1 files changed, 8 insertions, 3 deletions

diff --git a/contrib/llvm-project/llvm/lib/CodeGen/MachineSink.cpp b/contrib/llvm-project/llvm/lib/CodeGen/MachineSink.cpp
index 54c478645dcf..0dbbc218e946 100644
--- a/contrib/llvm-project/llvm/lib/CodeGen/MachineSink.cpp
+++ b/contrib/llvm-project/llvm/lib/CodeGen/MachineSink.cpp
@@ -796,9 +796,14 @@ bool MachineSinking::isProfitableToSinkTo(Register Reg, MachineInstr &MI,
     if (Reg == 0)
       continue;
 
-    // Don't handle physical register.
-    if (Register::isPhysicalRegister(Reg))
+    if (Register::isPhysicalRegister(Reg)) {
+      if (MO.isUse() &&
+          (MRI->isConstantPhysReg(Reg) || TII->isIgnorableUse(MO)))
+        continue;
+
+      // Don't handle non-constant and non-ignorable physical register.
       return false;
+    }
 
     // Users for the defs are all dominated by SuccToSinkTo.
     if (MO.isDef()) {
@@ -898,7 +903,7 @@ MachineSinking::FindSuccToSinkTo(MachineInstr &MI, MachineBasicBlock *MBB,
         // If the physreg has no defs anywhere, it's just an ambient register
         // and we can freely move its uses. Alternatively, if it's allocatable,
         // it could get allocated to something with a def during allocation.
-        if (!MRI->isConstantPhysReg(Reg))
+        if (!MRI->isConstantPhysReg(Reg) && !TII->isIgnorableUse(MO))
           return nullptr;
       } else if (!MO.isDead()) {
         // A def that isn't dead. We can't move it.