diff --git a/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/pre-process.ll b/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/pre-process.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/pre-process.ll
@@ -0,0 +1,15 @@
+; Test that update_llc_test_checks.py can run pre-processing commands.
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s --check-prefix=CHECK-ADD
+; RUN: sed 's/add /sub /g' %s | llc -mtriple=x86_64-unknown-unknown \
+; RUN:   | FileCheck %s --check-prefix=CHECK-SUB
+; Check that multiple pre-processing commands are handled
+; RUN: sed 's/add /sub /g' %s | sed 's/i64 /i16 /g' | cat \
+; RUN:  | llc -mtriple=x86_64-unknown-unknown | FileCheck %s --check-prefix=CHECK-SUB-I16
+
+define i64 @test_add_constant(i64 %arg) nounwind {
+entry:
+  %a1 = add i64 %arg, 1
+  %a2 = add i64 %a1, 2
+  %a3 = add i64 %a2, 3
+  ret i64 %a3
+}
diff --git a/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/pre-process.ll.expected b/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/pre-process.ll.expected
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/pre-process.ll.expected
@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; Test that update_llc_test_checks.py can run pre-processing commands.
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s --check-prefix=CHECK-ADD
+; RUN: sed 's/add /sub /g' %s | llc -mtriple=x86_64-unknown-unknown \
+; RUN:   | FileCheck %s --check-prefix=CHECK-SUB
+; Check that multiple pre-processing commands are handled
+; RUN: sed 's/add /sub /g' %s | sed 's/i64 /i16 /g' | cat \
+; RUN:  | llc -mtriple=x86_64-unknown-unknown | FileCheck %s --check-prefix=CHECK-SUB-I16
+
+define i64 @test_add_constant(i64 %arg) nounwind {
+; CHECK-ADD-LABEL: test_add_constant:
+; CHECK-ADD:       # %bb.0: # %entry
+; CHECK-ADD-NEXT:    leaq 6(%rdi), %rax
+; CHECK-ADD-NEXT:    retq
+;
+; CHECK-SUB-LABEL: test_add_constant:
+; CHECK-SUB:       # %bb.0: # %entry
+; CHECK-SUB-NEXT:    leaq -6(%rdi), %rax
+; CHECK-SUB-NEXT:    retq
+;
+; CHECK-SUB-I16-LABEL: test_add_constant:
+; CHECK-SUB-I16:       # %bb.0: # %entry
+; CHECK-SUB-I16-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-SUB-I16-NEXT:    leal -6(%rdi), %eax
+; CHECK-SUB-I16-NEXT:    # kill: def $ax killed $ax killed $eax
+; CHECK-SUB-I16-NEXT:    retq
+entry:
+  %a1 = add i64 %arg, 1
+  %a2 = add i64 %a1, 2
+  %a3 = add i64 %a2, 3
+  ret i64 %a3
+}
diff --git a/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/pre-process.test b/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/pre-process.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/pre-process.test
@@ -0,0 +1,10 @@
+# REQUIRES: x86-registered-target
+## Test that update_llc_test_checks.py can run pre-processing commands.
+
+## Test that update_test_checks.py can run pre-processing commands.
+# RUN: cp -f %S/Inputs/pre-process.ll %t.ll && %update_llc_test_checks %t.ll
+# RUN: diff -u %t.ll %S/Inputs/pre-process.ll.expected
+## Check that running the script again does not change the result:
+# RUN: %update_llc_test_checks %t.ll
+# RUN: diff -u %t.ll %S/Inputs/pre-process.ll.expected
+
diff --git a/llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/pre-process.ll b/llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/pre-process.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/pre-process.ll
@@ -0,0 +1,18 @@
+; Test that update_test_checks.py can run pre-processing commands.
+; RUN: opt < %s -instsimplify -S | FileCheck %s --check-prefix=CHECK-AS200
+; RUN: sed -e 's/addrspace(200)/addrspace(0)/g' -e 's/-A200-P200-G200//g' %s \
+; RUN:   | opt -instsimplify -S | FileCheck %s --check-prefix=CHECK-AS0
+; Check that multiple pre-processing commands are handled
