- Added MRegisterInfo::getCrossCopyRegClass() hook. For register classes where reg to reg copies are not possible, this returns another register class which registers in the specified register class can be copied to (and copy back from).

- X86 copyRegToReg() now supports copying between EFLAGS and GR32 / GR64 registers.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42372 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 30 insertions, 0 deletions

diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index 98955a305e..fdb259cd0e 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -234,6 +234,30 @@ void X86RegisterInfo::copyRegToReg(MachineBasicBlock &MBB,
                                    const TargetRegisterClass *DestRC,
                                    const TargetRegisterClass *SrcRC) const {
   if (DestRC != SrcRC) {
+    // Moving EFLAGS to / from another register requires a push and a pop.
+    if (SrcRC == &X86::CCRRegClass) {
+      assert(SrcReg == X86::EFLAGS);
+      if (DestRC == &X86::GR64RegClass) {
+        BuildMI(MBB, MI, TII.get(X86::PUSHFQ));
+        BuildMI(MBB, MI, TII.get(X86::POP64r), DestReg);
+        return;
+      } else if (DestRC == &X86::GR32RegClass) {
+        BuildMI(MBB, MI, TII.get(X86::PUSHFD));
+        BuildMI(MBB, MI, TII.get(X86::POP32r), DestReg);
+        return;
+      }
+    } else if (DestRC == &X86::CCRRegClass) {
+      assert(DestReg == X86::EFLAGS);
+      if (SrcRC == &X86::GR64RegClass) {
+        BuildMI(MBB, MI, TII.get(X86::PUSH64r)).addReg(SrcReg);
+        BuildMI(MBB, MI, TII.get(X86::POPFQ));
+        return;
+      } else if (SrcRC == &X86::GR32RegClass) {
+        BuildMI(MBB, MI, TII.get(X86::PUSH32r)).addReg(SrcReg);
+        BuildMI(MBB, MI, TII.get(X86::POPFD));
+        return;
+      }
+    }
     cerr << "Not yet supported!";
     abort();
   }
@@ -272,6 +296,12 @@ void X86RegisterInfo::copyRegToReg(MachineBasicBlock &MBB,
   BuildMI(MBB, MI, TII.get(Opc), DestReg).addReg(SrcReg);
 }
 
+const TargetRegisterClass *
+X86RegisterInfo::getCrossCopyRegClass(const TargetRegisterClass *RC) const {
+  if (RC == &X86::CCRRegClass)
+    return &X86::GR32RegClass;
+  return NULL;
+}
 
 void X86RegisterInfo::reMaterialize(MachineBasicBlock &MBB,
                                     MachineBasicBlock::iterator I,