6beeb09142
Add MachineBasicBlock::addLiveIn().
This function adds a live-in physical register to an MBB and ensures
that it is copied to a virtual register immediately.
Pull in r185615 from llvm trunk:
Live-in copies go *after* EH_LABELs.
This will soon be tested by exception handling working at all.
Pull in r185617 from llvm trunk:
Simplify landing pad lowering.
Stop using the ISD::EXCEPTIONADDR and ISD::EHSELECTION when lowering
landing pad arguments. These nodes were previously legalized into
CopyFromReg nodes, but that never worked properly because the
CopyFromReg node weren't guaranteed to be scheduled at the top of the
basic block.
This meant the exception pointer and selector registers could be
clobbered before being copied to a virtual register.
This patch copies the two physical registers to virtual registers at
the beginning of the basic block, and lowers the landingpad instruction
directly to two CopyFromReg nodes reading the *virtual* registers. This
is safe because virtual registers don't get clobbered.
A future patch will remove the ISD::EXCEPTIONADDR and ISD::EHSELECTION
nodes.
Together, these changes fix llvm PR 16038 ('qt4 webcore file results in
"Bad machine code: Using an undefined physical register"'), and should
make it possible again to compile the www/qt4-webkit port again on the
i386 arch, without using a CPUTYPE=i686 or higher setting.
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| LICENSE.TXT | ||