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path: root/llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
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* [ARM][LowOverheadLoops] Correct offset checkingSam Parker2019-07-111-3/+13
| | | | | | | | | | | | | | | | This patch addresses a couple of problems: 1) The maximum supported offset of LE is -4094. 2) The offset of WLS also needs to be checked, this uses a maximum positive offset of 4094. The use of BasicBlockUtils has been changed because the block offsets weren't being initialised, but the isBBInRange checks both positive and negative offsets. ARMISelLowering has been tweaked because the test case presented another pattern that we weren't supporting. llvm-svn: 365749
* [NFC][ARM] Convert lambdas to static helpersSam Parker2019-07-101-57/+73
| | | | | | | Break up and convert some of the lambdas in ARMLowOverheadLoops into static functions. llvm-svn: 365623
* [ARM] WLS/LE Code GenerationSam Parker2019-07-011-27/+89
| | | | | | | | | | | | | | | | | Backend changes to enable WLS/LE low-overhead loops for armv8.1-m: 1) Use TTI to communicate to the HardwareLoop pass that we should try to generate intrinsics that guard the loop entry, as well as setting the loop trip count. 2) Lower the BRCOND that uses said intrinsic to an Arm specific node: ARMWLS. 3) ISelDAGToDAG the node to a new pseudo instruction: t2WhileLoopStart. 4) Add support in ArmLowOverheadLoops to handle the new pseudo instruction. Differential Revision: https://reviews.llvm.org/D63816 llvm-svn: 364733
* [ARM] Fix for DLS/LE CodeGenSam Parker2019-06-251-8/+9
| | | | | | | | | The expensive buildbots highlighted the mir tests were broken, which I've now updated and added --verify-machineinstrs to them. This also uncovered a couple of bugs in the backend pass, so these have also been fixed. llvm-svn: 364323
* [ARM] DLS/LE low-overhead loop code generationSam Parker2019-06-251-0/+295
Introduce three pseudo instructions to be used during DAG ISel to represent v8.1-m low-overhead loops. One maps to set_loop_iterations while loop_decrement_reg is lowered to two, so that we can separate the decrement and branching operations. The pseudo instructions are expanded pre-emission, where we can still decide whether we actually want to generate a low-overhead loop, in a new pass: ARMLowOverheadLoops. The pass currently bails, reverting to an sub, icmp and br, in the cases where a call or stack spill/restore happens between the decrement and branching instructions, or if the loop is too large. Differential Revision: https://reviews.llvm.org/D63476 llvm-svn: 364288
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