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Refactor rewinding code for finding the first terminator of a basic

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block into MachineBasicBlock::getFirstTerminator().

This also fixes a bug in the implementation of the above in both
RegAllocLocal and InstrSched, where instructions where added after the
terminator if the basic block's only instruction was a terminator (it
shouldn't matter for RegAllocLocal since this case never occurs in
practice).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11748 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Alkis Evlogimenos
2004-02-23 18:14:48 +00:00
parent fbc39d5045
commit 743d0a1f83
6 changed files with 21 additions and 33 deletions
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17
lib/CodeGen/PHIElimination.cpp
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@@ -143,22 +143,7 @@ bool PNE::EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB) {
// source path the PHI.
MachineBasicBlock &opBlock = *MI->getOperand(i).getMachineBasicBlock();
// Figure out where to insert the copy, which is at the end of the
// predecessor basic block, but before any terminator/branch
// instructions...
MachineBasicBlock::iterator I = opBlock.end();
if (I != opBlock.begin()) { // Handle empty blocks
--I;
// must backtrack over ALL the branches in the previous block
while (MII.isTerminatorInstr(I->getOpcode()) &&
I != opBlock.begin())
--I;
// move back to the first branch instruction so new instructions
// are inserted right in front of it and not in front of a non-branch
if (!MII.isTerminatorInstr(I->getOpcode()))
++I;
}
MachineBasicBlock::iterator I = opBlock.getFirstTerminator();
// Check to make sure we haven't already emitted the copy for this block.
// This can happen because PHI nodes may have multiple entries for the