[Inliner] Restrict soft-float inlining penalty.

The penalty is currently getting applied in a bunch of places where it
doesn't make sense, like bitcasts (which are free) and calls (which
were getting the call penalty applied twice). Instead, just apply the
penalty to binary operators and floating-point casts.

While I'm here, also fix getFPOpCost() to do the right thing in more
cases, so we don't have to dig into function attributes.

Differential Revision: https://reviews.llvm.org/D41522

llvm-svn: 321332

3 files changed, 23 insertions, 32 deletions

diff --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
index 9ba1e119494..8d186e2d5af 100644
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -701,6 +701,22 @@ bool CallAnalyzer::visitCastInst(CastInst &I) {
   // Disable SROA in the face of arbitrary casts we don't whitelist elsewhere.
   disableSROA(I.getOperand(0));
 
+  // If this is a floating-point cast, and the target says this operation
+  // is expensive, this may eventually become a library call. Treat the cost
+  // as such.
+  switch (I.getOpcode()) {
+  case Instruction::FPTrunc:
+  case Instruction::FPExt:
+  case Instruction::UIToFP:
+  case Instruction::SIToFP:
+  case Instruction::FPToUI:
+  case Instruction::FPToSI:
+    if (TTI.getFPOpCost(I.getType()) == TargetTransformInfo::TCC_Expensive)
+      Cost += InlineConstants::CallPenalty;
+  default:
+    break;
+  }
+
   return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I);
 }
 
@@ -1079,6 +1095,13 @@ bool CallAnalyzer::visitBinaryOperator(BinaryOperator &I) {
   disableSROA(LHS);
   disableSROA(RHS);
 
+  // If the instruction is floating point, and the target says this operation
+  // is expensive, this may eventually become a library call. Treat the cost
+  // as such.
+  if (I.getType()->isFloatingPointTy() &&
+      TTI.getFPOpCost(I.getType()) == TargetTransformInfo::TCC_Expensive)
+    Cost += InlineConstants::CallPenalty;
+
   return false;
 }
 
@@ -1548,17 +1571,6 @@ bool CallAnalyzer::analyzeBlock(BasicBlock *BB,
     if (isa<ExtractElementInst>(I) || I->getType()->isVectorTy())
       ++NumVectorInstructions;
 
-    // If the instruction is floating point, and the target says this operation
-    // is expensive or the function has the "use-soft-float" attribute, this may
-    // eventually become a library call. Treat the cost as such.
-    if (I->getType()->isFloatingPointTy()) {
-      // If the function has the "use-soft-float" attribute, mark it as
-      // expensive.
-      if (TTI.getFPOpCost(I->getType()) == TargetTransformInfo::TCC_Expensive ||
-          (F.getFnAttribute("use-soft-float").getValueAsString() == "true"))
-        Cost += InlineConstants::CallPenalty;
-    }
-
     // If the instruction simplified to a constant, there is no cost to this
     // instruction. Visit the instructions using our InstVisitor to account for
     // all of the per-instruction logic. The visit tree returns true if we
diff --git a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
index cae01e415ef..43d7888075b 100644
--- a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
@@ -394,25 +394,6 @@ int ARMTTIImpl::getAddressComputationCost(Type *Ty, ScalarEvolution *SE,
   return 1;
 }
 
-int 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;
-}
-
 int 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 99353a3219a..cd9fa070902 100644
--- a/llvm/lib/Target/ARM/ARMTargetTransformInfo.h
+++ b/llvm/lib/Target/ARM/ARMTargetTransformInfo.h
@@ -156,8 +156,6 @@ public:
   int getAddressComputationCost(Type *Val, ScalarEvolution *SE, 
                                 const SCEV *Ptr);
 
-  int getFPOpCost(Type *Ty);
-
   int getArithmeticInstrCost(
       unsigned Opcode, Type *Ty,
       TTI::OperandValueKind Op1Info = TTI::OK_AnyValue,