Add a emitUnaryFloatFnCall version that fetches the function name from TLI

Summary:
In several places in the code we use the following pattern:

  if (hasUnaryFloatFn(&TLI, Ty, LibFunc_tan, LibFunc_tanf, LibFunc_tanl)) {
    [...]
    Value *Res = emitUnaryFloatFnCall(X, TLI.getName(LibFunc_tan), B, Attrs);
    [...]
  }

In short, we check if there is a lib-function for a certain type, and then
we _always_ fetch the name of the "double" version of the lib function and
construct a call to the appropriate function, that we just checked exists,
using that "double" name as a basis.

This is of course a problem in cases where the target doesn't support the
"double" version, but e.g. only the "float" version.

In that case TLI.getName(LibFunc_tan) returns "", and
emitUnaryFloatFnCall happily appends an "f" to "", and we erroneously end
up with a call to a function called "f".

To solve this, the above pattern is changed to

  if (hasUnaryFloatFn(&TLI, Ty, LibFunc_tan, LibFunc_tanf, LibFunc_tanl)) {
    [...]
    Value *Res = emitUnaryFloatFnCall(X, &TLI, LibFunc_tan, LibFunc_tanf,
                                      LibFunc_tanl, B, Attrs);
    [...]
  }

I.e instead of first fetching the name of the "double" version and then
letting emitUnaryFloatFnCall() add the final "f" or "l", we let
emitUnaryFloatFnCall() fetch the right name from TLI.

Reviewers: eli.friedman, efriedma

Reviewed By: efriedma

Subscribers: efriedma, bjope, llvm-commits

Differential Revision: https://reviews.llvm.org/D53370

llvm-svn: 344725

1 files changed, 43 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
index 06d197be095..3466dedd323 100644
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -765,6 +765,24 @@ bool llvm::hasUnaryFloatFn(const TargetLibraryInfo *TLI, Type *Ty,
   }
 }
 
+StringRef llvm::getUnaryFloatFn(const TargetLibraryInfo *TLI, Type *Ty,
+                                LibFunc DoubleFn, LibFunc FloatFn,
+                                LibFunc LongDoubleFn) {
+  assert(hasUnaryFloatFn(TLI, Ty, DoubleFn, FloatFn, LongDoubleFn) &&
+         "Cannot get name for unavailable function!");
+
+  switch (Ty->getTypeID()) {
+  case Type::HalfTyID:
+    llvm_unreachable("No name for HalfTy!");
+  case Type::FloatTyID:
+    return TLI->getName(FloatFn);
+  case Type::DoubleTyID:
+    return TLI->getName(DoubleFn);
+  default:
+    return TLI->getName(LongDoubleFn);
+  }
+}
+
 //- Emit LibCalls ------------------------------------------------------------//
 
 Value *llvm::castToCStr(Value *V, IRBuilder<> &B) {
@@ -942,10 +960,10 @@ static void appendTypeSuffix(Value *Op, StringRef &Name,
   }
 }
 
-Value *llvm::emitUnaryFloatFnCall(Value *Op, StringRef Name, IRBuilder<> &B,
-                                  const AttributeList &Attrs) {
-  SmallString<20> NameBuffer;
-  appendTypeSuffix(Op, Name, NameBuffer);
+static Value *emitUnaryFloatFnCallHelper(Value *Op, StringRef Name,
+                                         IRBuilder<> &B,
+                                         const AttributeList &Attrs) {
+  assert((Name != "") && "Must specify Name to emitUnaryFloatFnCall");
 
   Module *M = B.GetInsertBlock()->getModule();
   Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
@@ -964,8 +982,29 @@ Value *llvm::emitUnaryFloatFnCall(Value *Op, StringRef Name, IRBuilder<> &B,
   return CI;
 }
 
+Value *llvm::emitUnaryFloatFnCall(Value *Op, StringRef Name, IRBuilder<> &B,
+                                  const AttributeList &Attrs) {
+  SmallString<20> NameBuffer;
+  appendTypeSuffix(Op, Name, NameBuffer);
+
+  return emitUnaryFloatFnCallHelper(Op, Name, B, Attrs);
+}
+
+Value *llvm::emitUnaryFloatFnCall(Value *Op, const TargetLibraryInfo *TLI,
+                                  LibFunc DoubleFn, LibFunc FloatFn,
+                                  LibFunc LongDoubleFn, IRBuilder<> &B,
+                                  const AttributeList &Attrs) {
+  // Get the name of the function according to TLI.
+  StringRef Name = getUnaryFloatFn(TLI, Op->getType(),
+                                   DoubleFn, FloatFn, LongDoubleFn);
+
+  return emitUnaryFloatFnCallHelper(Op, Name, B, Attrs);
+}
+
 Value *llvm::emitBinaryFloatFnCall(Value *Op1, Value *Op2, StringRef Name,
                                    IRBuilder<> &B, const AttributeList &Attrs) {
+  assert((Name != "") && "Must specify Name to emitBinaryFloatFnCall");
+
   SmallString<20> NameBuffer;
   appendTypeSuffix(Op1, Name, NameBuffer);