diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -5734,13 +5734,14 @@
   }
 
   // If we have a '#', it's an immediate offset, else assume it's a register
-  // offset. Be friendly and also accept a plain integer (without a leading
-  // hash) for gas compatibility.
+  // offset. Be friendly and also accept a plain integer or expression (without
+  // a leading hash) for gas compatibility.
   if (Parser.getTok().is(AsmToken::Hash) ||
       Parser.getTok().is(AsmToken::Dollar) ||
+      Parser.getTok().is(AsmToken::LParen) ||
       Parser.getTok().is(AsmToken::Integer)) {
-    if (Parser.getTok().isNot(AsmToken::Integer))
-      Parser.Lex(); // Eat '#' or '$'.
+    if (Parser.getTok().isNot(AsmToken::Integer) && Parser.getTok().isNot(AsmToken::LParen))
+        Parser.Lex(); // Eat '#' or '$'
     E = Parser.getTok().getLoc();
 
     bool isNegative = getParser().getTok().is(AsmToken::Minus);
diff --git a/llvm/test/MC/ARM/gas-compl-mem-offset-paren.s b/llvm/test/MC/ARM/gas-compl-mem-offset-paren.s
new file mode 100644
--- /dev/null
+++ b/llvm/test/MC/ARM/gas-compl-mem-offset-paren.s
@@ -0,0 +1,26 @@
+@ RUN: llvm-mc -triple=arm < %s | FileCheck %s
+
+.syntax unified
+
+@ CHECK: ldr	r12, [sp, #15]
+ldr r12, [sp, (15)]
+
+@ CHECK: ldr	r12, [sp, #15]
+ldr r12, [sp, #(15)]
+
+@ CHECK: ldr	r12, [sp, #15]
+.syntax unified
+ldr r12, [sp, $(15)]
+
+@ CHECK: ldr	r12, [sp, #100]
+.syntax unified
+ldr r12, [sp, (((15+5)*5))]
+
+@ CHECK: ldr	r12, [sp, #100]
+.syntax unified
+ldr r12, [sp, #(((15+5)*5))]
+
+
+@ CHECK: ldr	r12, [sp, #100]
+.syntax unified
+ldr r12, [sp, $(((15+5)*5))]