/*****************************************************************************/ /* */ /* coptjmp.c */ /* */ /* Low level optimizations regarding branches and jumps */ /* */ /* */ /* */ /* (C) 2001-2009, Ullrich von Bassewitz */ /* Roemerstrasse 52 */ /* D-70794 Filderstadt */ /* EMail: uz@cc65.org */ /* */ /* */ /* This software is provided 'as-is', without any expressed or implied */ /* warranty. In no event will the authors be held liable for any damages */ /* arising from the use of this software. */ /* */ /* Permission is granted to anyone to use this software for any purpose, */ /* including commercial applications, and to alter it and redistribute it */ /* freely, subject to the following restrictions: */ /* */ /* 1. The origin of this software must not be misrepresented; you must not */ /* claim that you wrote the original software. If you use this software */ /* in a product, an acknowledgment in the product documentation would be */ /* appreciated but is not required. */ /* 2. Altered source versions must be plainly marked as such, and must not */ /* be misrepresented as being the original software. */ /* 3. This notice may not be removed or altered from any source */ /* distribution. */ /* */ /*****************************************************************************/ /* common */ #include "cpu.h" /* cc65 */ #include "codeent.h" #include "coptjmp.h" #include "codeinfo.h" #include "codeopt.h" #include "error.h" /*****************************************************************************/ /* Helper functions */ /*****************************************************************************/ static int GetBranchDist (CodeSeg* S, unsigned From, CodeEntry* To) /* Get the branch distance between the two entries and return it. The distance ** will be negative for backward jumps and positive for forward jumps. */ { /* Get the index of the branch target */ unsigned TI = CS_GetEntryIndex (S, To); /* Determine the branch distance */ int Distance = 0; if (TI >= From) { /* Forward branch, do not count the current insn */ unsigned J = From+1; while (J < TI) { CodeEntry* N = CS_GetEntry (S, J++); Distance += N->Size; } } else { /* Backward branch */ unsigned J = TI; while (J < From) { CodeEntry* N = CS_GetEntry (S, J++); Distance -= N->Size; } } /* Return the calculated distance */ return Distance; } static int IsShortDist (int Distance) /* Return true if the given distance is a short branch distance */ { return (Distance >= -125 && Distance <= 125); } static short ZPRegVal (unsigned short Use, const RegContents* RC) /* Return the contents of the given zeropage register */ { if ((Use & REG_TMP1) != 0) { return RC->Tmp1; } else if ((Use & REG_PTR1_LO) != 0) { return RC->Ptr1Lo; } else if ((Use & REG_PTR1_HI) != 0) { return RC->Ptr1Hi; } else if ((Use & REG_SREG_LO) != 0) { return RC->SRegLo; } else if ((Use & REG_SREG_HI) != 0) { return RC->SRegHi; } else { return UNKNOWN_REGVAL; } } static short RegVal (unsigned short Use, const RegContents* RC) /* Return the contents of the given register */ { if ((Use & REG_A) != 0) { return RC->RegA; } else if ((Use & REG_X) != 0) { return RC->RegX; } else if ((Use & REG_Y) != 0) { return RC->RegY; } else { return ZPRegVal (Use, RC); } } /*****************************************************************************/ /* Optimize branch types */ /*****************************************************************************/ unsigned OptBranchDist (CodeSeg* S) /* Change branches for the distance needed. */ { unsigned Changes = 0; /* Walk over the entries */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { /* Get next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if it's a conditional branch to a local label. */ if (E->Info & OF_CBRA) { /* Is this a branch to a local symbol? */ if (E->JumpTo != 0) { /* Check if the branch distance is short */ int IsShort = IsShortDist (GetBranchDist (S, I, E->JumpTo->Owner)); /* Make