diff --git a/lib/rubygems/platform.rb b/lib/rubygems/platform.rb
index 6d328740d5..67302dc85d 100644
--- a/lib/rubygems/platform.rb
+++ b/lib/rubygems/platform.rb
@@ -88,18 +88,7 @@ class Gem::Platform
     when Array then
       @cpu, @os, @version = arch
     when String then
-      arch_str = arch
-      arch = arch.split "-"
-
-      if arch.length > 2 && !arch.last.match?(/^\d+(\.\d+)?$/) # reassemble x86-linux-{libc}
-        extra = arch.pop
-        arch.last << "-#{extra}"
-      end
-
-      cpu = arch.shift
-      if cpu.nil? || cpu == ""
-        raise ArgumentError, "empty cpu in platform #{arch_str.inspect}"
-      end
+      cpu, os = arch.sub(/-+$/, "").split("-", 2)
 
       @cpu = if cpu.match?(/i\d86/)
         "x86"
@@ -107,43 +96,37 @@ class Gem::Platform
         cpu
       end
 
-      if arch.length == 2 && arch.last.match?(/^\d+(\.\d+)?$/) # for command-line
-        @os, @version = arch
-        return
-      end
-
-      # discard the version element, it didn't match the version pattern (\d+(\.\d+)?)
-      os, = arch
       if os.nil?
         @cpu = nil
         os = cpu
       end # legacy jruby
 
       @os, @version = case os
-                      when /aix(\d+)?/ then             ["aix",       $1]
-                      when /cygwin/ then                ["cygwin",    nil]
-                      when /darwin(\d+)?/ then          ["darwin",    $1]
-                      when /^macruby$/ then             ["macruby",   nil]
-                      when /freebsd(\d+)?/ then         ["freebsd",   $1]
-                      when /^java$/, /^jruby$/ then     ["java",      nil]
-                      when /^java(\d+(?:\.\d+)*)?/ then ["java", $1]
-                      when /^dalvik(\d+)?$/ then        ["dalvik",    $1]
-                      when /^dotnet$/ then              ["dotnet",    nil]
-                      when /^dotnet(\d+(?:\.\d+)*)?/ then ["dotnet", $1]
-                      when /linux-?(\w+)?/ then         ["linux",     $1]
-                      when /mingw32/ then               ["mingw32",   nil]
-                      when /mingw-?(\w+)?/ then         ["mingw",     $1]
-                      when /(mswin\d+)(?:\_(\d+))?/ then
+                      when /aix-?(\d+)?/ then                ["aix",     $1]
+                      when /cygwin/ then                     ["cygwin",  nil]
+                      when /darwin-?(\d+)?/ then             ["darwin",  $1]
+                      when "macruby" then                    ["macruby", nil]
+                      when /^macruby-?(\d+(?:\.\d+)*)?/ then ["macruby", $1]
+                      when /freebsd-?(\d+)?/ then            ["freebsd", $1]
+                      when "java", "jruby" then              ["java",    nil]
+                      when /^java-?(\d+(?:\.\d+)*)?/ then    ["java",    $1]
+                      when /^dalvik-?(\d+)?$/ then           ["dalvik",  $1]
+                      when /^dotnet$/ then                   ["dotnet",  nil]
+                      when /^dotnet-?(\d+(?:\.\d+)*)?/ then  ["dotnet",  $1]
+                      when /linux-?(\w+)?/ then              ["linux",   $1]
+                      when /mingw32/ then                    ["mingw32", nil]
+                      when /mingw-?(\w+)?/ then              ["mingw",   $1]
+                      when /(mswin\d+)(?:[_-](\d+))?/ then
                         os = $1
                         version = $2
                         @cpu = "x86" if @cpu.nil? && os.end_with?("32")
                         [os, version]
-                      when /netbsdelf/ then             ["netbsdelf", nil]
-                      when /openbsd(\d+\.\d+)?/ then    ["openbsd",   $1]
-                      when /solaris(\d+\.\d+)?/ then    ["solaris",   $1]
-                      when /wasi/ then                  ["wasi",      nil]
+                      when /netbsdelf/ then                  ["netbsdelf", nil]
+                      when /openbsd-?(\d+\.\d+)?/ then       ["openbsd",   $1]
+                      when /solaris-?(\d+\.\d+)?/ then       ["solaris",   $1]
+                      when /wasi/ then                       ["wasi",      nil]
                       # test
-                      when /^(\w+_platform)(\d+)?/ then [$1,          $2]
+                      when /^(\w+_platform)(\d+)?/ then      [$1,          $2]
                       else ["unknown", nil]
       end
     when Gem::Platform then
@@ -160,10 +143,7 @@ class Gem::Platform
   end
 
   def to_s
-    if @cpu.nil? && @os && @version
-      return "#{@os}#{@version}"
-    end
-    to_a.compact.join "-"
+    to_a.compact.join(@cpu.nil? ? "" : "-")
   end
 
   ##
diff --git a/test/rubygems/test_gem_platform.rb b/test/rubygems/test_gem_platform.rb
index a0a961284f..455ee45c3f 100644
--- a/test/rubygems/test_gem_platform.rb
+++ b/test/rubygems/test_gem_platform.rb
@@ -158,6 +158,10 @@ class TestGemPlatform < Gem::TestCase
       "darwin0---" => [nil, "darwin", "0"],
       "x86-linux-x8611.0l" => ["x86", "linux", "x8611"],
       "0-x86linuxx86---" => ["0", "linux", "x86"],
+      "x86_64-macruby-x86" => ["x86_64", "macruby", nil],
+      "x86_64-dotnetx86" => ["x86_64", "dotnet", nil],
+      "x86_64-dalvik0" => ["x86_64", "dalvik", "0"],
+      "x86_64-dotnet1." => ["x86_64", "dotnet", "1"],
     }
 
     test_cases.each do |arch, expected|