This patch is from julialang repository:
  https://github.com/JuliaLang/julia/commit/47f9139e.patch
but reference comes form ARCH Linux juia package
  https://github.com/archlinux/svntogit-community/tree/packages/julia/trunk

From 47f9139e88917813cb7beee5e690c48c2ac65de4 Mon Sep 17 00:00:00 2001
From: Xuanda Yang <th3charlie@gmail.com>
Date: Wed, 9 Jun 2021 22:35:14 +0800
Subject: [PATCH] codegen: replace deprecated llvm::VectorType::getNumElements
 with new APIs (#41144)

---
 src/llvm-late-gc-lowering.cpp | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/src/llvm-late-gc-lowering.cpp b/src/llvm-late-gc-lowering.cpp
index 50015045151b..4df303462d96 100644
--- a/src/llvm-late-gc-lowering.cpp
+++ b/src/llvm-late-gc-lowering.cpp
@@ -396,8 +396,14 @@ CountTrackedPointers::CountTrackedPointers(Type *T) {
         }
         if (isa<ArrayType>(T))
             count *= cast<ArrayType>(T)->getNumElements();
-        else if (isa<VectorType>(T))
+        else if (isa<VectorType>(T)) {
+#if JL_LLVM_VERSION >= 120000
+            ElementCount EC = cast<VectorType>(T)->getElementCount();
+            count *= EC.getKnownMinValue();
+#else
             count *= cast<VectorType>(T)->getNumElements();
+#endif
+        }
     }
     if (count == 0)
         all = false;
@@ -408,8 +414,14 @@ unsigned getCompositeNumElements(Type *T) {
         return ST->getNumElements();
     else if (auto *AT = dyn_cast<ArrayType>(T))
         return AT->getNumElements();
-    else
+    else {
+#if JL_LLVM_VERSION >= 120000
+        ElementCount EC = cast<VectorType>(T)->getElementCount();
+        return EC.getKnownMinValue();
+#else
         return cast<VectorType>(T)->getNumElements();
+#endif
+    }
 }
 
 // Walk through a Type, and record the element path to every tracked value inside
@@ -625,8 +637,14 @@ void LateLowerGCFrame::LiftSelect(State &S, SelectInst *SI) {
     }
     std::vector<int> Numbers;
     unsigned NumRoots = 1;
-    if (auto VTy = dyn_cast<VectorType>(SI->getType()))
+    if (auto VTy = dyn_cast<VectorType>(SI->getType())) {
+#if JL_LLVM_VERSION >= 120000
+        ElementCount EC = VTy->getElementCount();
+        Numbers.resize(EC.getKnownMinValue(), -1);
+#else
         Numbers.resize(VTy->getNumElements(), -1);
+#endif
+    }
     else
         assert(isa<PointerType>(SI->getType()) && "unimplemented");
     assert(!isTrackedValue(SI));
@@ -686,7 +704,12 @@ void LateLowerGCFrame::LiftSelect(State &S, SelectInst *SI) {
             assert(NumRoots == 1);
             int Number = Numbers[0];
             Numbers.resize(0);
+#if JL_LLVM_VERSION >= 120000
+            ElementCount EC = VTy->getElementCount();
+            Numbers.resize(EC.getKnownMinValue(), Number);
+#else
             Numbers.resize(VTy->getNumElements(), Number);
+#endif
         }
     }
     if (!isa<PointerType>(SI->getType()))