diff options
Diffstat (limited to 'llvm/lib/Target/PowerPC/PPCInstrInfo.h')
| -rw-r--r-- | llvm/lib/Target/PowerPC/PPCInstrInfo.h | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.h b/llvm/lib/Target/PowerPC/PPCInstrInfo.h index d98597f483406..43973c627fcf1 100644 --- a/llvm/lib/Target/PowerPC/PPCInstrInfo.h +++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.h @@ -565,14 +565,18 @@ public: int64_t OffsetImm) const; /// Fixup killed/dead flag for register \p RegNo between instructions [\p - /// StartMI, \p EndMI]. Some PostRA transformations may violate register - /// killed/dead flags semantics, this function can be called to fix up. Before - /// calling this function, + /// StartMI, \p EndMI]. Some pre-RA or post-RA transformations may violate + /// register killed/dead flags semantics, this function can be called to fix + /// up. Before calling this function, /// 1. Ensure that \p RegNo liveness is killed after instruction \p EndMI. /// 2. Ensure that there is no new definition between (\p StartMI, \p EndMI) /// and possible definition for \p RegNo is \p StartMI or \p EndMI. - /// 3. Ensure that all instructions between [\p StartMI, \p EndMI] are in same - /// basic block. + /// 3. We can do accurate fixup for the case when all instructions between + /// [\p StartMI, \p EndMI] are in same basic block. + /// 4. For the case when \p StartMI and \p EndMI are not in same basic block, + /// we conservatively clear kill flag for all uses of \p RegNo for pre-RA + /// and for post-RA, we give an assertion as without reaching definition + /// analysis post-RA, \p StartMI and \p EndMI are hard to keep right. void fixupIsDeadOrKill(MachineInstr &StartMI, MachineInstr &EndMI, unsigned RegNo) const; void replaceInstrWithLI(MachineInstr &MI, const LoadImmediateInfo &LII) const; |