Index: lib/Target/X86/X86OptimizeLEAs.cpp
===================================================================
--- lib/Target/X86/X86OptimizeLEAs.cpp
+++ lib/Target/X86/X86OptimizeLEAs.cpp
@@ -514,8 +514,14 @@
     MachineInstr *DefMI;
     int64_t AddrDispShift;
     int Dist;
-    if (!chooseBestLEA(LEAs[getMemOpKey(MI, MemOpNo)], MI, DefMI, AddrDispShift,
-                       Dist))
+    MemOpKey key = getMemOpKey(MI, MemOpNo);
+    auto insns = LEAs.find(key);
+
+    // Do not call chooseBestLEA if there was no matching LEA
+    if (insns == LEAs.end())
+      continue;
+
+    if (!chooseBestLEA(insns->second, MI, DefMI, AddrDispShift, Dist))
       continue;
 
     // If LEA occurs before current instruction, we can freely replace