diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -700,22 +700,22 @@
 
 static ICFLevel getICFLevel(const ArgList &args) {
   bool noDeduplicate = args.hasArg(OPT_no_deduplicate);
-  StringRef icfLevelStr = args.getLastArgValue(OPT_icf);
+  StringRef icfLevelStr = args.getLastArgValue(OPT_icf_eq);
   auto icfLevel = StringSwitch<ICFLevel>(icfLevelStr)
                       .Cases("none", "", ICFLevel::none)
                       .Case("safe", ICFLevel::safe)
                       .Case("all", ICFLevel::all)
                       .Default(ICFLevel::unknown);
   if (icfLevel == ICFLevel::unknown) {
-    warn(Twine("unknown -icf OPTION `") + icfLevelStr +
+    warn(Twine("unknown --icf=OPTION `") + icfLevelStr +
          "', defaulting to `none'");
     icfLevel = ICFLevel::none;
   } else if (icfLevel != ICFLevel::none && noDeduplicate) {
-    warn(Twine("`-icf " + icfLevelStr +
+    warn(Twine("`--icf=" + icfLevelStr +
                "' conflicts with -no_deduplicate, setting to `none'"));
     icfLevel = ICFLevel::none;
   } else if (icfLevel == ICFLevel::safe) {
-    warn(Twine("`-icf safe' is not yet implemented, reverting to `none'"));
+    warn(Twine("`--icf=safe' is not yet implemented, reverting to `none'"));
     icfLevel = ICFLevel::none;
   }
   return icfLevel;
diff --git a/lld/MachO/Options.td b/lld/MachO/Options.td
--- a/lld/MachO/Options.td
+++ b/lld/MachO/Options.td
@@ -60,6 +60,10 @@
 def print_dylib_search: Flag<["--"], "print-dylib-search">,
     HelpText<"Print which paths lld searched when trying to find dylibs">,
     Group<grp_lld>;
+def icf_eq: Joined<["--"], "icf=">,
+    HelpText<"Set level for identical code folding (default: none)">,
+    MetaVarName<"[none,safe,all]">,
+    Group<grp_lld>;
 
 // This is a complete Options.td compiled from Apple's ld(1) manpage
 // dated 2018-03-07 and cross checked with ld64 source code in repo
@@ -275,12 +279,8 @@
     HelpText<"Disable infra for branches beyond the maximum branch distance.">,
     Flags<[HelpHidden]>,
     Group<grp_opts>;
-def icf: Separate<["-"], "icf">,
-    HelpText<"Set level for identical code folding (default: none)">,
-    MetaVarName<"[none,safe,all]">,
-    Group<grp_opts>;
 def no_deduplicate : Flag<["-"], "no_deduplicate">,
-    HelpText<"Disable code deduplicaiton (synonym for `-icf none')">,
+    HelpText<"Disable code deduplicaiton (synonym for `--icf=none')">,
     Group<grp_opts>;
 
 def grp_version : OptionGroup<"version">, HelpText<"VERSION TARGETING">;
diff --git a/lld/test/MachO/icf-options.s b/lld/test/MachO/icf-options.s
--- a/lld/test/MachO/icf-options.s
+++ b/lld/test/MachO/icf-options.s
@@ -2,23 +2,23 @@
 # RUN: rm -rf %t; mkdir %t
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t/main.o
-# RUN: %lld -lSystem -icf all -o %t/all %t/main.o 2>&1 \
+# RUN: %lld -lSystem --icf=all -o %t/all %t/main.o 2>&1 \
 # RUN:     | FileCheck %s --check-prefix=DIAG-EMPTY --allow-empty
-# RUN: %lld -lSystem -icf none -o %t/none %t/main.o 2>&1 \
+# RUN: %lld -lSystem --icf=none -o %t/none %t/main.o 2>&1 \
 # RUN:     | FileCheck %s --check-prefix=DIAG-EMPTY --allow-empty
 # RUN: %lld -lSystem -no_deduplicate -o %t/no_dedup %t/main.o 2>&1 \
 # RUN:     | FileCheck %s --check-prefix=DIAG-EMPTY --allow-empty
-# RUN: not %lld -lSystem -icf safe -o %t/safe %t/main.o 2>&1 \
+# RUN: not %lld -lSystem --icf=safe -o %t/safe %t/main.o 2>&1 \
 # RUN:     | FileCheck %s --check-prefix=DIAG-SAFE
-# RUN: not %lld -lSystem -icf junk -o %t/junk %t/main.o 2>&1 \
+# RUN: not %lld -lSystem --icf=junk -o %t/junk %t/main.o 2>&1 \
 # RUN:     | FileCheck %s --check-prefix=DIAG-JUNK
-# RUN: not %lld -lSystem -icf all -no_deduplicate -o %t/clash %t/main.o 2>&1 \
+# RUN: not %lld -lSystem --icf=all -no_deduplicate -o %t/clash %t/main.o 2>&1 \
 # RUN:     | FileCheck %s --check-prefix=DIAG-CLASH
 
 # DIAG-EMPTY-NOT: {{.}}
-# DIAG-SAFE: `-icf safe' is not yet implemented, reverting to `none'
-# DIAG-JUNK: unknown -icf OPTION `junk', defaulting to `none'
-# DIAG-CLASH: `-icf all' conflicts with -no_deduplicate, setting to `none'
+# DIAG-SAFE: `--icf=safe' is not yet implemented, reverting to `none'
+# DIAG-JUNK: unknown --icf=OPTION `junk', defaulting to `none'
+# DIAG-CLASH: `--icf=all' conflicts with -no_deduplicate, setting to `none'
 
 # RUN: llvm-objdump -d --syms %t/all | FileCheck %s --check-prefix=FOLD
 # RUN: llvm-objdump -d --syms %t/none | FileCheck %s --check-prefix=NOOP
diff --git a/lld/test/MachO/icf-scale.s b/lld/test/MachO/icf-scale.s
--- a/lld/test/MachO/icf-scale.s
+++ b/lld/test/MachO/icf-scale.s
@@ -2,7 +2,7 @@
 # RUN: rm -rf %t*
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o
-# RUN: %lld -lSystem -icf all -o %t %t.o
+# RUN: %lld -lSystem --icf=all -o %t %t.o
 # RUN: llvm-objdump -d --syms %t | FileCheck %s
 
 ## When ICF has fewer than 1 Ki functions to segregate into equivalence classes,
diff --git a/lld/test/MachO/icf.s b/lld/test/MachO/icf.s
--- a/lld/test/MachO/icf.s
+++ b/lld/test/MachO/icf.s
@@ -2,7 +2,7 @@
 # RUN: rm -rf %t; mkdir %t
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t/main.o
-# RUN: %lld -lSystem -icf all -o %t/main %t/main.o
+# RUN: %lld -lSystem --icf=all -o %t/main %t/main.o
 # RUN: llvm-objdump -d --syms %t/main | FileCheck %s
 
 # CHECK-LABEL: SYMBOL TABLE: