Index: lib/MC/MCParser/AsmParser.cpp
===================================================================
--- lib/MC/MCParser/AsmParser.cpp
+++ lib/MC/MCParser/AsmParser.cpp
@@ -2039,7 +2039,6 @@
   case AsmToken::AmpAmp:
   case AsmToken::Exclaim:
   case AsmToken::ExclaimEqual:
-  case AsmToken::Percent:
   case AsmToken::Less:
   case AsmToken::LessEqual:
   case AsmToken::LessLess:
@@ -2083,15 +2082,22 @@
   // Darwin doesn't use spaces to delmit arguments.
   AsmLexerSkipSpaceRAII ScopedSkipSpace(Lexer, IsDarwin);
 
+  bool SpaceEaten;
+
   for (;;) {
+    SpaceEaten = false;
     if (Lexer.is(AsmToken::Eof) || Lexer.is(AsmToken::Equal))
       return TokError("unexpected token in macro instantiation");
 
-    if (ParenLevel == 0 && Lexer.is(AsmToken::Comma))
-      break;
+    if (ParenLevel == 0) {
+
+      if (Lexer.is(AsmToken::Comma))
+        break;
 
-    if (Lexer.is(AsmToken::Space)) {
-      Lex(); // Eat spaces
+      if (Lexer.is(AsmToken::Space)) {
+        SpaceEaten = true;
+        Lex(); // Eat spaces
+      }
 
       // Spaces can delimit parameters, but could also be part an expression.
       // If the token after a space is an operator, add the token and the next
@@ -2101,14 +2107,12 @@
           // Check to see whether the token is used as an operator,
           // or part of an identifier
           const char *NextChar = getTok().getEndLoc().getPointer();
-          if (*NextChar == ' ')
+          if (*NextChar == ' ' || isdigit(*NextChar))
             AddTokens = 2;
         }
-
-        if (!AddTokens && ParenLevel == 0) {
-          break;
-        }
       }
+      if (AddTokens == 0 && SpaceEaten)
+        break;
     }
 
     // handleMacroEntry relies on not advancing the lexer here
Index: test/MC/AsmParser/macros-gas.s
===================================================================
--- test/MC/AsmParser/macros-gas.s
+++ test/MC/AsmParser/macros-gas.s
@@ -39,10 +39,10 @@
 .ascii "\_a \_b \_c"
 .endm
 
-// CHECK: .ascii "1 (23) "
+// CHECK: .ascii "1 (2 3) "
 test3_prime 1, (2 3)
 
-// CHECK: .ascii "1 (23) "
+// CHECK: .ascii "1 (2 3) "
 test3_prime 1 (2 3)
 
 // CHECK: .ascii "1 2 "
Index: test/MC/Mips/macro-sdc1.s
===================================================================
--- /dev/null
+++ test/MC/Mips/macro-sdc1.s
@@ -0,0 +1,22 @@
+# RUN: llvm-mc %s -triple=mipsel-unknown-linux -show-encoding -mcpu=mips32r2 | \
+# RUN:   FileCheck %s
+# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r2 | \
+# RUN:   FileCheck %s
+
+# Check that the IAS expands macro instructions in the same way as GAS.
+
+  .macro  EX insn, reg, src
+.ex\@: \insn \reg, \src
+  .endm
+
+  EX sdc1 $f0, 272+8($a0)
+# CHECK: sdc1    $f0, 280($4)
+
+  EX sdc1 $f0, 272 +8($a0)
+# CHECK: sdc1    $f0, 280($4)
+
+  EX sdc1 $f0, 272+ 8($a0)
+# CHECK: sdc1    $f0, 280($4)
+
+  EX sdc1 $f0, 272 + 8($a0)
+# CHECK: sdc1    $f0, 280($4)