Add support for S and D constraints, as needed to compile the linux kernel.

llvm-svn: 29746

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 4f1feb1c615..e1e3ef38f95 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -4184,6 +4184,8 @@ X86TargetLowering::getConstraintType(char ConstraintLetter) const {
   case 'Q':
   case 'x':
   case 'Y':
+  case 'S':
+  case 'D':
     return C_RegisterClass;
   default: return TargetLowering::getConstraintType(ConstraintLetter);
   }
@@ -4197,6 +4199,14 @@ getRegClassForInlineAsmConstraint(const std::string &Constraint,
     // FIXME: not handling MMX registers yet ('y' constraint).
     switch (Constraint[0]) {      // GCC X86 Constraint Letters
     default: break;  // Unknown constraint letter
+    case 'S':   // ESI
+      if (VT == MVT::i32)
+	return make_vector<unsigned>(X86::ESI,0);
+      break;
+    case 'D':   // EDI
+      if (VT == MVT::i32)
+	return make_vector<unsigned>(X86::EDI,0);
+      break;
     case 'A':   // EAX/EDX
       if (VT == MVT::i32 || VT == MVT::i64)
         return make_vector<unsigned>(X86::EAX, X86::EDX, 0);