[X86] Print %st(0) as %st when its implicit to the instruction. Continue printing it as %st(0) when its encoded in the instruction.

This is a step back from the change I made in r352985. This appears to be more consistent with gcc and objdump behavior.

llvm-svn: 353015

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/InstPrinter/X86IntelInstPrinter.cpp b/llvm/lib/Target/X86/InstPrinter/X86IntelInstPrinter.cpp
index 0cbd2ecd99f..9015aa14768 100644
--- a/llvm/lib/Target/X86/InstPrinter/X86IntelInstPrinter.cpp
+++ b/llvm/lib/Target/X86/InstPrinter/X86IntelInstPrinter.cpp
@@ -159,3 +159,14 @@ void X86IntelInstPrinter::printU8Imm(const MCInst *MI, unsigned Op,
 
   O << formatImm(MI->getOperand(Op).getImm() & 0xff);
 }
+
+void X86IntelInstPrinter::printSTiRegOperand(const MCInst *MI, unsigned OpNo,
+                                            raw_ostream &OS) {
+  const MCOperand &Op = MI->getOperand(OpNo);
+  unsigned Reg = Op.getReg();
+  // Override the default printing to print st(0) instead st.
+  if (Reg == X86::ST0)
+    OS << "st(0)";
+  else
+    printRegName(OS, Reg);
+}