Add an option to use a virtual register as the global base register instead of
reserving a physical register ($gp or $28) for that purpose.
This will completely eliminate loads that restore the value of $gp after every
function call, if the register allocator assigns a callee-saved register, or
eliminate unnecessary loads if it assigns a temporary register.
example:
.cpload $25 // set $gp.
...
.cprestore 16 // store $gp to stack slot 16($sp).
...
jalr $25 // function call. clobbers $gp.
lw $gp, 16($sp) // not emitted if callee-saved reg is chosen.
...
lw $2, 4($gp)
...
jalr $25 // function call.
lw $gp, 16($sp) // not emitted if $gp is not live after this instruction.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151402 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsMachineFunction.h b/lib/Target/Mips/MipsMachineFunction.h
index 7f5130b..a6e4028 100644
--- a/lib/Target/Mips/MipsMachineFunction.h
+++ b/lib/Target/Mips/MipsMachineFunction.h
@@ -91,8 +91,9 @@
unsigned getSRetReturnReg() const { return SRetReturnReg; }
void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }
- unsigned getGlobalBaseReg() const { return GlobalBaseReg; }
- void setGlobalBaseReg(unsigned Reg) { GlobalBaseReg = Reg; }
+ bool globalBaseRegFixed() const;
+ bool globalBaseRegSet() const;
+ unsigned getGlobalBaseReg();
int getVarArgsFrameIndex() const { return VarArgsFrameIndex; }
void setVarArgsFrameIndex(int Index) { VarArgsFrameIndex = Index; }