+; RUN: sed 's/addrspace(200)/addrspace(1)/g' %s | sed 's/-A1-P1-G1//g' \
+; RUN:   | opt -instsimplify -S | FileCheck %s --check-prefix=CHECK-AS1
+; More than two commands should also be fine
+; RUN: cat %s | cat | cat | cat | opt < %s -instsimplify -S \
+; RUN:   | FileCheck %s --check-prefix=CHECK-AS200-NOOP-PRE-PROCESS
+
+target datalayout = "e-m:e-p200:128:128:128:64-p:64:64-A200-P200-G200"
+
+define i8 addrspace(200)* @test_zerogep_in_different_as(i8 addrspace(200)* %arg) addrspace(200) nounwind {
+entry:
+  %ret = getelementptr inbounds i8, i8 addrspace(200)* %arg, i64 0
+  ret i8 addrspace(200)* %ret
+}
diff --git a/llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/pre-process.ll.expected b/llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/pre-process.ll.expected
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/pre-process.ll.expected
@@ -0,0 +1,39 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --function-signature
+; Test that update_test_checks.py can run pre-processing commands.
+; RUN: opt < %s -instsimplify -S | FileCheck %s --check-prefix=CHECK-AS200
+; RUN: sed -e 's/addrspace(200)/addrspace(0)/g' -e 's/-A200-P200-G200//g' %s \
+; RUN:   | opt -instsimplify -S | FileCheck %s --check-prefix=CHECK-AS0
+; Check that multiple pre-processing commands are handled
+; RUN: sed 's/addrspace(200)/addrspace(1)/g' %s | sed 's/-A1-P1-G1//g' \
+; RUN:   | opt -instsimplify -S | FileCheck %s --check-prefix=CHECK-AS1
+; More than two commands should also be fine
+; RUN: cat %s | cat | cat | cat | opt < %s -instsimplify -S \
+; RUN:   | FileCheck %s --check-prefix=CHECK-AS200-NOOP-PRE-PROCESS
+
+target datalayout = "e-m:e-p200:128:128:128:64-p:64:64-A200-P200-G200"
+
+define i8 addrspace(200)* @test_zerogep_in_different_as(i8 addrspace(200)* %arg) addrspace(200) nounwind {
+; CHECK-AS200-LABEL: define {{[^@]+}}@test_zerogep_in_different_as
+; CHECK-AS200-SAME: (i8 addrspace(200)* [[ARG:%.*]]) addrspace(200) #[[ATTR0:[0-9]+]] {
+; CHECK-AS200-NEXT:  entry:
+; CHECK-AS200-NEXT:    ret i8 addrspace(200)* [[ARG]]
+;
+; CHECK-AS0-LABEL: define {{[^@]+}}@test_zerogep_in_different_as
+; CHECK-AS0-SAME: (i8* [[ARG:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-AS0-NEXT:  entry:
+; CHECK-AS0-NEXT:    ret i8* [[ARG]]
+;
+; CHECK-AS1-LABEL: define {{[^@]+}}@test_zerogep_in_different_as
+; CHECK-AS1-SAME: (i8 addrspace(1)* [[ARG:%.*]]) addrspace(1) #[[ATTR0:[0-9]+]] {
+; CHECK-AS1-NEXT:  entry:
+; CHECK-AS1-NEXT:    ret i8 addrspace(1)* [[ARG]]
+;
+; CHECK-AS200-NOOP-PRE-PROCESS-LABEL: define {{[^@]+}}@test_zerogep_in_different_as
+; CHECK-AS200-NOOP-PRE-PROCESS-SAME: (i8 addrspace(200)* [[ARG:%.*]]) addrspace(200) #[[ATTR0:[0-9]+]] {
+; CHECK-AS200-NOOP-PRE-PROCESS-NEXT:  entry:
+; CHECK-AS200-NOOP-PRE-PROCESS-NEXT:    ret i8 addrspace(200)* [[ARG]]
+;
+entry:
+  %ret = getelementptr inbounds i8, i8 addrspace(200)* %arg, i64 0
+  ret i8 addrspace(200)* %ret
+}
diff --git a/llvm/test/tools/UpdateTestChecks/update_test_checks/pre-process.test b/llvm/test/tools/UpdateTestChecks/update_test_checks/pre-process.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/UpdateTestChecks/update_test_checks/pre-process.test
@@ -0,0 +1,6 @@
+## Test that update_test_checks.py can run pre-processing commands.
+# RUN: cp -f %S/Inputs/pre-process.ll %t.ll && %update_test_checks --function-signature %t.ll
+# RUN: diff -u %t.ll %S/Inputs/pre-process.ll.expected
+## Check that running the script again does not change the result:
+# RUN: %update_test_checks %t.ll
+# RUN: diff -u %t.ll %S/Inputs/pre-process.ll.expected
diff --git a/llvm/utils/UpdateTestChecks/common.py b/llvm/utils/UpdateTestChecks/common.py
--- a/llvm/utils/UpdateTestChecks/common.py
+++ b/llvm/utils/UpdateTestChecks/common.py
@@ -2,6 +2,7 @@
 
