For now, don't split live intervals around x87 stack register barriers. FpGET_ST0_80 must be right after a call instruction (and ADJCALLSTACKUP) so we need to find a way to prevent reload of x87 registers between them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58230 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 04f10c0..c08fdd8 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -2411,6 +2411,14 @@
   return false;
 }
 
+bool X86InstrInfo::
+IgnoreRegisterClassBarriers(const TargetRegisterClass *RC) const {
+  // FIXME: Ignore bariers of x87 stack registers 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;
+}
+
 const TargetRegisterClass *X86InstrInfo::getPointerRegClass() const {
   const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
   if (Subtarget->is64Bit())