Materialize global addresses via movt/movw pair, this is always better
than doing the same via constpool:
1. Load from constpool costs 3 cycles on A9, movt/movw pair - just 2.
2. Load from constpool might stall up to 300 cycles due to cache miss.
3. Movt/movw does not use load/store unit.
4. Less constpool entries => better compiler performance.
This is only enabled on ELF systems, since darwin does not have needed
relocations (yet).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89720 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMExpandPseudoInsts.cpp b/lib/Target/ARM/ARMExpandPseudoInsts.cpp
index 4d0f899..c929c54 100644
--- a/lib/Target/ARM/ARMExpandPseudoInsts.cpp
+++ b/lib/Target/ARM/ARMExpandPseudoInsts.cpp
@@ -75,17 +75,30 @@
}
case ARM::t2MOVi32imm: {
unsigned DstReg = MI.getOperand(0).getReg();
- unsigned Imm = MI.getOperand(1).getImm();
- unsigned Lo16 = Imm & 0xffff;
- unsigned Hi16 = (Imm >> 16) & 0xffff;
if (!MI.getOperand(0).isDead()) {
- AddDefaultPred(BuildMI(MBB, MBBI, MI.getDebugLoc(),
- TII->get(ARM::t2MOVi16), DstReg)
- .addImm(Lo16));
- AddDefaultPred(BuildMI(MBB, MBBI, MI.getDebugLoc(),
- TII->get(ARM::t2MOVTi16))
- .addReg(DstReg, getDefRegState(true))
- .addReg(DstReg).addImm(Hi16));
+ const MachineOperand &MO = MI.getOperand(1);
+ MachineInstrBuilder LO16, HI16;
+
+ LO16 = BuildMI(MBB, MBBI, MI.getDebugLoc(), TII->get(ARM::t2MOVi16),
+ DstReg);
+ HI16 = BuildMI(MBB, MBBI, MI.getDebugLoc(), TII->get(ARM::t2MOVTi16))
+ .addReg(DstReg, getDefRegState(true)).addReg(DstReg);
+
+ if (MO.isImm()) {
+ unsigned Imm = MO.getImm();
+ unsigned Lo16 = Imm & 0xffff;
+ unsigned Hi16 = (Imm >> 16) & 0xffff;
+ LO16 = LO16.addImm(Lo16);
+ HI16 = HI16.addImm(Hi16);
+ } else {
+ GlobalValue *GV = MO.getGlobal();
+ unsigned TF = MO.getTargetFlags();
+ LO16 = LO16.addGlobalAddress(GV, MO.getOffset(), TF | ARMII::MO_LO16);
+ HI16 = HI16.addGlobalAddress(GV, MO.getOffset(), TF | ARMII::MO_HI16);
+ // FIXME: What's about memoperands?
+ }
+ AddDefaultPred(LO16);
+ AddDefaultPred(HI16);
}
MI.eraseFromParent();
Modified = true;