Fix misspelled instruction in X86 assembly parser

[epastor]

Summary

Did not correctly handle "jecxz short <address>".

Discovered while working on LLVM-ML; shows up in z_Windows_NT-586_asm.asm from the OpenMP runtime

[RKSimon]

test case?

[MaskRay]

More concretely, branch instruction tests in llvm/test/MC/X86/x86-32.s can be moved outside, then you can add a test for jecxz. jexcz seems untested.

[epastor]

Add test case

[epastor]

In D104194#2815762, @MaskRay wrote:

More concretely, branch instruction tests in llvm/test/MC/X86/x86-32.s can be moved outside, then you can add a test for jecxz. jexcz seems untested.

Thanks for the concrete feedback! I couldn't figure out where the tests for this were. It looks like the "jcc short" family is all tested in intel-syntax.s, so I've added it there.

[MaskRay]

Looks great!

llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp

if (Name.consume_back(".d32")) {
     ForcedDispEncoding = DispEncoding_Disp8;
   }
 
   StringRef PatchedName = Name;
 
   // Hack to skip "short" following Jcc.
   if (isParsingIntelSyntax() &&
       (PatchedName == "jmp" || PatchedName == "jc" || PatchedName == "jnc" ||
-       PatchedName == "jcxz" || PatchedName == "jexcz" ||
+       PatchedName == "jcxz" || PatchedName == "jecxz" ||
        (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.
       Parser.Lex();

llvm/test/MC/X86/intel-syntax.s

 // CHECK: lcalll *(%rax)
   lcall [rax]
 // CHECK: ljmpl *(%rax)
   jmp FWORD ptr [rax]
 // CHECK: ljmpq *(%rax)
   ljmp [rax]
 // CHECK: jmp _foo
   jmp short _foo
+// CHECK: jb _foo
+  jc short _foo
+// CHECK: jae _foo
+  jnc short _foo
+// CHECK: jecxz _foo
+  jecxz short _foo
 // CHECK: jp _foo
   jpe short _foo
 
 // CHECK: movl  $257, -4(%rsp)
   mov DWORD PTR [RSP - 4], 257
 // CHECK: movl  $258, 4(%rsp)
   mov DWORD PTR [RSP + 4], 258
 // CHECK: movq  $123, -16(%rsp)