diff --git a/llvm/lib/Transforms/Scalar/SCCP.cpp b/llvm/lib/Transforms/Scalar/SCCP.cpp
--- a/llvm/lib/Transforms/Scalar/SCCP.cpp
+++ b/llvm/lib/Transforms/Scalar/SCCP.cpp
@@ -533,17 +533,14 @@
 
     auto Iter = AdditionalUsers.find(I);
     if (Iter != AdditionalUsers.end()) {
-      // Cache Instructions to update and update later
-      // in order to avoid iterator invalidation
-      SmallPtrSet<Instruction *, 2> toNotify;
-      for (User *U : Iter->second) {
-        if (auto *UI = dyn_cast<Instruction>(U)) {
-          toNotify.insert(UI);
-        }
-      }
-      for (Instruction *UI : toNotify) {
+      // Copy additional users before notifying them of changes, because new
+      // users may be added, potentially invalidating the iterator.
+      SmallVector<Instruction *, 2> ToNotify;
+      for (User *U : Iter->second)
+        if (auto *UI = dyn_cast<Instruction>(U))
+          ToNotify.push_back(UI);
+      for (Instruction *UI : ToNotify)
         OperandChangedState(UI);
-      }
     }
   }
   void handleCallOverdefined(CallBase &CB);
diff --git a/llvm/test/Transforms/SCCP/pr49582-iterator-invalidation.ll b/llvm/test/Transforms/SCCP/pr49582-iterator-invalidation.ll
--- a/llvm/test/Transforms/SCCP/pr49582-iterator-invalidation.ll
+++ b/llvm/test/Transforms/SCCP/pr49582-iterator-invalidation.ll
@@ -1,10 +1,11 @@
 ; RUN: opt < %s -ipsccp -disable-output
-; PR49582
+; PR49582: This test checks for an iterator invalidation issue, which only gets
+; exposed on a large-enough test case. We intentionally do not check the output.
 
 @c = external dso_local global i32*, align 8
 @d = external dso_local global i32, align 4
 
-define dso_local void @_Z1hi(i32 %i) #0 {
+define void @f(i32 %i) {
 entry:
   br label %for.cond
 
@@ -147,7 +148,7 @@
   br label %if.end628
 
 if.else78:                                        ; preds = %if.then
-  %call = call i32 @_Z1biii()
+  %call = call i32 @g()
   %tobool79 = icmp ne i32 %call, 0
   br i1 %tobool79, label %if.then80, label %if.else123
 
@@ -214,12 +215,12 @@
   br label %if.end628
 
 if.else123:                                       ; preds = %if.else78
-  %call124 = call i32 @_Z1biii()
+  %call124 = call i32 @g()
   %tobool125 = icmp ne i32 %call124, 0
   br i1 %tobool125, label %if.then126, label %if.end628
 
 if.then126:                                       ; preds = %if.else123
-  %call127 = call i32 @_Z1biii()
+  %call127 = call i32 @g()
   %tobool128 = icmp ne i32 %call127, 0
   br i1 %tobool128, label %if.then129, label %if.else164
 
@@ -320,7 +321,7 @@
   br label %if.end628
 
 if.else205:                                       ; preds = %if.else195
-  %call206 = call i32 @_Z1aii()
+  %call206 = call i32 @h()
   %tobool207 = icmp ne i32 %call206, 0
   br i1 %tobool207, label %if.then208, label %if.else217
 
@@ -352,7 +353,7 @@
   br label %if.end628
 
 if.else227:                                       ; preds = %if.else217
-  %call228 = call i32 @_Z1biii()
+  %call228 = call i32 @g()
   %tobool229 = icmp ne i32 %call228, 0
   br i1 %tobool229, label %if.then230, label %if.else245
 
@@ -405,7 +406,7 @@
   br label %if.end628
 
 if.else268:                                       ; preds = %if.else258
-  %call269 = call i32 @_Z1aii()
+  %call269 = call i32 @h()
   %tobool270 = icmp ne i32 %call269, 0
   br i1 %tobool270, label %if.then271, label %if.else279
 
@@ -432,7 +433,7 @@
   br label %if.end628
 
 if.else287:                                       ; preds = %if.else279
-  %call288 = call i32 @_Z1biii()
+  %call288 = call i32 @g()
   %tobool289 = icmp ne i32 %call288, 0
   br i1 %tobool289, label %if.then290, label %if.else307
 
@@ -480,7 +481,7 @@
   br label %if.end628
 
 if.else324:                                       ; preds = %if.else307
-  %call325 = call i32 @_Z1biii()
+  %call325 = call i32 @g()
   %tobool326 = icmp ne i32 %call325, 0
   br i1 %tobool326, label %if.then327, label %if.else475
 
