Expands register/immediate pairs when the immediate is too large to fit in 16-bit field. Patch by Akira Hatanaka
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127032 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsFrameLowering.cpp b/lib/Target/Mips/MipsFrameLowering.cpp
index 87a097a..bf37032 100644
--- a/lib/Target/Mips/MipsFrameLowering.cpp
+++ b/lib/Target/Mips/MipsFrameLowering.cpp
@@ -203,6 +203,43 @@
MipsFI->setFPUTopSavedRegOff(TopFPUSavedRegOff-StackOffset);
}
+
+// expand pair of register and immediate if the immediate doesn't fit in the 16-bit
+// offset field.
+// e.g.
+// if OrigImm = 0x10000, OrigReg = $sp:
+// generate the following sequence of instrs:
+// lui $at, hi(0x10000)
+// addu $at, $sp, $at
+//
+// (NewReg, NewImm) = ($at, lo(Ox10000))
+// return true
+static bool expandRegLargeImmPair(unsigned OrigReg, int OrigImm,
+ unsigned& NewReg, int& NewImm,
+ MachineBasicBlock& MBB, MachineBasicBlock::iterator I) {
+ // OrigImm fits in the 16-bit field
+ if (OrigImm < 0x8000 && OrigImm >= -0x8000) {
+ NewReg = OrigReg;
+ NewImm = OrigImm;
+ return false;
+ }
+
+ MachineFunction* MF = MBB.getParent();
+ const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
+ DebugLoc DL = I->getDebugLoc();
+ int ImmLo = OrigImm & 0xffff;
+ int ImmHi = (((unsigned)OrigImm & 0xffff0000) >> 16) + ((OrigImm & 0x8000) != 0);
+
+ // FIXME: change this when mips goes MC".
+ BuildMI(MBB, I, DL, TII->get(Mips::NOAT));
+ BuildMI(MBB, I, DL, TII->get(Mips::LUi), Mips::AT).addImm(ImmHi);
+ BuildMI(MBB, I, DL, TII->get(Mips::ADDu), Mips::AT).addReg(OrigReg).addReg(Mips::AT);
+ NewReg = Mips::AT;
+ NewImm = ImmLo;
+
+ return true;
+}
+
void MipsFrameLowering::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineFrameInfo *MFI = MF.getFrameInfo();
@@ -214,6 +251,9 @@
MachineBasicBlock::iterator MBBI = MBB.begin();
DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
bool isPIC = (MF.getTarget().getRelocationModel() == Reloc::PIC_);
+ unsigned NewReg = 0;
+ int NewImm = 0;
+ bool ATUsed;
// Get the right frame order for Mips.
adjustMipsStackFrame(MF);
@@ -236,22 +276,38 @@
BuildMI(MBB, MBBI, dl, TII.get(Mips::NOMACRO));
// Adjust stack : addi sp, sp, (-imm)
+ ATUsed = expandRegLargeImmPair(Mips::SP, -StackSize, NewReg, NewImm, MBB,
+ MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDiu), Mips::SP)
- .addReg(Mips::SP).addImm(-StackSize);
+ .addReg(NewReg).addImm(NewImm);
+
+ // FIXME: change this when mips goes MC".
+ if (ATUsed)
+ BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
// Save the return address only if the function isnt a leaf one.
// sw $ra, stack_loc($sp)
if (MFI->adjustsStack()) {
+ expandRegLargeImmPair(Mips::SP, RAOffset, NewReg, NewImm, MBB, MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::SW))
- .addReg(Mips::RA).addImm(RAOffset).addReg(Mips::SP);
+ .addReg(Mips::RA).addImm(NewImm).addReg(NewReg);
+
+ // FIXME: change this when mips goes MC".
+ if (ATUsed)
+ BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
}
// if framepointer enabled, save it and set it
// to point to the stack pointer
if (hasFP(MF)) {
// sw $fp,stack_loc($sp)
+ expandRegLargeImmPair(Mips::SP, FPOffset, NewReg, NewImm, MBB, MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::SW))
- .addReg(Mips::FP).addImm(FPOffset).addReg(Mips::SP);
+ .addReg(Mips::FP).addImm(NewImm).addReg(NewReg);
+
+ // FIXME: change this when mips goes MC".
+ if (ATUsed)
+ BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
// move $fp, $sp
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::FP)
@@ -280,6 +336,10 @@
int FPOffset = MipsFI->getFPStackOffset();
int RAOffset = MipsFI->getRAStackOffset();
+ unsigned NewReg = 0;
+ int NewImm = 0;
+ bool ATUsed;
+
// if framepointer enabled, restore it and restore the
// stack pointer
if (hasFP(MF)) {
@@ -288,21 +348,37 @@
.addReg(Mips::FP).addReg(Mips::ZERO);
// lw $fp,stack_loc($sp)
+ ATUsed = expandRegLargeImmPair(Mips::SP, FPOffset, NewReg, NewImm, MBB,
+ MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::FP)
- .addImm(FPOffset).addReg(Mips::SP);
+ .addImm(NewImm).addReg(NewReg);
+
+ // FIXME: change this when mips goes MC".
+ if (ATUsed)
+ BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
}
// Restore the return address only if the function isnt a leaf one.
// lw $ra, stack_loc($sp)
if (MFI->adjustsStack()) {
+ expandRegLargeImmPair(Mips::SP, RAOffset, NewReg, NewImm, MBB, MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::RA)
- .addImm(RAOffset).addReg(Mips::SP);
+ .addImm(NewImm).addReg(NewReg);
+
+ // FIXME: change this when mips goes MC".
+ if (ATUsed)
+ BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
}
// adjust stack : insert addi sp, sp, (imm)
if (NumBytes) {
+ expandRegLargeImmPair(Mips::SP, NumBytes, NewReg, NewImm, MBB, MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDiu), Mips::SP)
- .addReg(Mips::SP).addImm(NumBytes);
+ .addReg(NewReg).addImm(NewImm);
+
+ // FIXME: change this when mips goes MC".
+ if (ATUsed)
+ BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
}
}