[llvm] [RegAlloc] Add register allocation anti-hints infrastructure (PR #218071)

[Syadus Sefat via llvm-commits]

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@@ -443,6 +443,41 @@ bool TargetRegisterInfo::getRegAllocationHints(
   return false;
 }
 
+void TargetRegisterInfo::applyRegAllocationAntiHints(
+    Register VirtReg, ArrayRef<MCPhysReg> Order,
+    SmallVectorImpl<MCPhysReg> &HintsAndCustomOrder, unsigned NumHints,
+    SmallVectorImpl<MCPhysReg> &AntiHints, const MachineFunction &MF,
+    const VirtRegMap *VRM, const LiveRegMatrix *Matrix) const {
+
+  if (AntiHints.empty() || !VRM)
+    return;
+
+  auto isAntiHinted = [&](MCPhysReg Reg) {
+    return llvm::any_of(AntiHints, [&](MCPhysReg AntiHint) {
+      return regsOverlap(Reg, AntiHint);
+    });
+  };
+
+  HintsAndCustomOrder.truncate(NumHints);
+  HintsAndCustomOrder.append(Order.begin(), Order.end());
+
+  // Partition non-anti-hinted register go first
----------------
mssefat wrote:

Fixed.

https://github.com/llvm/llvm-project/pull/218071