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SplitBlockBeforeInstr() insert a unconditional branch to the next BB. This

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is unnecessary when we are fixing up a conditional branch since we will be
adding a unconditional branch to the destination of the original branch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33517 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2007-01-26 02:02:39 +00:00
parent 129ccd9def
commit dd353b8ad7
1 changed files with 6 additions and 2 deletions
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8
lib/Target/ARM/ARMConstantIslandPass.cpp
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@ -602,13 +602,17 @@ ARMConstantIslands::FixUpImmediateBranch(MachineFunction &Fn, ImmBranch &Br) {
// direct the updated conditional branch to the fall-through block. Otherwise, // direct the updated conditional branch to the fall-through block. Otherwise,
// split the MBB before the next instruction. // split the MBB before the next instruction.
MachineBasicBlock *MBB = MI->getParent(); MachineBasicBlock *MBB = MI->getParent();
if (&MBB->back() != MI || !BBHasFallthrough(MBB)) if (&MBB->back() != MI || !BBHasFallthrough(MBB)) {
SplitBlockBeforeInstr(MI); SplitBlockBeforeInstr(MI);
// No need for the branch to the next block. We're adding a unconditional
// branch to the destination.
MBB->back().eraseFromParent();
}
MachineBasicBlock *NextBB = next(MachineFunction::iterator(MBB)); MachineBasicBlock *NextBB = next(MachineFunction::iterator(MBB));
// Insert a unconditional branch and replace the conditional branch. // Insert a unconditional branch and replace the conditional branch.
// Also update the ImmBranch as well as adding a new entry for the new branch. // Also update the ImmBranch as well as adding a new entry for the new branch.
BuildMI(MBB, TII->get(MI->getOpcode())).addMBB(NextBB).addImm((unsigned)CC); BuildMI(MBB, TII->get(MI->getOpcode())).addMBB(NextBB).addImm(CC);
Br.MI = &MBB->back(); Br.MI = &MBB->back();
BuildMI(MBB, TII->get(Br.UncondBr)).addMBB(DestBB); BuildMI(MBB, TII->get(Br.UncondBr)).addMBB(DestBB);
unsigned MaxDisp = (Br.UncondBr == ARM::tB) ? (1<<10)*2 : (1<<23)*4; unsigned MaxDisp = (Br.UncondBr == ARM::tB) ? (1<<10)*2 : (1<<23)*4;