 import copy
 import glob
+import os
 import re
 import subprocess
 import sys
@@ -141,11 +142,23 @@
   return True
 
 # Invoke the tool that is being tested.
-def invoke_tool(exe, cmd_args, ir):
+def invoke_tool(exe, cmd_args, ir, preprocess_cmd=None, verbose=False):
   with open(ir) as ir_file:
     # TODO Remove the str form which is used by update_test_checks.py and
     # update_llc_test_checks.py
     # The safer list form is used by update_cc_test_checks.py
+    if preprocess_cmd:
+      # Allow pre-processing the IR file (e.g. using sed):
+      assert isinstance(preprocess_cmd, str)  # TODO: use a list instead of using shell
+      preprocess_cmd = preprocess_cmd.replace('%s', ir).strip()
+      if verbose:
+        print('Pre-processing input file: ', ir, " with command '",
+              preprocess_cmd, "'", sep="", file=sys.stderr)
+      # Python 2.7 doesn't have subprocess.DEVNULL:
+      with open(os.devnull, 'w') as devnull:
+        pp = subprocess.Popen(preprocess_cmd, shell=True, stdin=devnull,
+                              stdout=subprocess.PIPE)
+        ir_file = pp.stdout
     if isinstance(cmd_args, list):
       stdout = subprocess.check_output([exe] + cmd_args, stdin=ir_file)
     else:
diff --git a/llvm/utils/update_llc_test_checks.py b/llvm/utils/update_llc_test_checks.py
--- a/llvm/utils/update_llc_test_checks.py
+++ b/llvm/utils/update_llc_test_checks.py
@@ -60,8 +60,13 @@
         common.warn('Skipping unparseable RUN line: ' + l)
         continue
 
-      commands = [cmd.strip() for cmd in l.split('|', 1)]
-      llc_cmd = commands[0]
+      commands = [cmd.strip() for cmd in l.split('|')]
+      assert len(commands) >= 2
+      preprocess_cmd = None
+      if len(commands) > 2:
+        preprocess_cmd = " | ".join(commands[:-2])
+      llc_cmd = commands[-2]
+      filecheck_cmd = commands[-1]
       llc_tool = llc_cmd.split(' ')[0]
 
       triple_in_cmd = None
@@ -74,9 +79,6 @@
       if m:
         march_in_cmd = m.groups()[0]
 
-      filecheck_cmd = ''
-      if len(commands) > 1:
-        filecheck_cmd = commands[1]
       common.verify_filecheck_prefixes(filecheck_cmd)
       if llc_tool not in LLC_LIKE_TOOLS:
         common.warn('Skipping non-llc RUN line: ' + l)
@@ -97,7 +99,8 @@
 
