From ac0f0486022fb1798579c9a550154e839770efa9 Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Thu, 19 Jan 2012 17:53:25 +0000
Subject: [PATCH] Post process 'xor', 'or' and 'cmp' instructions and select
 better encoding, if available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148485 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/AsmParser/X86AsmParser.cpp | 114 ++++++++++++++++++++++
 test/MC/X86/intel-syntax-encoding.s       |  22 +++++
 2 files changed, 136 insertions(+)
 create mode 100644 test/MC/X86/intel-syntax-encoding.s

diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index cef0b169158..5fc38d39d91 100644
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -1217,6 +1217,120 @@ processInstruction(MCInst &Inst,
     Inst = TmpInst;
     return true;
   }
+  case X86::XOR16i16: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti16i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::XOR16ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::AX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::AX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::XOR32i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti32i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::XOR32ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::EAX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::EAX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::XOR64i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti64i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::XOR64ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::RAX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::RAX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::OR16i16: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti16i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::OR16ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::AX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::AX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::OR32i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti32i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::OR32ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::EAX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::EAX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::OR64i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti64i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::OR64ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::RAX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::RAX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::CMP16i16: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti16i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::CMP16ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::AX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::CMP32i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti32i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::CMP32ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::EAX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::CMP64i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti64i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::CMP64ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::RAX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
   }
   return false;
 }
diff --git a/test/MC/X86/intel-syntax-encoding.s b/test/MC/X86/intel-syntax-encoding.s
new file mode 100644
index 00000000000..0d1b2fa9932
--- /dev/null
+++ b/test/MC/X86/intel-syntax-encoding.s
@@ -0,0 +1,22 @@
+// RUN: llvm-mc -x86-asm-syntax=intel -triple x86_64-unknown-unknown --show-encoding %s | FileCheck %s
+
+// CHECK: encoding: [0x66,0x83,0xf0,0x0c]
+	xor	ax, 12
+// CHECK: encoding: [0x83,0xf0,0x0c]
+	xor	eax, 12
+// CHECK: encoding: [0x48,0x83,0xf0,0x0c]
+	xor	rax, 12
+
+// CHECK: encoding: [0x66,0x83,0xc8,0x0c]
+	or	ax, 12
+// CHECK: encoding: [0x83,0xc8,0x0c]
+	or	eax, 12
+// CHECK: encoding: [0x48,0x83,0xc8,0x0c]
+	or	rax, 12
+
+// CHECK: encoding: [0x66,0x83,0xf8,0x0c]
+	cmp	ax, 12
+// CHECK: encoding: [0x83,0xf8,0x0c]
+	cmp	eax, 12
+// CHECK: encoding: [0x48,0x83,0xf8,0x0c]
+	cmp	rax, 12