From a951f77ca31b43551bd41765504519d6d76e6cbf Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Thu, 19 Jan 2012 18:40:55 +0000
Subject: [PATCH] Post process 'and', 'sub' instructions and select better
 encoding, if available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148489 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/AsmParser/X86AsmParser.cpp | 78 +++++++++++++++++++++++
 test/MC/X86/intel-syntax-encoding.s       |  8 +++
 2 files changed, 86 insertions(+)

diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 1763419408d..67c4a647e55 100644
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -1331,6 +1331,84 @@ processInstruction(MCInst &Inst,
     Inst = TmpInst;
     return true;
   }
+  case X86::ADD16i16: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti16i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::ADD16ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::AX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::AX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::ADD32i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti32i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::ADD32ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::EAX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::EAX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::ADD64i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti64i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::ADD64ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::RAX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::RAX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::SUB16i16: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti16i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::SUB16ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::AX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::AX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::SUB32i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti32i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::SUB32ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::EAX));
+    TmpInst.addOperand(MCOperand::CreateReg(X86::EAX));
+    TmpInst.addOperand(Inst.getOperand(0));
+    Inst = TmpInst;
+    return true;
+  }
+  case X86::SUB64i32: {
+    if (!Inst.getOperand(0).isImm() ||
+        !isImmSExti64i8Value(Inst.getOperand(0).getImm()))
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::SUB64ri8);
+    TmpInst.addOperand(MCOperand::CreateReg(X86::RAX));
+    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
index 23eff016910..c81636bcbbd 100644
--- a/test/MC/X86/intel-syntax-encoding.s
+++ b/test/MC/X86/intel-syntax-encoding.s
@@ -24,3 +24,11 @@
 // CHECK: encoding: [0x48,0x89,0x44,0x24,0xf0]	
 	mov	QWORD PTR [RSP - 16], RAX
 
+// CHECK: encoding: [0x66,0x83,0xc0,0xf4]
+	add	ax, -12
+// CHECK: encoding: [0x83,0xc0,0xf4]
+	add	eax, -12
+// CHECK: encoding: [0x48,0x83,0xc0,0xf4]
+	add	rax, -12
+
+
-- 
2.34.1