11 /// - it expands a branch or jump instruction into a long branch if its offset
18 /// Example of that is a situation where at first, no branch should be expanded,
21 /// case it is necessary to check again if there is some branch that needs
22 /// expansion. On the other hand, expanding some branch may cause a control
28 /// Regarding branch expanding:
30 /// When branch instruction like beqzc or bnezc has offset that is too large
37 /// Regarding compact branch hazard prevention:
42 /// A forbidden slot hazard occurs when a compact branch instruction is executed
44 /// such as a branch or jump, ERET, ERETNC, DERET, WAIT and PAUSE.
59 /// A) A previous pass has created a compact branch directly.
60 /// B) Transforming a delay slot branch into compact branch. This case can be
70 /// pipeline hazards such as compact branch hazard, hence the existing hazard
108 #define DEBUG_TYPE "mips-branch-expansion"
114     SkipLongBranch("skip-mips-long-branch", cl::init(false),
115                    cl::desc("MIPS: Skip branch expansion pass."), cl::Hidden);
118     ForceLongBranch("force-mips-long-branch", cl::init(false),
144     return "Mips Branch Expansion Pass";  in getPassName()
186                 "Expand out of range branch instructions and fix forbidden"
256   // Return if MBB has no branch instructions.  in splitMBB()
263   // MBB has only one branch instruction if FirstBr is not a branch  in splitMBB()
269   assert(!FirstBr->isIndirectBranch() && "Unexpected indirect branch found.");  in splitMBB()
290   // most one branch after this loop is executed.  in initMBBInfo()
307 // Compute offset of branch in number of bytes.
313   // Compute offset of a forward branch.  in computeOffset()
321   // Compute offset of a backward branch.  in computeOffset()
336 // Replace Br with a branch which has the opposite condition code and a
354       // Octeon BBIT family of branch has an immediate operand  in replaceBranch()
357         llvm_unreachable("Unexpected immediate in branch instruction");  in replaceBranch()
364       llvm_unreachable("Unexpected operand type in branch instruction");  in replaceBranch()
369     // Bundle the instruction in the delay slot to the newly created branch  in replaceBranch()
370     // and erase the original branch.  in replaceBranch()
407 // Expand branch instructions to long branches.
522         // Bundle-align the target of indirect branch JR.  in expandToLongBranch()
525       // In NaCl, modifying the sp is not allowed in branch delay slot.  in expandToLongBranch()
526       // For MIPS32R6, we can skip using a delay slot branch.  in expandToLongBranch()
575       // We assume the branch is within-function, and that offset is within  in expandToLongBranch()
682       // At this point, offset where we need to branch does not fit into  in expandToLongBranch()
683       // immediate field of the branch instruction and is not in the same  in expandToLongBranch()
686       // do branch register.  in expandToLongBranch()
723     // Change branch destination.  in expandToLongBranch()
728     // Change branch destination and reverse condition.  in expandToLongBranch()
831       // Search for MBB's branch instruction.  in handlePossibleLongBranch()
861       // Skip if this MBB doesn't have a branch or the branch has already been  in handlePossibleLongBranch()
862       // converted to a long branch.  in handlePossibleLongBranch()