When the return value is not used (i.e. only care about the value in the memory), x86 does not have to use add to implement these. Instead, it can use add, sub, inc, dec instructions with the "lock" prefix.
This is currently implemented using a bit of instruction selection trick. The issue is the target independent pattern produces one output and a chain and we want to map it into one that just output a chain. The current trick is to select it into a merge_values with the first definition being an implicit_def. The proper solution is to add new ISD opcodes for the no-output variant. DAG combiner can then transform the node before it gets to target node selection.
Problem #2 is we are adding a whole bunch of x86 atomic instructions when in fact these instructions are identical to the non-lock versions. We need a way to add target specific information to target nodes and have this information carried over to machine instructions. Asm printer (or JIT) can use this information to add the "lock" prefix.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77582 91177308-0d34-0410-b5e6-96231b3b80d8
due to x86 encoding restrictions. This is currently off by default
because it may cause code quality regressions. This is for PR4572.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77565 91177308-0d34-0410-b5e6-96231b3b80d8
and convert code to using it, instead of having lots of things
poke the isLookupPtrRegClass() method directly.
2. Make PointerLikeRegClass contain a 'kind' int, and store it in
the existing regclass field of TargetOperandInfo when the
isLookupPtrRegClass() predicate is set. Make getRegClass pass
this into TargetRegisterInfo::getPointerRegClass(), allowing
targets to have multiple ptr_rc things.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77504 91177308-0d34-0410-b5e6-96231b3b80d8
it is highly specific to the object file that will be generated in the end,
this introduces a new TargetLoweringObjectFile interface that is implemented
for each of ELF/MachO/COFF/Alpha/PIC16 and XCore.
Though still is still a brutal and ugly refactoring, this is a major step
towards goodness.
This patch also:
1. fixes a bunch of dangling pointer problems in the PIC16 backend.
2. disables the TargetLowering copy ctor which PIC16 was accidentally using.
3. gets us closer to xcore having its own crazy target section flags and
pic16 not having to shadow sections with its own objects.
4. fixes wierdness where ELF targets would set CStringSection but not
CStringSection_. Factor the code better.
5. fixes some bugs in string lowering on ELF targets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77294 91177308-0d34-0410-b5e6-96231b3b80d8
'unnamed' bss section, but some impls would want a named one. Since
they don't have consistent behavior, just make each target do their
own thing, instead of doing something "sortof common" then having
targets change immutable objects later.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77165 91177308-0d34-0410-b5e6-96231b3b80d8
group instead of a bunch of random unrelated ideas. Provide predicates
to categorize a SectionKind into a group, and use them instead of
getKind() throughout the code.
This also renames a ton of SectionKinds to be more consistent and
evocative, and adds a huge number of comments on the enums so that
I will hopefully be able to remember how this stuff works long from
now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77129 91177308-0d34-0410-b5e6-96231b3b80d8
1. Spell SectionFlags::Writeable as "Writable".
2. Add predicates for deriving SectionFlags from SectionKinds.
3. Sink ELF-specific getSectionPrefixForUniqueGlobal impl into
ELFTargetAsmInfo.
4. Fix SectionFlagsForGlobal to know that BSS/ThreadBSS has the
BSS bit set (the real fix for PR4619).
5. Fix isSuitableForBSS to not put globals with explicit sections
set in BSS (which was the reason #4 wasn't fixed earlier).
6. Remove my previous hack for PR4619.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77085 91177308-0d34-0410-b5e6-96231b3b80d8
- Instead of requiring targets to define a JIT quality match function, we just
have them specify if they support a JIT.
- Target selection for the JIT just gets the host triple and looks for the best
target which matches the triple and has a JIT.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77060 91177308-0d34-0410-b5e6-96231b3b80d8
- Some clients which used DOUT have moved to DEBUG. We are deprecating the
"magic" DOUT behavior which avoided calling printing functions when the
statement was disabled. In addition to being unnecessary magic, it had the
downside of leaving code in -Asserts builds, and of hiding potentially
unnecessary computations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77019 91177308-0d34-0410-b5e6-96231b3b80d8
It's classifications now include elf-specific discriminators. Targets
that don't have these features (like darwin and pecoff) simply treat
data.rel like data, etc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76993 91177308-0d34-0410-b5e6-96231b3b80d8
The later doesn't depend on any crazy LLVM IR stuff, and this
pulls the concatenation of prefix with GV name (the root problem behind
PR4584) out one level.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76948 91177308-0d34-0410-b5e6-96231b3b80d8