the branch short/long according to distance */ if ((E->Info & OF_LBRA) == 0 && !IsShort) { /* Short branch but long distance */ CE_ReplaceOPC (E, MakeLongBranch (E->OPC)); ++Changes; } else if ((E->Info & OF_LBRA) != 0 && IsShort) { /* Long branch but short distance */ CE_ReplaceOPC (E, MakeShortBranch (E->OPC)); ++Changes; } } else if ((E->Info & OF_LBRA) == 0) { /* Short branch to external symbol - make it long */ CE_ReplaceOPC (E, MakeLongBranch (E->OPC)); ++Changes; } } else if ((CPUIsets[CPU] & (CPU_ISET_65SC02 |CPU_ISET_6502DTV)) != 0 && (E->Info & OF_UBRA) != 0 && E->JumpTo != 0 && IsShortDist (GetBranchDist (S, I, E->JumpTo->Owner))) { /* The jump is short and may be replaced by a BRA on the 65C02 CPU */ CE_ReplaceOPC (E, OP65_BRA); ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } unsigned OptBranchDist2 (CodeSeg* S) /* Change BRA to JMP if target is an external symbol */ { unsigned Changes = 0; /* Walk over the entries */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { /* Get next entry */ CodeEntry* E = CS_GetEntry (S, I); if ((CPUIsets[CPU] & (CPU_ISET_65SC02 |CPU_ISET_6502DTV)) != 0 && /* CPU has BRA */ (E->Info & OF_UBRA) != 0 && /* is a unconditional branch */ E->JumpTo == NULL) { /* target is extern */ /* BRA jumps to external symbol and must be replaced by a JMP on the 65C02 CPU */ CE_ReplaceOPC (E, OP65_JMP); ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } /*****************************************************************************/ /* Replace jumps to RTS by RTS */ /*****************************************************************************/ unsigned OptRTSJumps1 (CodeSeg* S) /* Replace jumps to RTS by RTS */ { unsigned Changes = 0; /* Walk over all entries minus the last one */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { /* Get the next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if it's an unconditional branch to a local target */ if ((E->Info & OF_UBRA) != 0 && E->JumpTo != 0 && E->JumpTo->Owner->OPC == OP65_RTS) { /* Insert an RTS instruction */ CodeEntry* X = NewCodeEntry (OP65_RTS, AM65_IMP, 0, 0, E->LI); CS_InsertEntry (S, X, I+1); /* Delete the jump */ CS_DelEntry (S, I); /* Remember, we had changes */ ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } unsigned OptRTSJumps2 (CodeSeg* S) /* Replace long conditional jumps to RTS or to a final target */ { unsigned Changes = 0; /* Walk over all entries minus the last one */ unsigned I = 0; while (I < CS_GetEntryCount (S) - 1) { /* Get the next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if it's an conditional branch to a local target */ if ((E->Info & OF_CBRA) != 0 && /* Conditional branch */ (E->Info & OF_LBRA) != 0 && /* Long branch */ E->JumpTo != 0) { /* Local label */ /* Get the jump target and the next entry. There's always a next ** entry, because we don't cover the last entry in the loop. */ CodeEntry* X = 0; CodeEntry* T = E->JumpTo->Owner; CodeEntry* N = CS_GetNextEntry (S, I); /* Check if it's a jump to an RTS insn */ if (T->OPC == OP65_RTS) { /* It's a jump to RTS. Create a conditional branch around an ** RTS insn. */ X = NewCodeEntry (OP65_RTS, AM65_IMP, 0, 0, T->LI); } else if (T->OPC == OP65_JMP && T->JumpTo == 0) { /* It's a jump to a label outside the function. Create a ** conditional branch around a jump to the external label. */ X = NewCodeEntry (OP65_JMP, AM65_ABS, T->Arg, T->JumpTo, T->LI); } /* If we have a replacement insn, insert it */ if (X) { CodeLabel* LN; opc_t NewBranch; /* Insert the new insn */ CS_InsertEntry (S, X, I+1); /* Create a conditional branch with the inverse condition ** around the replacement insn */ /* Get the new branch opcode */ NewBranch = MakeShortBranch (GetInverseBranch (E->OPC)); /* Get the label attached to N, create a new one if needed */ LN = CS_GenLabel (S, N); /* Generate the branch */ X = NewCodeEntry (NewBranch, AM65_BRA, LN->Name, LN, E->LI); CS_InsertEntry (S, X, I+1); /* Delete the long branch */ CS_DelEntry (S, I); /* Remember, we had changes */ ++Changes; } } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } /*****************************************************************************/ /* Remove dead jumps */ /*****************************************************************************/ unsigned OptDeadJumps (CodeSeg* S) /* Remove dead jumps (jumps to the next instruction) */ { unsigned Changes = 0; /* Walk over all entries minus the last one */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { /* Get the next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if it's a branch, if it has a local target, and if the target ** is the next instruction. */ if (E->AM == AM65_BRA && E->JumpTo && E->JumpTo->Owner == CS_GetNextEntry (S, I)) { /* Delete the dead jump */ CS_DelEntry (S, I); /* Remember, we had changes */ ++Changes; } else { /* Next entry */ ++I; } } /* Return the number of changes made */ return Changes; } /*****************************************************************************/ /* Remove dead code */ /*****************************************************************************/ unsigned OptDeadCode (CodeSeg* S) /* Remove dead code (code that follows an unconditional jump or an rts/rti ** and has no label) */ { unsigned Changes = 0; /* Walk over all entries */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { CodeEntry* N; CodeLabel* LN; /* Get this entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if it's an unconditional branch, and if the next entry has ** no labels attached, or if the label is just used so that the insn ** can jump to itself. */ if ((E->Info & OF_DEAD) != 0 && /* Dead code follows */ (N = CS_GetNextEntry (S, I)) != 0 && /* Has next entry */ (!CE_HasLabel (N) || /* Don't has a label */ ((N->Info & OF_UBRA) != 0 && /* Uncond branch */ (LN = N->JumpTo) != 0 && /* Jumps to known label */ LN->Owner == N && /* Attached to insn */ CL_GetRefCount (LN) == 1))) { /* Only reference */ /* Delete the next entry */ CS_DelEntry (S, I+1); /* Remember, we had changes */ ++Changes; } else { /* Next entry */ ++I; } } /* Return the number of changes made */ return Changes; } /*****************************************************************************/ /* Optimize jump cascades */ /*****************************************************************************/ unsigned OptJumpCascades (CodeSeg* S) /* Optimize jump cascades (jumps to jumps). In such a case, the jump is ** replaced by a jump to the final location. This will in some cases produce ** worse code, because some jump targets are no longer reachable by short ** branches, but this is quite rare, so there are more advantages than ** disadvantages. */ { unsigned Changes = 0; /* Walk over all entries */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { CodeEntry* N; CodeLabel* OldLabel; /* Get this entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check: ** - if it's a branch, ** - if it has a jump label, ** - if this jump label is not attached to the instruction itself, ** - if the target instruction is itself a branch, ** - if either the first branch is unconditional or the target of ** the second branch is internal to the function. ** The latter condition will avoid conditional branches to targets ** outside of the function (usually incspx), which won't simplify the ** code, since conditional far branches are emulated by a short branch ** around a jump. */ if ((E->Info & OF_BRA) != 0 && (OldLabel = E->JumpTo) != 0 && (N = OldLabel->Owner) != E && (N->Info & OF_BRA) != 0 && ((E->Info & OF_CBRA) == 0 || N->JumpTo != 0)) { /* Check if we can use the final target label. That is the case, ** if the target branch is an absolute branch; or, if it is a ** conditional branch checking the same condition as the first one. */ if ((N->Info & OF_UBRA) != 0 || ((E->Info & OF_CBRA) != 0 && GetBranchCond (E->OPC) == GetBranchCond (N->OPC))) { /* This is a jump cascade and we may jump to the final target, ** provided that the other insn does not jump to itself. If ** this is the case, we can also jump to ourselves, otherwise ** insert a jump to the new instruction and remove the old one. */ CodeEntry* X; CodeLabel* LN = N->JumpTo; if (LN != 0 && LN->Owner == N) { /* We found a jump to a jump to itself. Replace our jump ** by a jump to itself. */ CodeLabel* LE = CS_GenLabel (S, E); X = NewCodeEntry (E->OPC, E->AM, LE->Name, LE, E->LI); } else { /* Jump to the final jump target */ X = NewCodeEntry (E->OPC, E->AM, N->Arg, N->JumpTo, E->LI); } /* Insert it behind E */ CS_InsertEntry (S, X, I+1); /* Remove E */ CS_DelEntry (S, I); /* Remember, we had changes */ ++Changes; /* Check if both are conditional branches, and the condition of ** the second is the inverse of that of the first. In this case, ** the second branch will never be taken, and we may jump directly ** to the instruction behind this one. */ } else if ((E->Info & OF_CBRA) != 0 && (N->Info & OF_CBRA) != 0) { CodeEntry* X; /* Instruction behind N */ CodeLabel* LX; /* Label attached to X */ /* Get the branch conditions of both branches */ bc_t BC1 = GetBranchCond (E->OPC); bc_t BC2 = GetBranchCond (N->OPC); /* Check the branch conditions */ if (BC1 != GetInverseCond (BC2)) { /* Condition not met */ goto NextEntry; } /* We may jump behind this conditional branch. Get the ** pointer to the next instruction */ if ((X = CS_GetNextEntry (S, CS_GetEntryIndex (S, N))) == 0) { /* N is the last entry, bail out */ goto NextEntry; } /* Get the label attached to X, create a new one if needed */ LX = CS_GenLabel (S, X); /* Move the reference from E to the new label */ CS_MoveLabelRef (S, E, LX); /* Remember, we had changes */ ++Changes; } } NextEntry: /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } /*****************************************************************************/ /* Optimize jsr/rts */ /*****************************************************************************/ unsigned OptRTS (CodeSeg* S) /* Optimize subroutine calls followed by an RTS. The subroutine call will get ** replaced by a jump. Don't bother to delete the RTS if it does not have a ** label, the dead code elimination should take care of it. */ { unsigned Changes = 0; /* Walk over all entries minus the last one */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { CodeEntry* N; /* Get this entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if it's a subroutine call and if the following insn is RTS */ if (E->OPC == OP65_JSR && (N = CS_GetNextEntry (S, I)) != 0 && N->OPC == OP65_RTS) { /* Change the jsr to a jmp and use the additional info for a jump */ E->AM = AM65_BRA; CE_ReplaceOPC (E, OP65_JMP); /* Remember, we had changes */ ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } /*****************************************************************************/ /* Optimize jump targets */ /*****************************************************************************/ unsigned OptJumpTarget1 (CodeSeg* S) /* If the instruction preceeding an unconditional branch is the same as the ** instruction preceeding the jump target, the jump target may be moved ** one entry back. This is a size optimization, since the instruction before ** the branch gets removed. */ { unsigned Changes = 0; CodeEntry* E1; /* Entry 1 */ CodeEntry* E2; /* Entry 2 */ CodeEntry* T1; /* Jump target entry 1 */ CodeLabel* TL1; /* Target label 1 */ /* Walk over the entries */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { /* Get next entry */ E2 = CS_GetNextEntry (S, I); /* Check if we have a jump or branch without a label attached, and ** a jump target, which is not attached to the jump itself */ if (E2 != 0 && (E2->Info & OF_UBRA) != 0 && !CE_HasLabel (E2) && E2->JumpTo && E2->JumpTo->Owner != E2) { /* Get the entry preceeding the