From 42e90cf4bebbf24d2303d34ce03c2a0070328557 Mon Sep 17 00:00:00 2001 From: "Vikram S. Adve" Date: Sun, 13 Oct 2002 00:24:06 +0000 Subject: [PATCH] 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 --- lib/Target/SparcV9/SparcV9PrologEpilogInserter.cpp | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/lib/Target/SparcV9/SparcV9PrologEpilogInserter.cpp b/lib/Target/SparcV9/SparcV9PrologEpilogInserter.cpp index cfa71f663c3..75146c072ed 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);