Remove hack now that Evan fixed it so that the frame pointer isn't saved twice.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75581 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2009-07-14 01:16:18 +00:00
parent 65d1e2b6e7
commit 7d43cd8f3e

View File

@ -691,29 +691,6 @@ void X86RegisterInfo::emitCalleeSavedFrameMoves(MachineFunction &MF,
unsigned Reg = I->getReg();
Offset = MaxOffset - Offset + saveAreaOffset;
// Don't output a new machine move if we're re-saving the frame
// pointer. This happens when the PrologEpilogInserter has inserted an extra
// "PUSH" of the frame pointer -- the "emitPrologue" method automatically
// generates one when frame pointers are used. If we generate a "machine
// move" for this extra "PUSH", the linker will lose track of the fact that
// the frame pointer should have the value of the first "PUSH" when it's
// trying to unwind.
//
// FIXME: This looks inelegant. It's possibly correct, but it's covering up
// another bug. I.e., one where we generate a prolog like this:
//
// pushl %ebp
// movl %esp, %ebp
// pushl %ebp
// pushl %esi
// ...
//
// The immediate re-push of EBP is unnecessary. At the least, it's an
// optimization bug. EBP can be used as a scratch register in certain
// cases, but probably not when we have a frame pointer.
if (HasFP && FramePtr == Reg)
continue;
MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
MachineLocation CSSrc(Reg);
Moves.push_back(MachineMove(LabelId, CSDst, CSSrc));