Add TargetInstrInfo::isSafeToMoveRegisterClassDefs. It returns true if it's safe to move an instruction which defines a value in the register class. Replace pre-splitting specific IgnoreRegisterClassBarriers with this new hook.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63936 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 8e3985f..5778849 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -2483,11 +2483,11 @@
 }
 
 bool X86InstrInfo::
-IgnoreRegisterClassBarriers(const TargetRegisterClass *RC) const {
-  // FIXME: Ignore bariers of x87 stack registers for now. We can't
+isSafeToMoveRegClassDefs(const TargetRegisterClass *RC) const {
+  // FIXME: Return false for x87 stack register classes for now. We can't
   // allow any loads of these registers before FpGet_ST0_80.
-  return RC == &X86::CCRRegClass || RC == &X86::RFP32RegClass ||
-    RC == &X86::RFP64RegClass || RC == &X86::RFP80RegClass;
+  return !(RC == &X86::CCRRegClass || RC == &X86::RFP32RegClass ||
+           RC == &X86::RFP64RegClass || RC == &X86::RFP80RegClass);
 }
 
 const TargetRegisterClass *X86InstrInfo::getPointerRegClass() const {