Index: ELF/LinkerScript.h
===================================================================
--- ELF/LinkerScript.h
+++ ELF/LinkerScript.h
@@ -271,7 +271,7 @@
   bool needsInterpSection();
 
   bool shouldKeep(InputSectionBase *s);
-  void assignAddresses();
+  const Defined *assignAddresses();
   void allocateHeaders(std::vector<PhdrEntry *> &phdrs);
   void processSectionCommands();
   void declareSymbols();
Index: ELF/LinkerScript.cpp
===================================================================
--- ELF/LinkerScript.cpp
+++ ELF/LinkerScript.cpp
@@ -1054,7 +1054,9 @@
 // Here we assign addresses as instructed by linker script SECTIONS
 // sub-commands. Doing that allows us to use final VA values, so here
 // we also handle rest commands like symbol assignments and ASSERTs.
-void LinkerScript::assignAddresses() {
+// Returns a symbol that has changed its section or value, or nullptr if no
+// symbol has changed.
+const Defined *LinkerScript::assignAddresses() {
   dot = getInitialDot();
 
   auto deleter = std::make_unique<AddressState>();
@@ -1062,6 +1064,13 @@
   errorOnMissingSection = true;
   switchTo(aether);
 
+  DenseMap<const Defined *, std::pair<SectionBase *, uint64_t>> old;
+  for (BaseCommand *base : sectionCommands)
+    if (auto *cmd = dyn_cast<SymbolAssignment>(base))
+      if (cmd->sym)
+        old.try_emplace(cmd->sym,
+                        std::make_pair(cmd->sym->section, cmd->sym->value));
+
   for (BaseCommand *base : sectionCommands) {
     if (auto *cmd = dyn_cast<SymbolAssignment>(base)) {
       cmd->addr = dot;
@@ -1072,6 +1081,17 @@
     assignOffsets(cast<OutputSection>(base));
   }
   ctx = nullptr;
+
+  // Return the lexicographical smallest (for determinism) Defined whose
+  // section/value has changed.
+  const Defined *changed = nullptr;
+  for (auto &it : old) {
+    const Defined *sym = it.first;
+    if ((sym->section != it.second.first || sym->value != it.second.second) &&
+        (!changed || sym->getName() < changed->getName()))
+      return sym;
+  }
+  return nullptr;
 }
 
 // Creates program headers as instructed by PHDRS linker script command.
Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -580,8 +580,6 @@
   if (errorCount())
     return;
 
-  script->assignAddresses();
-
   // If -compressed-debug-sections is specified, we need to compress
   // .debug_* sections. Do it right now because it changes the size of
   // output sections.
@@ -1567,15 +1565,12 @@
 template <class ELFT> void Writer<ELFT>::finalizeAddressDependentContent() {
   ThunkCreator tc;
   AArch64Err843419Patcher a64p;
+  script->assignAddresses();
 
   // For some targets, like x86, this loop iterates only once.
+  int tries = 5;
   for (;;) {
-    bool changed = false;
-
-    script->assignAddresses();
-
-    if (target->needsThunks)
-      changed |= tc.createThunks(outputSections);
+    bool changed = target->needsThunks && tc.createThunks(outputSections);
 
     if (config->fixCortexA53Errata843419) {
       if (changed)
@@ -1592,8 +1587,16 @@
         changed |= part.relrDyn->updateAllocSize();
     }
 
-    if (!changed)
-      return;
+    const Defined *changedSym = script->assignAddresses();
+    if (!changed) {
+      if (!changedSym)
+        break;
+      if (--tries == 0) {
+        errorOrWarn("assignment to symbol " + toString(*changedSym) +
+                    " does not converge");
+        break;
+      }
+    }
   }
 }
 
Index: test/ELF/linkerscript/expr-converge.test
===================================================================
--- /dev/null
+++ test/ELF/linkerscript/expr-converge.test
@@ -0,0 +1,13 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64 /dev/null -o %t.o
+# RUN: ld.lld %t.o -T %s -o %t
+# RUN: llvm-nm %t | FileCheck %s
+
+# CHECK: 000000000000ffff T a
+# CHECK: 000000000000ffff T b
+
+a = b;
+SECTIONS {
+  . = 0xffff + (b >> 8) - 0xff;
+  b = .;
+}