On x86-64, for a varargs function, don't store the xmm registers to

the register save area if %al is 0. This avoids touching xmm
regsiters when they aren't actually used.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79061 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 1 deletions

diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index 9e6cd81..3ac6e51 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -243,7 +243,12 @@ namespace llvm {
       MUL_IMM,
       
       // PTEST - Vector bitwise comparisons
-      PTEST
+      PTEST,
+
+      // VASTART_SAVE_XMM_REGS - Save xmm argument registers to the stack,
+      // according to %al. An operator is needed so that this can be expanded
+      // with control flow.
+      VASTART_SAVE_XMM_REGS
     };
   }
 
@@ -715,6 +720,11 @@ namespace llvm {
                                                           MachineBasicBlock *BB,
                                                         unsigned cmovOpc) const;
 
+    /// Utility function to emit the xmm reg save portion of va_start.
+    MachineBasicBlock *EmitVAStartSaveXMMRegsWithCustomInserter(
+                                                   MachineInstr *BInstr,
+                                                   MachineBasicBlock *BB) const;
+
     /// Emit nodes that will be selected as "test Op0,Op0", or something
     /// equivalent, for use with the given x86 condition code.
     SDValue EmitTest(SDValue Op0, unsigned X86CC, SelectionDAG &DAG);