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Tighten up the erase/remove API for bundled instructions.

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Most code is oblivious to bundles and uses the MBB::iterator which only
visits whole bundles. MBB::erase() operates on whole bundles at a time
as before.

MBB::remove() now refuses to remove bundled instructions. It is not safe
to remove all instructions in a bundle without deleting them since there
is no way of returning pointers to all the removed instructions.

MBB::remove_instr() and MBB::erase_instr() will now update bundle flags
correctly, lifting individual instructions out of bundles while leaving
the remaining bundle intact.

The MachineInstr convenience functions are updated so

  eraseFromParent() erases a whole bundle as before
  eraseFromBundle() erases a single instruction, leaving the rest of its bundle.
  removeFromParent() refuses to operate on bundled instructions, and
  removeFromBundle() lifts a single instruction out of its bundle.

These functions will no longer accidentally split or coalesce bundles -
bundle flags are updated to preserve the existing bundling, and explicit
bundleWith* / unbundleFrom* functions should be used to change the
instruction bundling.

This API update is still a work in progress. I am going to update APIs
first so they maintain bundle flags automatically when possible. Then
I'll add stricter verification of the bundle flags.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170384 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2012-12-17 23:55:38 +00:00
parent 082b7e6d36
commit 9f4692d295
4 changed files with 96 additions and 75 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/CodeGen/MachineInstr.cpp
+10 -31
View File
@@ -838,46 +838,25 @@ bool MachineInstr::isIdenticalTo(const MachineInstr *Other,
return true;
}
/// removeFromParent - This method unlinks 'this' from the containing basic
/// block, and returns it, but does not delete it.
MachineInstr *MachineInstr::removeFromParent() {
assert(getParent() && "Not embedded in a basic block!");
// If it's a bundle then remove the MIs inside the bundle as well.
if (isBundle()) {
MachineBasicBlock *MBB = getParent();
MachineBasicBlock::instr_iterator MII = *this; ++MII;
MachineBasicBlock::instr_iterator E = MBB->instr_end();
while (MII != E && MII->isInsideBundle()) {
MachineInstr *MI = &*MII;
++MII;
MBB->remove(MI);
}
}
getParent()->remove(this);
return this;
return getParent()->remove(this);
}
MachineInstr *MachineInstr::removeFromBundle() {
assert(getParent() && "Not embedded in a basic block!");
return getParent()->remove_instr(this);
}
/// eraseFromParent - This method unlinks 'this' from the containing basic
/// block, and deletes it.
void MachineInstr::eraseFromParent() {
assert(getParent() && "Not embedded in a basic block!");
// If it's a bundle then remove the MIs inside the bundle as well.
if (isBundle()) {
MachineBasicBlock *MBB = getParent();
MachineBasicBlock::instr_iterator MII = *this; ++MII;
MachineBasicBlock::instr_iterator E = MBB->instr_end();
while (MII != E && MII->isInsideBundle()) {
MachineInstr *MI = &*MII;
++MII;
MBB->erase(MI);
}
}
// Erase the individual instruction, which may itself be inside a bundle.
getParent()->erase_instr(this);
getParent()->erase(this);
}
void MachineInstr::eraseFromBundle() {
assert(getParent() && "Not embedded in a basic block!");
getParent()->erase_instr(this);
}
/// getNumExplicitOperands - Returns the number of non-implicit operands.
///