diff --git a/clang-tools-extra/clang-tidy/.clang-tidy b/clang-tools-extra/clang-tidy/.clang-tidy
index ae554c6668a84..d290901730405 100644
--- a/clang-tools-extra/clang-tidy/.clang-tidy
+++ b/clang-tools-extra/clang-tidy/.clang-tidy
@@ -16,7 +16,6 @@ Checks: >
   performance-*,
   -performance-enum-size,
   -performance-no-int-to-ptr,
-  -performance-type-promotion-in-math-fn,
   -performance-unnecessary-value-param,
   readability-*,
   -readability-avoid-nested-conditional-operator,
diff --git a/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp b/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp
index 789327b196ab6..d7b8f7bc62409 100644
--- a/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp
+++ b/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp
@@ -76,9 +76,9 @@ void StructPackAlignCheck::check(const MatchFinder::MatchResult &Result) {
   CharUnits CurrSize = Result.Context->getASTRecordLayout(Struct).getSize();
   CharUnits MinByteSize =
       CharUnits::fromQuantity(std::max<clang::CharUnits::QuantityType>(
-          ceil(static_cast<float>(TotalBitSize) / CharSize), 1));
+          std::ceil(static_cast<float>(TotalBitSize) / CharSize), 1));
   CharUnits MaxAlign = CharUnits::fromQuantity(
-      ceil((float)Struct->getMaxAlignment() / CharSize));
+      std::ceil((float)Struct->getMaxAlignment() / CharSize));
   CharUnits CurrAlign =
       Result.Context->getASTRecordLayout(Struct).getAlignment();
   CharUnits NewAlign = computeRecommendedAlignment(MinByteSize);
diff --git a/clang-tools-extra/clang-tidy/altera/UnrollLoopsCheck.cpp b/clang-tools-extra/clang-tidy/altera/UnrollLoopsCheck.cpp
index 0bb9d6e4a7cee..9846a573a8c29 100644
--- a/clang-tools-extra/clang-tidy/altera/UnrollLoopsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/altera/UnrollLoopsCheck.cpp
@@ -208,18 +208,20 @@ bool UnrollLoopsCheck::hasLargeNumIterations(const Stmt *Statement,
       return true;
     switch (Op->getOpcode()) {
     case (BO_AddAssign):
-      Iterations = ceil(float(EndValue - InitValue) / ConstantValue);
+      Iterations = std::ceil(float(EndValue - InitValue) / ConstantValue);
       break;
     case (BO_SubAssign):
-      Iterations = ceil(float(InitValue - EndValue) / ConstantValue);
+      Iterations = std::ceil(float(InitValue - EndValue) / ConstantValue);
       break;
     case (BO_MulAssign):
-      Iterations = 1 + (log((double)EndValue) - log((double)InitValue)) /
-                           log((double)ConstantValue);
+      Iterations =
+          1 + (std::log((double)EndValue) - std::log((double)InitValue)) /
+                  std::log((double)ConstantValue);
       break;
     case (BO_DivAssign):
-      Iterations = 1 + (log((double)InitValue) - log((double)EndValue)) /
-                           log((double)ConstantValue);
+      Iterations =
+          1 + (std::log((double)InitValue) - std::log((double)EndValue)) /
+                  std::log((double)ConstantValue);
       break;
     default:
       // All other operators are not handled; assume large bounds.