diff options
| -rw-r--r-- | lib/Target/SparcV9/SparcV9PrologEpilogInserter.cpp | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/lib/Target/SparcV9/SparcV9PrologEpilogInserter.cpp b/lib/Target/SparcV9/SparcV9PrologEpilogInserter.cpp index cfa71f663c..75146c072e 100644 --- a/lib/Target/SparcV9/SparcV9PrologEpilogInserter.cpp +++ b/lib/Target/SparcV9/SparcV9PrologEpilogInserter.cpp @@ -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); |