diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 1f045ac1711f..36075227b710 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -783,8 +783,13 @@ bool AsmParser::ParseStatement() {
     return false;
   }
 
+  // Canonicalize the opcode to lower case.
+  SmallString<128> Opcode;
+  for (unsigned i = 0, e = IDVal.size(); i != e; ++i)
+    Opcode.push_back(tolower(IDVal[i]));
+  
   SmallVector<MCParsedAsmOperand*, 8> ParsedOperands;
-  bool HadError = getTargetParser().ParseInstruction(IDVal, IDLoc,
+  bool HadError = getTargetParser().ParseInstruction(Opcode.str(), IDLoc,
                                                      ParsedOperands);
   if (!HadError && Lexer.isNot(AsmToken::EndOfStatement))
     HadError = TokError("unexpected token in argument list");
diff --git a/llvm/test/MC/AsmParser/X86/x86_instructions.s b/llvm/test/MC/AsmParser/X86/x86_instructions.s
index 16a80460e809..4bc8a4bb3a84 100644
--- a/llvm/test/MC/AsmParser/X86/x86_instructions.s
+++ b/llvm/test/MC/AsmParser/X86/x86_instructions.s
@@ -146,3 +146,8 @@ fadd %st(7)
 
 // CHECK: leal 0, %eax
         leal 0, %eax
+
+// rdar://7986634 - Insensitivity on opcodes.
+// CHECK: int3
+INT3
+