diff --git a/llvm/include/llvm/IR/BasicBlock.h b/llvm/include/llvm/IR/BasicBlock.h
--- a/llvm/include/llvm/IR/BasicBlock.h
+++ b/llvm/include/llvm/IR/BasicBlock.h
@@ -196,6 +196,15 @@
                                           ->getFirstInsertionPt().getNonConst();
   }
 
+  /// Returns an iterator to the first instruction in this block that is
+  /// not a PHINode, a debug intrinsic, a static alloca or any pseudo operation.
+  const_iterator getFirstNonPHIOrDbgOrAlloca() const;
+  iterator getFirstNonPHIOrDbgOrAlloca() {
+    return static_cast<const BasicBlock *>(this)
+        ->getFirstNonPHIOrDbgOrAlloca()
+        .getNonConst();
+  }
+
   /// Return a const iterator range over the instructions in the block, skipping
   /// any debug instructions. Skip any pseudo operations as well if \c
   /// SkipPseudoOp is true.
diff --git a/llvm/include/llvm/IR/IRBuilder.h b/llvm/include/llvm/IR/IRBuilder.h
--- a/llvm/include/llvm/IR/IRBuilder.h
+++ b/llvm/include/llvm/IR/IRBuilder.h
@@ -199,6 +199,14 @@
       SetCurrentDebugLocation(IP->getDebugLoc());
   }
 
+  /// This specifies that created instructions should inserted at the beginning
+  /// end of the specified function, but after already existing static alloca
+  /// instructions that are at the start.
+  void SetInsertPointPastAllocas(Function *F) {
+    BB = &F->getEntryBlock();
+    InsertPt = BB->getFirstNonPHIOrDbgOrAlloca();
+  }
+
   /// Set location information used by debugging information.
   void SetCurrentDebugLocation(DebugLoc L) {
     AddOrRemoveMetadataToCopy(LLVMContext::MD_dbg, L.getAsMDNode());
diff --git a/llvm/lib/CodeGen/ShadowStackGCLowering.cpp b/llvm/lib/CodeGen/ShadowStackGCLowering.cpp
--- a/llvm/lib/CodeGen/ShadowStackGCLowering.cpp
+++ b/llvm/lib/CodeGen/ShadowStackGCLowering.cpp
@@ -320,9 +320,8 @@
   Instruction *StackEntry =
       AtEntry.CreateAlloca(ConcreteStackEntryTy, nullptr, "gc_frame");
 
-  while (isa<AllocaInst>(IP))
-    ++IP;
-  AtEntry.SetInsertPoint(IP->getParent(), IP);
+  AtEntry.SetInsertPointPastAllocas(&F);
+  IP = AtEntry.GetInsertPoint();
 
   // Initialize the map pointer and load the current head of the shadow stack.
   Instruction *CurrentHead =
diff --git a/llvm/lib/IR/BasicBlock.cpp b/llvm/lib/IR/BasicBlock.cpp
--- a/llvm/lib/IR/BasicBlock.cpp
+++ b/llvm/lib/IR/BasicBlock.cpp
@@ -253,6 +253,30 @@
   return InsertPt;
 }
 
+BasicBlock::const_iterator BasicBlock::getFirstNonPHIOrDbgOrAlloca() const {
+  const Instruction *FirstNonPHI = getFirstNonPHI();
+  if (!FirstNonPHI)
+    return end();
+
+  const_iterator InsertPt = FirstNonPHI->getIterator();
+  if (InsertPt->isEHPad())
+    ++InsertPt;
+
+  if (isEntryBlock()) {
+    const_iterator End = end();
+    while (InsertPt != End &&
+           (isa<AllocaInst>(*InsertPt) || isa<DbgInfoIntrinsic>(*InsertPt) ||
+            isa<PseudoProbeInst>(*InsertPt))) {
+      if (const AllocaInst *AI = dyn_cast<AllocaInst>(&*InsertPt)) {
+        if (!AI->isStaticAlloca())
+          break;
+      }
+      ++InsertPt;
+    }
+  }
+  return InsertPt;
+}
+
 void BasicBlock::dropAllReferences() {
   for (Instruction &I : *this)
     I.dropAllReferences();
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3937,9 +3937,8 @@
   // replacement below is still necessary.
   Instruction *MoveBefore;
   if (isa<Argument>(Op)) {
-    MoveBefore = &FI.getFunction()->getEntryBlock().front();
-    while (isa<AllocaInst>(MoveBefore))
-      MoveBefore = MoveBefore->getNextNode();
+    MoveBefore =
+        &*FI.getFunction()->getEntryBlock().getFirstNonPHIOrDbgOrAlloca();
   } else {
     MoveBefore = cast<Instruction>(Op)->getInsertionPointAfterDef();
     if (!MoveBefore)