[PowerPC] Implement hasBitPreservingFPLogic for types that can be supported

This is the PPC-specific non-controversial part of
https://reviews.llvm.org/D44548 that simply enables this combine for PPC
since PPC has these instructions.
This commit will allow the target-independent portion to be truly target
independent.

llvm-svn: 344077

2 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 1e51393dbfa..f4fd8e1db4c 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -14320,6 +14320,15 @@ bool PPCTargetLowering::mayBeEmittedAsTailCall(const CallInst *CI) const {
   return getTargetMachine().shouldAssumeDSOLocal(*Caller->getParent(), Callee);
 }
 
+bool PPCTargetLowering::hasBitPreservingFPLogic(EVT VT) const {
+  if (!Subtarget.hasVSX())
+    return false;
+  if (Subtarget.hasP9Vector() && VT == MVT::f128)
+    return true;
+  return VT == MVT::f32 || VT == MVT::f64 ||
+    VT == MVT::v4f32 || VT == MVT::v2f64;
+}
+
 bool PPCTargetLowering::
 isMaskAndCmp0FoldingBeneficial(const Instruction &AndI) const {
   const Value *Mask = AndI.getOperand(1);
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index 0872ac248ec..9709d6bb09e 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -1127,6 +1127,7 @@ namespace llvm {
     // tail call. This will cause the optimizers to attempt to move, or
     // duplicate return instructions to help enable tail call optimizations.
     bool mayBeEmittedAsTailCall(const CallInst *CI) const override;
+    bool hasBitPreservingFPLogic(EVT VT) const override;
     bool isMaskAndCmp0FoldingBeneficial(const Instruction &AndI) const override;
   }; // end class PPCTargetLowering