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path: root/lib/CodeGen/AtomicExpandLoadLinkedPass.cpp
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* Add a new subtarget hook for whether or not we'd like to enableEric Christopher2014-06-19
| | | | | | | | | the atomic load linked expander pass to run for a particular subtarget. This requires a check of the subtarget and so save the TargetMachine rather than only TargetLoweringInfo and update all callers. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211314 91177308-0d34-0410-b5e6-96231b3b80d8
* Atomics: make use of the "cmpxchg weak" instruction.Tim Northover2014-06-13
| | | | | | | | | This also simplifies the IR we create slightly: instead of working out where success & failure should go manually, it turns out we can just always jump to a success/failure block created for the purpose. Later phases will sort out the mess without much difficulty. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210917 91177308-0d34-0410-b5e6-96231b3b80d8
* Atomics: switch direction of cmpxchg comparisonTim Northover2014-06-13
| | | | | | | | This has two benefits: it makes the result more suitable for direct insertaion into the struct to emulate the new cmpxchg, and it means the name we give the instruction matches its actual effect better. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210916 91177308-0d34-0410-b5e6-96231b3b80d8
* IR: add "cmpxchg weak" variant to support permitted failure.Tim Northover2014-06-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds a weak variant of the cmpxchg operation, as described in C++11. A cmpxchg instruction with this modifier is permitted to fail to store, even if the comparison indicated it should. As a result, cmpxchg instructions must return a flag indicating success in addition to their original iN value loaded. Thus, for uniformity *all* cmpxchg instructions now return "{ iN, i1 }". The second flag is 1 when the store succeeded. At the DAG level, a new ATOMIC_CMP_SWAP_WITH_SUCCESS node has been added as the natural representation for the new cmpxchg instructions. It is a strong cmpxchg. By default this gets Expanded to the existing ATOMIC_CMP_SWAP during Legalization, so existing backends should see no change in behaviour. If they wish to deal with the enhanced node instead, they can call setOperationAction on it. Beware: as a node with 2 results, it cannot be selected from TableGen. Currently, no use is made of the extra information provided in this patch. Test updates are almost entirely adapting the input IR to the new scheme. Summary for out of tree users: ------------------------------ + Legacy Bitcode files are upgraded during read. + Legacy assembly IR files will be invalid. + Front-ends must adapt to different type for "cmpxchg". + Backends should be unaffected by default. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210903 91177308-0d34-0410-b5e6-96231b3b80d8
* Create macro INITIALIZE_TM_PASS.Jiangning Liu2014-06-11
| | | | | | | | | Pass initialization requires to initialize TargetMachine for back-end specific passes. This commit creates a new macro INITIALIZE_TM_PASS to simplify this kind of initialization. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210641 91177308-0d34-0410-b5e6-96231b3b80d8
* [C++11] Use 'nullptr'.Craig Topper2014-06-08
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210442 91177308-0d34-0410-b5e6-96231b3b80d8
* ARM & AArch64: make use of common cmpxchg idioms after expansionTim Northover2014-05-30
| | | | | | | | | | | | | | | | | | | | | | | | The C and C++ semantics for compare_exchange require it to return a bool indicating success. This gets mapped to LLVM IR which follows each cmpxchg with an icmp of the value loaded against the desired value. When lowered to ldxr/stxr loops, this extra comparison is redundant: its results are implicit in the control-flow of the function. This commit makes two changes: it replaces that icmp with appropriate PHI nodes, and then makes sure earlyCSE is called after expansion to actually make use of the opportunities revealed. I've also added -{arm,aarch64}-enable-atomic-tidy options, so that existing fragile tests aren't perturbed too much by the change. Many of them either rely on undef/unreachable too pervasively to be restored to something well-defined (particularly while making sure they test the same obscure assert from many years ago), or depend on a particular CFG shape, which is disrupted by SimplifyCFG. rdar://problem/16227836 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209883 91177308-0d34-0410-b5e6-96231b3b80d8
* [C++] Use 'nullptr'.Craig Topper2014-04-24
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207083 91177308-0d34-0410-b5e6-96231b3b80d8
* [Modules] Remove potential ODR violations by sinking the DEBUG_TYPEChandler Carruth2014-04-22
| | | | | | | | | | | | define below all header includes in the lib/CodeGen/... tree. While the current modules implementation doesn't check for this kind of ODR violation yet, it is likely to grow support for it in the future. It also removes one layer of macro pollution across all the included headers. Other sub-trees will follow. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206837 91177308-0d34-0410-b5e6-96231b3b80d8
* Atomics: promote ARM's IR-based atomics pass to CodeGen.Tim Northover2014-04-17
Still only 32-bit ARM using it at this stage, but the promotion allows direct testing via opt and is a reasonably self-contained patch on the way to switching ARM64. At this point, other targets should be able to make use of it without too much difficulty if they want. (See ARM64 commit coming soon for an example). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206485 91177308-0d34-0410-b5e6-96231b3b80d8