[SystemZ] Add CodeGen support for scalar f64 ops in vector registers

The z13 vector facility includes some instructions that operate only on the
high f64 in a v2f64, effectively extending the FP register set from 16
to 32 registers.  It's still better to use the old instructions if the
operands happen to fit though, since the older instructions have a shorter
encoding.

Based on a patch by Richard Sandiford.

llvm-svn: 236524

1 files changed, 8 insertions, 3 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index 391cb8c6fc9..ff79a48179f 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -91,9 +91,14 @@ SystemZTargetLowering::SystemZTargetLowering(const TargetMachine &tm,
     addRegisterClass(MVT::i32, &SystemZ::GRX32BitRegClass);
   else
     addRegisterClass(MVT::i32, &SystemZ::GR32BitRegClass);
-  addRegisterClass(MVT::i64,  &SystemZ::GR64BitRegClass);
-  addRegisterClass(MVT::f32,  &SystemZ::FP32BitRegClass);
-  addRegisterClass(MVT::f64,  &SystemZ::FP64BitRegClass);
+  addRegisterClass(MVT::i64, &SystemZ::GR64BitRegClass);
+  if (Subtarget.hasVector()) {
+    addRegisterClass(MVT::f32, &SystemZ::VR32BitRegClass);
+    addRegisterClass(MVT::f64, &SystemZ::VR64BitRegClass);
+  } else {
+    addRegisterClass(MVT::f32, &SystemZ::FP32BitRegClass);
+    addRegisterClass(MVT::f64, &SystemZ::FP64BitRegClass);
+  }
   addRegisterClass(MVT::f128, &SystemZ::FP128BitRegClass);
 
   if (Subtarget.hasVector()) {