@@ -521,7 +522,7 @@
 
 if.end344:                                        ; preds = %if.then342, %if.end340
   %e.14 = phi i32 [ %inc343, %if.then342 ], [ %e.13, %if.end340 ]
-  %call345 = call i32 @_Z1biii()
+  %call345 = call i32 @g()
   %tobool346 = icmp ne i32 %call345, 0
   br i1 %tobool346, label %if.then347, label %if.else398
 
@@ -593,7 +594,7 @@
   br label %if.end628
 
 if.else398:                                       ; preds = %if.end344
-  %call399 = call i32 @_Z1aii()
+  %call399 = call i32 @h()
   %tobool400 = icmp ne i32 %call399, 0
   br i1 %tobool400, label %if.then401, label %if.else409
 
@@ -607,7 +608,7 @@
   br label %if.end628
 
 if.else409:                                       ; preds = %if.else398
-  %call410 = call i32 @_Z1aii()
+  %call410 = call i32 @h()
   %tobool411 = icmp ne i32 %call410, 0
   br i1 %tobool411, label %if.then412, label %if.else420
 
@@ -621,7 +622,7 @@
   br label %if.end628
 
 if.else420:                                       ; preds = %if.else409
-  %call421 = call i32 @_Z1aii()
+  %call421 = call i32 @h()
   %tobool422 = icmp ne i32 %call421, 0
   br i1 %tobool422, label %if.then423, label %if.else431
 
@@ -635,7 +636,7 @@
   br label %if.end628
 
 if.else431:                                       ; preds = %if.else420
-  %call432 = call i32 @_Z1aii()
+  %call432 = call i32 @h()
   %tobool433 = icmp ne i32 %call432, 0
   br i1 %tobool433, label %if.then434, label %if.else440
 
@@ -648,7 +649,7 @@
   br label %if.end628
 
 if.else440:                                       ; preds = %if.else431
-  %call441 = call i32 @_Z1aii()
+  %call441 = call i32 @h()
   %tobool442 = icmp ne i32 %call441, 0
   br i1 %tobool442, label %if.then443, label %if.else451
 
@@ -664,7 +665,7 @@
   br label %if.end628
 
 if.else451:                                       ; preds = %if.else440
-  %call452 = call i32 @_Z1aii()
+  %call452 = call i32 @h()
   %tobool453 = icmp ne i32 %call452, 0
   br i1 %tobool453, label %if.then454, label %if.else460
 
@@ -686,12 +687,12 @@
   br label %if.end628
 
 if.else475:                                       ; preds = %if.else324
-  %call476 = call i32 @_Z1biii()
+  %call476 = call i32 @g()
   %tobool477 = icmp ne i32 %call476, 0
   br i1 %tobool477, label %if.then478, label %if.else509
 
 if.then478:                                       ; preds = %if.else475
-  %call479 = call i32 @_Z1aii()
+  %call479 = call i32 @h()
   %tobool480 = icmp ne i32 %call479, 0
   br i1 %tobool480, label %if.then481, label %if.else487
 
@@ -704,7 +705,7 @@
   br label %if.end628
 
 if.else487:                                       ; preds = %if.then478
-  %call488 = call i32 @_Z1aii()
+  %call488 = call i32 @h()
   %tobool489 = icmp ne i32 %call488, 0
   br i1 %tobool489, label %if.then490, label %if.else496
 
@@ -731,7 +732,7 @@
   br label %if.end628
 
 if.else509:                                       ; preds = %if.else475
-  %call510 = call i32 @_Z1biii()
+  %call510 = call i32 @g()
   %tobool511 = icmp ne i32 %call510, 0
   br i1 %tobool511, label %if.then512, label %if.else565
 
@@ -792,7 +793,7 @@
   br label %if.end628
 
 if.else565:                                       ; preds = %if.else509
-  %call566 = call i32 @_Z1biii()
+  %call566 = call i32 @g()
   %tobool567 = icmp ne i32 %call566, 0
   br i1 %tobool567, label %if.then568, label %if.else590
 
@@ -819,7 +820,7 @@
   br label %if.end628
 
 if.else590:                                       ; preds = %if.else565
-  %call591 = call i32 @_Z1biii()
+  %call591 = call i32 @g()
   %tobool592 = icmp ne i32 %call591, 0
   br i1 %tobool592, label %if.then593, label %if.end628
 
@@ -844,16 +845,10 @@
   br label %for.cond
 }
 
-declare dso_local i32 @_Z1biii() #0
+declare i32 @g()
 
-declare dso_local i32 @_Z1aii() #0
+declare i32 @h()
 
 ; Function Attrs: nofree nosync nounwind willreturn
 declare void @llvm.assume(i1 noundef) #1
 
-attributes #0 = { "tune-cpu"="generic" }
-attributes #1 = { nofree nosync nounwind willreturn }
-
-!llvm.ident = !{!0}
-
-!0 = !{!"clang version 13.0.0 (https://github.com/llvm/llvm-project.git 29d46760599b32504f4dfda4de69aca8b9f1f65e)"}