Value soft float calls as more expensive in the inliner.

Summary: When evaluating floating point instructions in the inliner, ask the TTI whether it is an expensive operation.  By default, it's not an expensive operation.  This keeps the default behavior the same as before.  The ARM TTI has been updated to return back TCC_Expensive for targets which don't have hardware floating point.

Reviewers: chandlerc, echristo

Reviewed By: echristo

Subscribers: t.p.northover, aemerson, llvm-commits

Differential Revision: http://reviews.llvm.org/D6936

llvm-svn: 228263

3 files changed, 23 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/ARMSubtarget.h b/llvm/lib/Target/ARM/ARMSubtarget.h
index dd1ab3aabcf..64d499a4dc5 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.h
+++ b/llvm/lib/Target/ARM/ARMSubtarget.h
@@ -310,7 +310,8 @@ public:
   bool hasCRC() const { return HasCRC; }
   bool hasVirtualization() const { return HasVirtualization; }
   bool useNEONForSinglePrecisionFP() const {
-    return hasNEON() && UseNEONForSinglePrecisionFP; }
+    return hasNEON() && UseNEONForSinglePrecisionFP;
+  }
 
   bool hasDivide() const { return HasHardwareDivide; }
   bool hasDivideInARMMode() const { return HasHardwareDivideInARM; }
diff --git a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
index 1cb1efb1924..4e1b371640b 100644
--- a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
@@ -314,6 +314,25 @@ unsigned ARMTTIImpl::getAddressComputationCost(Type *Ty, bool IsComplex) {
   return 1;
 }
 
+unsigned ARMTTIImpl::getFPOpCost(Type *Ty) {
+  // Use similar logic that's in ARMISelLowering:
+  // Any ARM CPU with VFP2 has floating point, but Thumb1 didn't have access
+  // to VFP.
+
+  if (ST->hasVFP2() && !ST->isThumb1Only()) {
+    if (Ty->isFloatTy()) {
+      return TargetTransformInfo::TCC_Basic;
+    }
+
+    if (Ty->isDoubleTy()) {
+      return ST->isFPOnlySP() ? TargetTransformInfo::TCC_Expensive :
+        TargetTransformInfo::TCC_Basic;
+    }
+  }
+
+  return TargetTransformInfo::TCC_Expensive;
+}
+
 unsigned ARMTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index,
                                     Type *SubTp) {
   // We only handle costs of reverse and alternate shuffles for now.
diff --git a/llvm/lib/Target/ARM/ARMTargetTransformInfo.h b/llvm/lib/Target/ARM/ARMTargetTransformInfo.h
index 6167fae9c8a..97590f60893 100644
--- a/llvm/lib/Target/ARM/ARMTargetTransformInfo.h
+++ b/llvm/lib/Target/ARM/ARMTargetTransformInfo.h
@@ -114,6 +114,8 @@ public:
 
   unsigned getAddressComputationCost(Type *Val, bool IsComplex);
 
+  unsigned getFPOpCost(Type *Ty);
+
   unsigned getArithmeticInstrCost(
       unsigned Opcode, Type *Ty,
       TTI::OperandValueKind Op1Info = TTI::OK_AnyValue,