Don't use %l0 for large operands to a SAVE since it is needed *before* SAVE!

We now use %g1 instead since that is shared and volatile.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4133 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Vikram S. Adve 2002-10-13 00:24:06 +00:00
parent e0048667dd
commit 42e90cf4be

View File

@ -58,15 +58,14 @@ void InsertPrologEpilogCode::InsertPrologCode(Function &F)
// The second operand is the stack size. If it does not fit in the
// immediate field, we have to use a free register to hold the size.
// We will assume that local register `l0' is unused since the SAVE
// instruction must be the first instruction in each procedure.
// See the comments below for the choice of this register.
//
MachineCodeForMethod& mcInfo = MachineCodeForMethod::get(&F);
unsigned int staticStackSize = mcInfo.getStaticStackSize();
if (staticStackSize < (unsigned) frameInfo.getMinStackFrameSize())
staticStackSize = (unsigned) frameInfo.getMinStackFrameSize();
if (unsigned padsz = (staticStackSize %
(unsigned) frameInfo.getStackFrameSizeAlignment()))
staticStackSize += frameInfo.getStackFrameSizeAlignment() - padsz;
@ -83,13 +82,14 @@ void InsertPrologEpilogCode::InsertPrologCode(Function &F)
else
{
// We have to put the stack size value into a register before SAVE.
// Use register %l0 to since it must be unused at function entry.
// Use register %g1 since it is volatile across calls. Note that the
// local (%l) and in (%i) registers cannot be used before the SAVE!
// Do this by creating a code sequence equivalent to:
// SETSW -(stackSize), %l0
// SETSW -(stackSize), %g1
int32_t C = - (int) staticStackSize;
int uregNum = Target.getRegInfo().getUnifiedRegNum(
Target.getRegInfo().getRegClassIDOfType(Type::IntTy),
SparcIntRegClass::l0);
SparcIntRegClass::g1);
M = new MachineInstr(SETHI);
M->SetMachineOperandConst(0, MachineOperand::MO_SignExtendedImmed, C);
@ -110,7 +110,7 @@ void InsertPrologEpilogCode::InsertPrologCode(Function &F)
M->SetMachineOperandReg(2, uregNum);
mvec.push_back(M);
// Now generate the SAVE using the value in register %l0
// Now generate the SAVE using the value in register %g1
M = new MachineInstr(SAVE);
M->SetMachineOperandReg(0, Target.getRegInfo().getStackPointer());
M->SetMachineOperandReg(1, uregNum);