From 776673ea09ad292dd8acd75e5e25363eed0b6220 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Sun, 11 Jan 2015 04:39:24 +0000
Subject: [PATCH] X86: teach X86TargetLowering about L,M,O constraints

Teach the ISelLowering for X86 about the L,M,O target specific constraints.
Although, for the moment, clang performs constraint validation and prevents
passing along inline asm which may have immediate constant constraints violated,
the backend should be able to cope with the invalid inline asm a bit better.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225596 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp            | 25 ++++++++++++++
 test/CodeGen/X86/x86-inline-asm-validation.ll | 34 +++++++++++++++++++
 2 files changed, 59 insertions(+)
 create mode 100644 test/CodeGen/X86/x86-inline-asm-validation.ll

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 927ff2c8101..9525ed0a220 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -26255,6 +26255,23 @@ void X86TargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       }
     }
     return;
+  case 'L':
+    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
+      if (C->getZExtValue() == 0xff || C->getZExtValue() == 0xffff ||
+          (Subtarget->is64Bit() && C->getZExtValue() == 0xffffffff)) {
+        Result = DAG.getTargetConstant(C->getSExtValue(), Op.getValueType());
+        break;
+      }
+    }
+    return;
+  case 'M':
+    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
+      if (C->getZExtValue() <= 3) {
+        Result = DAG.getTargetConstant(C->getZExtValue(), Op.getValueType());
+        break;
+      }
+    }
+    return;
   case 'N':
     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
       if (C->getZExtValue() <= 255) {
@@ -26263,6 +26280,14 @@ void X86TargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       }
     }
     return;
+  case 'O':
+    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
+      if (C->getZExtValue() <= 127) {
+        Result = DAG.getTargetConstant(C->getZExtValue(), Op.getValueType());
+        break;
+      }
+    }
+    return;
   case 'e': {
     // 32-bit signed value
     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
diff --git a/test/CodeGen/X86/x86-inline-asm-validation.ll b/test/CodeGen/X86/x86-inline-asm-validation.ll
new file mode 100644
index 00000000000..56bdc48b0e4
--- /dev/null
+++ b/test/CodeGen/X86/x86-inline-asm-validation.ll
@@ -0,0 +1,34 @@
+; RUN: llc -mtriple i686-gnu -filetype asm -o - %s 2>&1 | FileCheck %s
+
+define void @test_L_ff() {
+entry:
+  call void asm "", "L,~{dirflag},~{fpsr},~{flags}"(i32 255)
+  ret void
+}
+
+; CHECK-NOT: error: invalid operand for inline asm constraint 'L'
+
+define void @test_L_ffff() {
+entry:
+  call void asm "", "L,~{dirflag},~{fpsr},~{flags}"(i32 65535)
+  ret void
+}
+
+; CHECK-NOT: error: invalid operand for inline asm constraint 'L'
+
+define void @test_M_1() {
+entry:
+  call void asm "", "M,~{dirflag},~{fpsr},~{flags}"(i32 1)
+  ret void
+}
+
+; CHECK-NOT: error: invalid operand for inline asm constraint 'M'
+
+define void @test_O_64() {
+entry:
+  call void asm "", "O,~{dirflag},~{fpsr},~{flags}"(i32 64)
+  ret void
+}
+
+; CHECK-NOT: error: invalid operand for inline asm constraint 'O'
+
-- 
2.34.1