aboutsummaryrefslogtreecommitdiff
path: root/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'llvm/lib/Target/RISCV/RISCVFrameLowering.cpp')
-rw-r--r--llvm/lib/Target/RISCV/RISCVFrameLowering.cpp53
1 files changed, 43 insertions, 10 deletions
diff --git a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp b/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
index 23b4554..b1ab76a 100644
--- a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
@@ -1544,10 +1544,53 @@ RISCVFrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
return Offset;
}
+static MCRegister getRVVBaseRegister(const RISCVRegisterInfo &TRI,
+ const Register &Reg) {
+ MCRegister BaseReg = TRI.getSubReg(Reg, RISCV::sub_vrm1_0);
+ // If it's not a grouped vector register, it doesn't have subregister, so
+ // the base register is just itself.
+ if (BaseReg == RISCV::NoRegister)
+ BaseReg = Reg;
+ return BaseReg;
+}
+
void RISCVFrameLowering::determineCalleeSaves(MachineFunction &MF,
BitVector &SavedRegs,
RegScavenger *RS) const {
TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+
+ // In TargetFrameLowering::determineCalleeSaves, any vector register is marked
+ // as saved if any of its subregister is clobbered, this is not correct in
+ // vector registers. We only want the vector register to be marked as saved
+ // if all of its subregisters are clobbered.
+ // For example:
+ // Original behavior: If v24 is marked, v24m2, v24m4, v24m8 are also marked.
+ // Correct behavior: v24m2 is marked only if v24 and v25 are marked.
+ const MachineRegisterInfo &MRI = MF.getRegInfo();
+ const MCPhysReg *CSRegs = MRI.getCalleeSavedRegs();
+ const RISCVRegisterInfo &TRI = *STI.getRegisterInfo();
+ for (unsigned i = 0; CSRegs[i]; ++i) {
+ unsigned CSReg = CSRegs[i];
+ // Only vector registers need special care.
+ if (!RISCV::VRRegClass.contains(getRVVBaseRegister(TRI, CSReg)))
+ continue;
+
+ SavedRegs.reset(CSReg);
+
+ auto SubRegs = TRI.subregs(CSReg);
+ // Set the register and all its subregisters.
+ if (!MRI.def_empty(CSReg) || MRI.getUsedPhysRegsMask().test(CSReg)) {
+ SavedRegs.set(CSReg);
+ llvm::for_each(SubRegs, [&](unsigned Reg) { return SavedRegs.set(Reg); });
+ }
+
+ // Combine to super register if all of its subregisters are marked.
+ if (!SubRegs.empty() && llvm::all_of(SubRegs, [&](unsigned Reg) {
+ return SavedRegs.test(Reg);
+ }))
+ SavedRegs.set(CSReg);
+ }
+
// Unconditionally spill RA and FP only if the function uses a frame
// pointer.
if (hasFP(MF)) {
@@ -2137,16 +2180,6 @@ static unsigned getCalleeSavedRVVNumRegs(const Register &BaseReg) {
: 8;
}
-static MCRegister getRVVBaseRegister(const RISCVRegisterInfo &TRI,
- const Register &Reg) {
- MCRegister BaseReg = TRI.getSubReg(Reg, RISCV::sub_vrm1_0);
- // If it's not a grouped vector register, it doesn't have subregister, so
- // the base register is just itself.
- if (BaseReg == RISCV::NoRegister)
- BaseReg = Reg;
- return BaseReg;
-}
-
void RISCVFrameLowering::emitCalleeSavedRVVPrologCFI(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, bool HasFP) const {
MachineFunction *MF = MBB.getParent();