Remove RSTRegClass case from loadRegFromStackSlot

and storeRegToStackSlot.  Evan and I concluded this
should never be needed and it appears to be true.
(It if is needed, adjustment would be needed for
long double to work.)

llvm-svn: 42049

2 files changed, 3 insertions, 5 deletions

diff --git a/llvm/lib/Target/X86/X86FloatingPoint.cpp b/llvm/lib/Target/X86/X86FloatingPoint.cpp
index ac6d6145e51..179a71e03fa 100644
--- a/llvm/lib/Target/X86/X86FloatingPoint.cpp
+++ b/llvm/lib/Target/X86/X86FloatingPoint.cpp
@@ -608,7 +608,7 @@ void FPS::handleOneArgFP(MachineBasicBlock::iterator &I) {
   // If we have one _and_ we don't want to pop the operand, duplicate the value
   // on the stack instead of moving it.  This ensure that popping the value is
   // always ok.
-  // Ditto FISTTP16m, FISTTP32m, FISTTP64m.
+  // Ditto FISTTP16m, FISTTP32m, FISTTP64m, ST_FpP80m.
   //
   if (!KillsSrc &&
       (MI->getOpcode() == X86::IST_Fp64m32 ||
diff --git a/llvm/lib/Target/X86/X86RegisterInfo.cpp b/llvm/lib/Target/X86/X86RegisterInfo.cpp
index 4a8c275bc54..df50efe896a 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.cpp
+++ b/llvm/lib/Target/X86/X86RegisterInfo.cpp
@@ -170,9 +170,7 @@ void X86RegisterInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
     Opc = X86::MOV16_mr;
   } else if (RC == &X86::RFP80RegClass) {
     Opc = X86::ST_FpP80m;   // pops
-  } else if (RC == &X86::RFP64RegClass || RC == &X86::RSTRegClass) {
-    /// FIXME spilling long double values as 64 bit does not work.
-    /// We need RST80, unfortunately.
+  } else if (RC == &X86::RFP64RegClass) {
     Opc = X86::ST_Fp64m;
   } else if (RC == &X86::RFP32RegClass) {
     Opc = X86::ST_Fp32m;
@@ -211,7 +209,7 @@ void X86RegisterInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
     Opc = X86::MOV16_rm;
   } else if (RC == &X86::RFP80RegClass) {
     Opc = X86::LD_Fp80m;
-  } else if (RC == &X86::RFP64RegClass || RC == &X86::RSTRegClass) {
+  } else if (RC == &X86::RFP64RegClass) {
     Opc = X86::LD_Fp64m;
   } else if (RC == &X86::RFP32RegClass) {
     Opc = X86::LD_Fp32m;