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* [SystemZ] Use RNSBGRichard Sandiford2013-07-181-5/+0
| | | | | | | This should be the last of the R.SBG patches for now. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186573 91177308-0d34-0410-b5e6-96231b3b80d8
* [SystemZ] Immediate compare-and-branch supportRichard Sandiford2013-05-291-4/+0
| | | | | | | This patch adds support for the CIJ and CGIJ instructions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182846 91177308-0d34-0410-b5e6-96231b3b80d8
* [SystemZ] Rename PSW to CCRichard Sandiford2013-05-221-6/+0
| | | | | | | | | | | Addresses a review comment from Ulrich Weigand. No functional change intended. I'm not sure whether the old TODO that this patch touches still holds, but that's something we'd get to when adding a targetted scheduling description. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182474 91177308-0d34-0410-b5e6-96231b3b80d8
* [SystemZ] Add long branch passRichard Sandiford2013-05-201-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before this change, the SystemZ backend would use BRCL for all branches and only consider shortening them to BRC when generating an object file. E.g. a branch on equal would use the JGE alias of BRCL in assembly output, but might be shortened to the JE alias of BRC in ELF output. This was a useful first step, but it had two problems: (1) The z assembler isn't traditionally supposed to perform branch shortening or branch relaxation. We followed this rule by not relaxing branches in assembler input, but that meant that generating assembly code and then assembling it would not produce the same result as going directly to object code; the former would give long branches everywhere, whereas the latter would use short branches where possible. (2) Other useful branches, like COMPARE AND BRANCH, do not have long forms. We would need to do something else before supporting them. (Although COMPARE AND BRANCH does not change the condition codes, the plan is to model COMPARE AND BRANCH as a CC-clobbering instruction during codegen, so that we can safely lower it to a separate compare and long branch where necessary. This is not a valid transformation for the assembler proper to make.) This patch therefore moves branch relaxation to a pre-emit pass. For now, calls are still shortened from BRASL to BRAS by the assembler, although this too is not really the traditional behaviour. The first test takes about 1.5s to run, and there are likely to be more tests in this vein once further branch types are added. The feeling on IRC was that 1.5s is a bit much for a single test, so I've restricted it to SystemZ hosts for now. The patch exposes (and fixes) some typos in the main CodeGen/SystemZ tests. A later patch will remove the {{g}}s from that directory. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182274 91177308-0d34-0410-b5e6-96231b3b80d8
* [SystemZ] Add more future work items to the READMERichard Sandiford2013-05-151-7/+91
| | | | | | | Based on an analysis by Ulrich Weigand. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181882 91177308-0d34-0410-b5e6-96231b3b80d8
* [SystemZ] Add back endUlrich Weigand2013-05-061-0/+146
This adds the actual lib/Target/SystemZ target files necessary to implement the SystemZ target. Note that at this point, the target cannot yet be built since the configure bits are missing. Those will be provided shortly by a follow-on patch. This version of the patch incorporates feedback from reviews by Chris Lattner and Anton Korobeynikov. Thanks to all reviewers! Patch by Richard Sandiford. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181203 91177308-0d34-0410-b5e6-96231b3b80d8