AArch64: implement copies to/from NZCV as a last ditch effort.
A test in test/Generic creates a DAG where the NZCV output of an ADCS is used
by multiple nodes. This makes LLVM want to save a copy of NZCV for later, which
it couldn't do before.
This should be the last fix required for the aarch64 buildbot.
llvm-svn: 209651
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
index 52e3b33..ff115c0 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -1507,7 +1507,25 @@
return;
}
- assert(0 && "unimplemented reg-to-reg copy");
+ if (DestReg == AArch64::NZCV) {
+ assert(AArch64::GPR64RegClass.contains(SrcReg) && "Invalid NZCV copy");
+ BuildMI(MBB, I, DL, get(AArch64::MSR))
+ .addImm(AArch64SysReg::NZCV)
+ .addReg(SrcReg, getKillRegState(KillSrc))
+ .addReg(AArch64::NZCV, RegState::Implicit | RegState::Define);
+ return;
+ }
+
+ if (SrcReg == AArch64::NZCV) {
+ assert(AArch64::GPR64RegClass.contains(DestReg) && "Invalid NZCV copy");
+ BuildMI(MBB, I, DL, get(AArch64::MRS))
+ .addReg(DestReg)
+ .addImm(AArch64SysReg::NZCV)
+ .addReg(AArch64::NZCV, RegState::Implicit | getKillRegState(KillSrc));
+ return;
+ }
+
+ llvm_unreachable("unimplemented reg-to-reg copy");
}
void AArch64InstrInfo::storeRegToStackSlot(