Added tail call optimization to the x86 back end. It can be

enabled by passing -tailcallopt to llc.  The optimization is
performed if the following conditions are satisfied:
* caller/callee are fastcc
* elf/pic is disabled OR
  elf/pic enabled + callee is in module + callee has
  visibility protected or hidden

llvm-svn: 42870

1 files changed, 35 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86InstrX86-64.td b/llvm/lib/Target/X86/X86InstrX86-64.td
index f6f48a21d47..f501b5ec558 100644
--- a/llvm/lib/Target/X86/X86InstrX86-64.td
+++ b/llvm/lib/Target/X86/X86InstrX86-64.td
@@ -102,6 +102,23 @@ let isCall = 1 in
                           "call\t{*}$dst", []>;
   }
 
+
+
+let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1 in
+def TCRETURNdi64 : I<0, Pseudo, (outs), (ins i64imm:$dst, i32imm:$offset),
+                 "#TC_RETURN $dst $offset",
+                 []>;
+
+let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1 in
+def TCRETURNri64 : I<0, Pseudo, (outs), (ins GR64:$dst, i32imm:$offset),
+                 "#TC_RETURN $dst $offset",
+                 []>;
+
+
+let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1 in
+  def TAILJMPr64 : I<0xFF, MRM4r, (outs), (ins GR64:$dst), "jmp{q}\t{*}$dst  # TAILCALL",
+                 []>;     
+
 // Branches
 let isBranch = 1, isTerminator = 1, isBarrier = 1 in {
   def JMP64r     : I<0xFF, MRM4r, (outs), (ins GR64:$dst), "jmp{q}\t{*}$dst",
@@ -1105,6 +1122,24 @@ def : Pat<(X86tailcall (i64 texternalsym:$dst)),
 def : Pat<(X86tailcall GR64:$dst),
           (CALL64r GR64:$dst)>;
 
+
+// tailcall stuff
+def : Pat<(X86tailcall GR32:$dst),
+          (TAILCALL)>;
+def : Pat<(X86tailcall (i64 tglobaladdr:$dst)),
+          (TAILCALL)>;
+def : Pat<(X86tailcall (i64 texternalsym:$dst)),
+          (TAILCALL)>;
+
+def : Pat<(X86tcret GR64:$dst, imm:$off),
+          (TCRETURNri64 GR64:$dst, imm:$off)>;
+
+def : Pat<(X86tcret (i64 tglobaladdr:$dst), imm:$off),
+          (TCRETURNdi64 texternalsym:$dst, imm:$off)>;
+
+def : Pat<(X86tcret (i64 texternalsym:$dst), imm:$off),
+          (TCRETURNdi64 texternalsym:$dst, imm:$off)>;
+
 // Comparisons.
 
 // TEST R,R is smaller than CMP R,0