branch target */ T1 = CS_GetPrevEntry (S, CS_GetEntryIndex (S, E2->JumpTo->Owner)); if (T1 == 0) { /* There is no such entry */ goto NextEntry; } /* The entry preceeding the branch target may not be the branch ** insn. */ if (T1 == E2) { goto NextEntry; } /* Get the entry preceeding the jump */ E1 = CS_GetEntry (S, I); /* Check if both preceeding instructions are identical */ if (!CodeEntriesAreEqual (E1, T1)) { /* Not equal, try next */ goto NextEntry; } /* Get the label for the instruction preceeding the jump target. ** This routine will create a new label if the instruction does ** not already have one. */ TL1 = CS_GenLabel (S, T1); /* Change the jump target to point to this new label */ CS_MoveLabelRef (S, E2, TL1); /* If the instruction preceeding the jump has labels attached, ** move references to this label to the new label. */ if (CE_HasLabel (E1)) { CS_MoveLabels (S, E1, T1); } /* Remove the entry preceeding the jump */ CS_DelEntry (S, I); /* Remember, we had changes */ ++Changes; } else { NextEntry: /* Next entry */ ++I; } } /* Return the number of changes made */ return Changes; } unsigned OptJumpTarget2 (CodeSeg* S) /* If a bcs jumps to a sec insn or a bcc jumps to clc, skip this insn, since ** it's job is already done. */ { unsigned Changes = 0; /* Walk over the entries */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { /* OP that may be skipped */ opc_t OPC; /* Jump target insn, old and new */ CodeEntry* T; CodeEntry* N; /* New jump label */ CodeLabel* L; /* Get next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if this is a bcc insn */ if (E->OPC == OP65_BCC || E->OPC == OP65_JCC) { OPC = OP65_CLC; } else if (E->OPC == OP65_BCS || E->OPC == OP65_JCS) { OPC = OP65_SEC; } else { /* Not what we're looking for */ goto NextEntry; } /* Must have a jump target */ if (E->JumpTo == 0) { goto NextEntry; } /* Get the owner insn of the jump target and check if it's the one, we ** will skip if present. */ T = E->JumpTo->Owner; if (T->OPC != OPC) { goto NextEntry; } /* Get the entry following the branch target */ N = CS_GetNextEntry (S, CS_GetEntryIndex (S, T)); if (N == 0) { /* There is no such entry */ goto NextEntry; } /* Get the label for the instruction following the jump target. ** This routine will create a new label if the instruction does ** not already have one. */ L = CS_GenLabel (S, N); /* Change the jump target to point to this new label */ CS_MoveLabelRef (S, E, L); /* Remember that we had changes */ ++Changes; NextEntry: /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } unsigned OptJumpTarget3 (CodeSeg* S) /* Jumps to load instructions of a register, that do already have the matching ** register contents may skip the load instruction, since it's job is already ** done. */ { unsigned Changes = 0; unsigned I; /* Walk over the entries */ I = 0; while (I < CS_GetEntryCount (S)) { CodeEntry* N; /* Get next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if this is a load insn with a label and the next insn is not ** a conditional branch that needs the flags from the load. */ if ((E->Info & OF_LOAD) != 0 && CE_IsConstImm (E) && CE_HasLabel (E) && (N = CS_GetNextEntry (S, I)) != 0 && !CE_UseLoadFlags (N)) { unsigned J; int K; /* New jump label */ CodeLabel* LN = 0; /* Walk over all insn that jump here */ for (J = 0; J < CE_GetLabelCount (E); ++J) { /* Get the label */ CodeLabel* L = CE_GetLabel (E, J); /* Loop over all insn that reference this label. Since we may ** eventually remove a reference in the loop, we must loop ** from end down to start. */ for (K = CL_GetRefCount (L) - 1; K >= 0; --K) { /* Get the entry that jumps here */ CodeEntry* Jump = CL_GetRef (L, K); /* Get the register info from this insn */ short Val = RegVal (E->Chg, &Jump->RI->Out2); /* Check if the outgoing value is the one thats's loaded */ if (Val == (unsigned char) E->Num) { /* OK, skip the insn. First, generate a label for the ** next insn