1 files changed, 34 insertions, 5 deletions

diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 2ab979a7b76..6239cfc3cdf 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -848,6 +848,8 @@ private:
                                               const SMLoc &StartLoc,
                                               SMLoc &EndLoc);
 
+  X86::CondCode ParseConditionCode(StringRef CCode);
+
   bool ParseIntelMemoryOperandSize(unsigned &Size);
   std::unique_ptr<X86Operand>
   CreateMemForInlineAsm(unsigned SegReg, const MCExpr *Disp, unsigned BaseReg,
@@ -2005,6 +2007,29 @@ std::unique_ptr<X86Operand> X86AsmParser::ParseATTOperand() {
   }
 }
 
+// X86::COND_INVALID if not a recognized condition code or alternate mnemonic,
+// otherwise the EFLAGS Condition Code enumerator.
+X86::CondCode X86AsmParser::ParseConditionCode(StringRef CC) {
+  return StringSwitch<X86::CondCode>(CC)
+      .Case("o", X86::COND_O)          // Overflow
+      .Case("no", X86::COND_NO)        // No Overflow
+      .Cases("b", "nae", X86::COND_B)  // Below/Neither Above nor Equal
+      .Cases("ae", "nb", X86::COND_AE) // Above or Equal/Not Below
+      .Cases("e", "z", X86::COND_E)    // Equal/Zero
+      .Cases("ne", "nz", X86::COND_NE) // Not Equal/Not Zero
+      .Cases("be", "na", X86::COND_BE) // Below or Equal/Not Above
+      .Cases("a", "nbe", X86::COND_A)  // Above/Neither Below nor Equal
+      .Case("s", X86::COND_S)          // Sign
+      .Case("ns", X86::COND_NS)        // No Sign
+      .Cases("p", "pe", X86::COND_P)   // Parity/Parity Even
+      .Cases("np", "po", X86::COND_NP) // No Parity/Parity Odd
+      .Cases("l", "nge", X86::COND_L)  // Less/Neither Greater nor Equal
+      .Cases("ge", "nl", X86::COND_GE) // Greater or Equal/Not Less
+      .Cases("le", "ng", X86::COND_LE) // Less or Equal/Not Greater
+      .Cases("g", "nle", X86::COND_G)  // Greater/Neither Less nor Equal
+      .Default(X86::COND_INVALID);
+}
+
 // true on failure, false otherwise
 // If no {z} mark was found - Parser doesn't advance
 bool X86AsmParser::ParseZ(std::unique_ptr<X86Operand> &Z,
@@ -2354,16 +2379,20 @@ bool X86AsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
 
   StringRef PatchedName = Name;
 
-  if ((Name.equals("jmp") || Name.equals("jc") || Name.equals("jz")) &&
-      isParsingIntelSyntax() && isParsingInlineAsm()) {
+  // Hack to skip "short" following Jcc.
+  if (isParsingIntelSyntax() &&
+      (PatchedName == "jmp" ||
+       (PatchedName.startswith("j") &&
+        ParseConditionCode(PatchedName.substr(1)) != X86::COND_INVALID))) {
     StringRef NextTok = Parser.getTok().getString();
     if (NextTok == "short") {
       SMLoc NameEndLoc =
           NameLoc.getFromPointer(NameLoc.getPointer() + Name.size());
-      // Eat the short keyword
+      // Eat the short keyword.
       Parser.Lex();
-      // MS ignores the short keyword, it determines the jmp type based
-      // on the distance of the label
+      // MS and GAS ignore the short keyword; they both determine the jmp type
+      // based on the distance of the label. (NASM does emit different code with
+      // and without "short," though.)
       InstInfo->AsmRewrites->emplace_back(AOK_Skip, NameEndLoc,
                                           NextTok.size() + 1);
     }