Do away with addLegalFPImmediate. Add a target hook isFPImmLegal which returns true if the fp immediate can be natively codegened by target.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85281 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 16 insertions, 5 deletions

diff --git a/lib/Target/SystemZ/SystemZISelLowering.cpp b/lib/Target/SystemZ/SystemZISelLowering.cpp
index 07e0d83058..eb4d250504 100644
--- a/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -53,11 +53,6 @@ SystemZTargetLowering::SystemZTargetLowering(SystemZTargetMachine &tm) :
   if (!UseSoftFloat) {
     addRegisterClass(MVT::f32, SystemZ::FP32RegisterClass);
     addRegisterClass(MVT::f64, SystemZ::FP64RegisterClass);
-
-    addLegalFPImmediate(APFloat(+0.0));  // lzer
-    addLegalFPImmediate(APFloat(+0.0f)); // lzdr
-    addLegalFPImmediate(APFloat(-0.0));  // lzer + lner
-    addLegalFPImmediate(APFloat(-0.0f)); // lzdr + lndr
   }
 
   // Compute derived properties from the register classes
@@ -169,6 +164,17 @@ SDValue SystemZTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
   }
 }
 
+bool SystemZTargetLowering::isFPImmLegal(const APFloat &Imm) const {
+  if (UseSoftFloat)
+    return false;
+
+  // +0.0  lzer
+  // +0.0f lzdr
+  // -0.0  lzer + lner
+  // -0.0f lzdr + lndr
+  return Imm.isZero() || Imm.isNegZero();
+}
+
 //===----------------------------------------------------------------------===//
 //                       SystemZ Inline Assembly Support
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/SystemZ/SystemZISelLowering.h b/lib/Target/SystemZ/SystemZISelLowering.h
index c2c24bc1f3..76af03de0a 100644
--- a/lib/Target/SystemZ/SystemZISelLowering.h
+++ b/lib/Target/SystemZ/SystemZISelLowering.h
@@ -89,6 +89,11 @@ namespace llvm {
                                                    MachineBasicBlock *BB,
                     DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) const;
 
+    /// isFPImmLegal - Returns true if the target can instruction select the
+    /// specified FP immediate natively. If false, the legalizer will
+    /// materialize the FP immediate as a load from a constant pool.
+    virtual bool isFPImmLegal(const APFloat &Imm) const;
+
   private:
     SDValue LowerCCCCallTo(SDValue Chain, SDValue Callee,
                            CallingConv::ID CallConv, bool isVarArg,