after E. */ if (LN == 0) { LN = CS_GenLabel (S, N); } /* Change the jump target to point to this new label */ CS_MoveLabelRef (S, Jump, LN); /* Remember that we had changes */ ++Changes; } } } } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } /*****************************************************************************/ /* Optimize conditional branches */ /*****************************************************************************/ unsigned OptCondBranches1 (CodeSeg* S) /* Performs several optimization steps: ** ** - If an immediate load of a register is followed by a conditional jump that ** is never taken because the load of the register sets the flags in such a ** manner, remove the conditional branch. ** - If the conditional branch is always taken because of the register load, ** replace it by a jmp. ** - If a conditional branch jumps around an unconditional branch, remove the ** conditional branch and make the jump a conditional branch with the ** inverse condition of the first one. */ { unsigned Changes = 0; /* Walk over the entries */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { CodeEntry* N; CodeLabel* L; /* Get next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if it's a register load */ if ((E->Info & OF_LOAD) != 0 && /* It's a load instruction */ E->AM == AM65_IMM && /* ..with immidiate addressing */ CE_HasNumArg (E) && /* ..and a numeric argument. */ (N = CS_GetNextEntry (S, I)) != 0 && /* There is a following entry */ (N->Info & OF_CBRA) != 0 && /* ..which is a conditional branch */ !CE_HasLabel (N)) { /* ..and does not have a label */ /* Get the branch condition */ bc_t BC = GetBranchCond (N->OPC); /* Check the argument against the branch condition */ if ((BC == BC_EQ && E->Num != 0) || (BC == BC_NE && E->Num == 0) || (BC == BC_PL && (E->Num & 0x80) != 0) || (BC == BC_MI && (E->Num & 0x80) == 0)) { /* Remove the conditional branch */ CS_DelEntry (S, I+1); /* Remember, we had changes */ ++Changes; } else if ((BC == BC_EQ && E->Num == 0) || (BC == BC_NE && E->Num != 0) || (BC == BC_PL && (E->Num & 0x80) == 0) || (BC == BC_MI && (E->Num & 0x80) != 0)) { /* The branch is always taken, replace it by a jump */ CE_ReplaceOPC (N, OP65_JMP); /* Remember, we had changes */ ++Changes; } } if ((E->Info & OF_CBRA) != 0 && /* It's a conditional branch */ (L = E->JumpTo) != 0 && /* ..referencing a local label */ (N = CS_GetNextEntry (S, I)) != 0 && /* There is a following entry */ (N->Info & OF_UBRA) != 0 && /* ..which is an uncond branch, */ !CE_HasLabel (N) && /* ..has no label attached */ L->Owner == CS_GetNextEntry (S, I+1)) { /* ..and jump target follows */ /* Replace the jump by a conditional branch with the inverse branch ** condition than the branch around it. */ CE_ReplaceOPC (N, GetInverseBranch (E->OPC)); /* Remove the conditional branch */ CS_DelEntry (S, I); /* Remember, we had changes */ ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } unsigned OptCondBranches2 (CodeSeg* S) /* If on entry to a "rol a" instruction the accu is zero, and a beq/bne follows, ** we can remove the rol and branch on the state of the carry flag. */ { unsigned Changes = 0; unsigned I; /* Walk over the entries */ I = 0; while (I < CS_GetEntryCount (S)) { CodeEntry* N; /* Get next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Check if it's a rol insn with A in accu and a branch follows */ if (E->OPC == OP65_ROL && E->AM == AM65_ACC && E->RI->In.RegA == 0 && !CE_HasLabel (E) && (N = CS_GetNextEntry (S, I)) != 0 && (N->Info & OF_ZBRA) != 0 && !RegAUsed (S, I+1)) { /* Replace the branch condition */ switch (GetBranchCond (N->OPC)) { case BC_EQ: CE_ReplaceOPC (N, OP65_JCC); break; case BC_NE: CE_ReplaceOPC (N, OP65_JCS); break; default: Internal ("Unknown branch condition in OptCondBranches2"); } /* Delete the rol insn */ CS_DelEntry (S, I); /* Remember, we had changes */ ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; }