       # FIXME: We should use multiple check prefixes to common check lines. For
       # now, we just ignore all but the last.
-      run_list.append((check_prefixes, llc_cmd_args, triple_in_cmd, march_in_cmd))
+      run_list.append((check_prefixes, llc_tool, llc_cmd_args, preprocess_cmd,
+                       triple_in_cmd, march_in_cmd))
 
     if ti.path.endswith('.mir'):
       check_indent = '  '
@@ -113,12 +116,13 @@
             'replace_function_regex': []}),
         scrubber_args=[ti.args])
 
-    for prefixes, llc_args, triple_in_cmd, march_in_cmd in run_list:
+    for prefixes, llc_tool, llc_args, preprocess_cmd, triple_in_cmd, march_in_cmd in run_list:
       common.debug('Extracted LLC cmd:', llc_tool, llc_args)
       common.debug('Extracted FileCheck prefixes:', str(prefixes))
 
       raw_tool_output = common.invoke_tool(ti.args.llc_binary or llc_tool,
-                                           llc_args, ti.path)
+                                           llc_args, ti.path, preprocess_cmd,
+                                           verbose=ti.args.verbose)
       triple = triple_in_cmd or triple_in_ir
       if not triple:
         triple = asm.get_triple_from_march(march_in_cmd)
diff --git a/llvm/utils/update_test_checks.py b/llvm/utils/update_test_checks.py
--- a/llvm/utils/update_test_checks.py
+++ b/llvm/utils/update_test_checks.py
@@ -80,7 +80,13 @@
         common.warn('Skipping unparseable RUN line: ' + l)
         continue
 
-      (tool_cmd, filecheck_cmd) = tuple([cmd.strip() for cmd in l.split('|', 1)])
+      commands = [cmd.strip() for cmd in l.split('|')]
+      assert len(commands) >= 2
+      preprocess_cmd = None
+      if len(commands) > 2:
+        preprocess_cmd = " | ".join(commands[:-2])
+      tool_cmd = commands[-2]
+      filecheck_cmd = commands[-1]
       common.verify_filecheck_prefixes(filecheck_cmd)
       if not tool_cmd.startswith(opt_basename + ' '):
         common.warn('Skipping non-%s RUN line: %s' % (opt_basename, l))
@@ -101,7 +107,7 @@
 
       # FIXME: We should use multiple check prefixes to common check lines. For
       # now, we just ignore all but the last.
-      prefix_list.append((check_prefixes, tool_cmd_args))
+      prefix_list.append((check_prefixes, tool_cmd_args, preprocess_cmd))
 
     global_vars_seen_dict = {}
     builder = common.FunctionTestBuilder(
@@ -109,12 +115,13 @@
       flags=ti.args,
       scrubber_args=[])
 
-    for prefixes, opt_args in prefix_list:
+    for prefixes, opt_args, preprocess_cmd in prefix_list:
       common.debug('Extracted opt cmd: ' + opt_basename + ' ' + opt_args)
       common.debug('Extracted FileCheck prefixes: ' + str(prefixes))
 
       raw_tool_output = common.invoke_tool(ti.args.opt_binary, opt_args,
-                                           ti.path)
+                                           ti.path, preprocess_cmd=preprocess_cmd,
+                                           verbose=ti.args.verbose)
       builder.process_run_line(common.OPT_FUNCTION_RE, common.scrub_body,
               raw_tool_output, prefixes)
 
@@ -122,7 +129,7 @@
     is_in_function = False
     is_in_function_start = False
     has_checked_pre_function_globals = False
-    prefix_set = set([prefix for prefixes, _ in prefix_list for prefix in prefixes])
+    prefix_set = set([prefix for prefixes, _, _ in prefix_list for prefix in prefixes])
     common.debug('Rewriting FileCheck prefixes:', str(prefix_set))
     output_lines = []