.
Many thanks Dale.
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integers. Handle truncstore of a legal type to an unusual
number of bits. Most of this code is not reachable unless
the new legalize infrastructure is turned on.
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1. Legalize now always promotes truncstore of i1 to i8.
2. Remove patterns and gunk related to truncstore i1 from targets.
3. Rename the StoreXAction stuff to TruncStoreAction in TLI.
4. Make the TLI TruncStoreAction table a 2d table to handle from/to conversions.
5. Mark a wide variety of invalid truncstores as such in various targets, e.g.
X86 currently doesn't support truncstore of any of its integer types.
6. Add legalize support for truncstores with invalid value input types.
7. Add a dag combine transform to turn store(truncate) into truncstore when
safe.
The later allows us to compile CodeGen/X86/storetrunc-fp.ll to:
_foo:
fldt 20(%esp)
fldt 4(%esp)
faddp %st(1)
movl 36(%esp), %eax
fstps (%eax)
ret
instead of:
_foo:
subl $4, %esp
fldt 24(%esp)
fldt 8(%esp)
faddp %st(1)
fstps (%esp)
movl 40(%esp), %eax
movss (%esp), %xmm0
movss %xmm0, (%eax)
addl $4, %esp
ret
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and switch various codegen pieces and the X86 backend over
to using it.
* Add some comments to SelectionDAGNodes.h
* Introduce a second argument to FP_ROUND, which indicates
whether the FP_ROUND changes the value of its input. If
not it is safe to xform things like fp_extend(fp_round(x)) -> x.
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and the spill is its kill. However, if the local allocator has determined the
register has not been modified (possible when its value was reloaded), it would
not issue a restore. In that case, mark the last use of the virtual register as
kill.
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It's not safe to use the two value CombineTo variant to combine away a dead load.
e.g.
v1, chain2 = load chain1, loc
v2, chain3 = load chain2, loc
v3 = add v2, c
Now we replace use of v1 with undef, use of chain2 with chain1.
ReplaceAllUsesWith() will iterate through uses of the first load and update operands:
v1, chain2 = load chain1, loc
v2, chain3 = load chain1, loc
v3 = add v2, c
Now the second load is the same as the first load, SelectionDAG cse will ensure
the use of second load is replaced with the first load.
v1, chain2 = load chain1, loc
v3 = add v1, c
Then v1 is replaced with undef and bad things happen.
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into the ANY_EXTEND/ZERO_EXTEND/SIGN_EXTEND code to simplify it.
Unmerge the code for FP_ROUND and FP_EXTEND from each other to
make each one simpler.
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ShortenEHDataFor64Bits as a not-very-accurate
abstraction to cover all the changes in DwarfWriter.
Some cosmetic changes to Darwin assembly code for
gcc testsuite compatibility.
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has no stores between the load and the end of block. This works
great and sinks hundreds of stores, but we can't turn it on because
machineinstrs don't have volatility information and we don't want to
sink volatile stores :(
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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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Likewise fix up a bunch of other libcalls. While
there I remove NEG_F32 and NEG_F64 since they are
not used anywhere. This fixes 9 Ada ACATS failures.
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