[PATCH] TLI: Add interface for querying whether a function is vectorizable.

[Arnold]

Sent from my iPhone

> On Mar 5, 2015, at 8:36 PM, "hfinkel at anl.gov" <hfinkel at anl.gov> wrote:
> 
> ================
> Comment at: lib/Analysis/TargetLibraryInfo.cpp:758
> @@ -753,1 +757,3 @@
> 
> +static bool compareByScalarFnName(const VecDesc &LHS, const VecDesc &RHS) {
> +  return std::strncmp(LHS.ScalarFnName, RHS.ScalarFnName,
> ----------------
> It looks like all of these comparison functions are only used once. Please make them lambdas at their current call sites.


Why? He had this in his original patch. In my review I argued that using static function makes it obvious what is going on. Especially, since the body of the lambdas look very similar.

Compare:

std::sort(VectorDescs.begin(), VectorDescs.end(), compareByScalarName)

std::sort(ScalarDescs.begin(), ScalarDescs.end(), compareByVectorName)

std::lower_bound(VectorDescs.begin(), VectorDescs.end(), FunctionName, compareScalarNameWith)

etc.

+void TargetLibraryInfoImpl::addVectorizableFunctions(ArrayRef<VecDesc> Fns) {
+  VectorDescs.insert(VectorDescs.end(), Fns.begin(), Fns.end());
+  std::sort(VectorDescs.begin(), VectorDescs.end(),
+            [](const VecDesc &LHS, const VecDesc &RHS) {
+              return std::strncmp(LHS.ScalarFnName, RHS.ScalarFnName,
+                                  std::strlen(RHS.ScalarFnName)) < 0;
+            });
+
+  ScalarDescs.insert(ScalarDescs.end(), Fns.begin(), Fns.end());
+  std::sort(ScalarDescs.begin(), ScalarDescs.end(),
+            [](const VecDesc &LHS, const VecDesc &RHS) {
+              return std::strncmp(LHS.VectorFnName, RHS.VectorFnName,
+                                  std::strlen(RHS.VectorFnName)) < 0;
+            });
+}
+
+bool TargetLibraryInfoImpl::isFunctionVectorizable(StringRef funcName) const {
+  funcName = sanitizeFunctionName(funcName);
+  if (funcName.empty())
+    return false;
+
+  std::vector<VecDesc>::const_iterator I = std::lower_bound(
+      VectorDescs.begin(), VectorDescs.end(), funcName,
+      [](const VecDesc &LHS, StringRef S) {
+        return std::strncmp(LHS.ScalarFnName, S.data(), S.size()) < 0;
+      });
+  return I != VectorDescs.end();
+}
+
+StringRef TargetLibraryInfoImpl::getVectorizedFunction(StringRef F,
+                                                       unsigned VF) const {
+  F = sanitizeFunctionName(F);
+  if (F.empty())
+    return F;
+  std::vector<VecDesc>::const_iterator I = std::lower_bound(
+      VectorDescs.begin(), VectorDescs.end(), F,
+      [](const VecDesc &LHS, StringRef S) {
+        return std::strncmp(LHS.ScalarFnName, S.data(), S.size()) < 0;
+      });
+  while (I != VectorDescs.end() && StringRef(I->ScalarFnName) == F) {
+    if (I->VectorizationFactor == VF)
+      return I->VectorFnName;
+    ++I;
+  }
+  return StringRef();
+}


I don't think we should/ must use lambdas   (If there is just a single use) at the cost of readability.

compareWithScalarFnName is used in two places.

> http://reviews.llvm.org/D8093
> 
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