Add basic support for code generation of

addrspace(257) -> FS relative on x86.  Patch by Zoltan Varga!

llvm-svn: 70992

docs/CodeGenerator.html

@@ -1844,11 +1844,13 @@ OperandTy: VirtReg, | VirtReg, UnsImm, VirtReg,   SignExtImm
    segment.  LLVM address space 0 is the default address space, which includes
    the stack, and any unqualified memory accesses in a program.  Address spaces
    1-255 are currently reserved for user-defined code.  The GS-segment is
-   represented by address space 256.  Other x86 segments have yet to be
-   allocated address space numbers.</p>
+   represented by address space 256, while the FS-segment is represented by 
+   address space 257. Other x86 segments have yet to be allocated address space
+   numbers.</p>
 
-<p>Some operating systems use the GS-segment to implement TLS, so care should be
-   taken when reading and writing to address space 256 on these platforms.</p>
+<p>Some operating systems use the FS/GS-segment to implement TLS, so care 
+   should be taken when reading and writing to address space 256/257 on these
+   platforms.</p>
 
 </div>
 

lib/Target/X86/X86Instr64bit.td

@@ -1326,6 +1326,11 @@ def MOV64GSrm : RI<0x8B, MRMSrcMem, (outs GR64:$dst), (ins i64mem:$src),
                  "movq\t%gs:$src, $dst",
                  [(set GR64:$dst, (gsload addr:$src))]>, SegGS;
 
+let AddedComplexity = 5 in
+def MOV64FSrm : RI<0x8B, MRMSrcMem, (outs GR64:$dst), (ins i64mem:$src),
+                 "movq\t%fs:$src, $dst",
+                 [(set GR64:$dst, (fsload addr:$src))]>, SegFS;
+
 //===----------------------------------------------------------------------===//
 // Atomic Instructions
 //===----------------------------------------------------------------------===//

lib/Target/X86/X86InstrInfo.td

@@ -345,6 +345,13 @@ def gsload : PatFrag<(ops node:$ptr), (load node:$ptr), [{
   return false;
 }]>;
 
+def fsload : PatFrag<(ops node:$ptr), (load node:$ptr), [{
+  if (const Value *Src = cast<LoadSDNode>(N)->getSrcValue())
+    if (const PointerType *PT = dyn_cast<PointerType>(Src->getType()))
+      return PT->getAddressSpace() == 257;
+  return false;
+}]>;
+
 def loadi8  : PatFrag<(ops node:$ptr), (i8  (load node:$ptr)), [{
   if (const Value *Src = cast<LoadSDNode>(N)->getSrcValue())
     if (const PointerType *PT = dyn_cast<PointerType>(Src->getType()))
@@ -3004,6 +3011,11 @@ def GS_MOV32rm : I<0x8B, MRMSrcMem, (outs GR32:$dst), (ins i32mem:$src),
                    "movl\t%gs:$src, $dst",
                    [(set GR32:$dst, (gsload addr:$src))]>, SegGS;
 
+let AddedComplexity = 5 in
+def FS_MOV32rm : I<0x8B, MRMSrcMem, (outs GR32:$dst), (ins i32mem:$src),
+                   "movl\t%fs:$src, $dst",
+                   [(set GR32:$dst, (fsload addr:$src))]>, SegFS;
+
 //===----------------------------------------------------------------------===//
 // DWARF Pseudo Instructions
 //

test/CodeGen/X86/movfs.ll

@@ -0,0 +1,8 @@
+; RUN: llvm-as < %s | llc -march=x86 | grep fs
+
+define i32 @foo() nounwind readonly {
+entry:
+	%tmp = load i32* addrspace(257)* getelementptr (i32* addrspace(257)* inttoptr (i32 72 to i32* addrspace(257)*), i32 31)		; <i32*> [#uses=1]
+	%tmp1 = load i32* %tmp		; <i32> [#uses=1]
+	ret i32 %tmp1
+}