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

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 927ff2c8101cef4527185f621c9dea8baefa71b1..9525ed0a22057c907abd5d1f6b37db6c2c817839 100644 (file)
--- 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 (file)
index 0000000..56bdc48
--- /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'
+