#1 don't divide or multiply with 1

pauldreik · May 27, 2019 · ccacbd1 · ccacbd1
1 parent 6248d08
commit ccacbd1
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Showing 3 changed files with 47 additions and 67 deletions.
diff --git a/build.sh b/build.sh
@@ -8,8 +8,6 @@ set -e
 root=$(readlink -f $(dirname "$0"))
 me=$(basename $0)
 
-stds="11 1y 1z 2a"
-
 # $1 - name
 # $2...  passed to cmake
 dobuild() {
@@ -30,62 +28,36 @@ fi
 export CXX
 export CXXFLAGS	
 
-#make a sanitizers debug build with the default compiler, C++17
+#make a full sanitizers debug build with the default compiler, C++17
 CXXFLAGS="-fsanitize=undefined,address -g -O0 -std=c++1z -Wall -Wextra"
 dobuild sanitizers_17 \
 -DBUILD_EXAMPLES=On \
--DBUILD_FUZZERS=Off \
 -DBUILD_UNITTESTS=On \
 -DBUILD_EXHAUSTIVE_TESTS=On \
--DCMAKE_BUILD_TYPE=Debug \
--DFUZZ_LINKMAIN=On
+-DCMAKE_BUILD_TYPE=Debug 
 
 #make sure the examples can be built with c++11
 CXXFLAGS="-g -O0 -std=c++11 -Wall -Wextra"
 dobuild normal_cpp11 \
 -DBUILD_EXAMPLES=On \
--DBUILD_FUZZERS=Off \
 -DBUILD_UNITTESTS=Off \
--DCMAKE_BUILD_TYPE=Debug \
--DFUZZ_LINKMAIN=On
+-DCMAKE_BUILD_TYPE=Debug
 
 #make a libfuzzer build with sanitizers
 CXX=clang++
 CXXFLAGS="-fsanitize=fuzzer-no-link,undefined,address -g -O0 -std=c++1z"
 dobuild libfuzzer_with_sanitizers \
--DBUILD_EXAMPLES=Off \
 -DBUILD_FUZZERS=On \
--DBUILD_UNITTESTS=Off \
 -DCMAKE_BUILD_TYPE=Debug \
 -DFUZZ_LINKMAIN=Off \
 -DFUZZ_LDFLAGS=-fsanitize=fuzzer
 
 #make a speed measurement build
 CXXFLAGS="-std=c++1z -Wall -Wextra"
 dobuild speedtest \
--DBUILD_EXAMPLES=Off \
--DBUILD_FUZZERS=Off \
--DBUILD_UNITTESTS=Off \
 -DBUILD_SPEED_TESTS=On \
--DBUILD_EXHAUSTIVE_TESTS=Off \
--DCMAKE_BUILD_TYPE=Release \
--DFUZZ_LINKMAIN=On
+-DBUILD_EXHAUSTIVE_TESTS=On \
+-DCMAKE_BUILD_TYPE=Release
 
 echo $me: all tests passed
-exit 0
-
-mkdir "$root/build-sanitizers"
-cd "$root/build-sanitizers"
-CXX=clang++ CXXFLAGS="-fsanitize=undefined,address -g -O0" \
-cmake $root -DBUILD_EXAMPLES=On -DBUILD_FUZZERS=Off -DBUILD_UNITTESTS=On \
--DCMAKE_BUILD_TYPE=Debug -DFUZZ_LINKMAIN=On -GNinja
-ninja
-
-#make a fuzzer build
-mkdir "$root/build-libfuzzer"
-cd "$root/build-libfuzzer"
-CXX=clang++ CXXFLAGS="-fsanitize=fuzzer-no-link,undefined,address" \
-cmake $root -DBUILD_EXAMPLES=Off -DBUILD_FUZZERS=On -DBUILD_UNITTESTS=Off \
--DCMAKE_BUILD_TYPE=Debug -DFUZZ_LINKMAIN=Off -GNinja -DFUZZ_LDFLAGS=-fsanitize=fuzzer
-ninja
 
diff --git a/include/detail/chronoconv_detail.hpp b/include/detail/chronoconv_detail.hpp
@@ -113,22 +113,27 @@ safe_duration_cast_dispatch(From from, int& ec, tags::FromIsInt, tags::ToIsInt)
     return {};
   }
   // multiply with Factor::num without overflow or underflow
-  constexpr auto max1 =
-    std::numeric_limits<IntermediateRep>::max() / Factor::num;
-  if (count > max1) {
-    ec = 1;
-    return {};
-  }
-  constexpr auto min1 =
-    std::numeric_limits<IntermediateRep>::min() / Factor::num;
-  if (count < min1) {
-    ec = 1;
-    return {};
-  }
-  count *= Factor::num;
+  if
+    SDC_CONSTEXPR_IF(Factor::num != 1)
+    {
+      constexpr auto max1 =
+        std::numeric_limits<IntermediateRep>::max() / Factor::num;
+      if (count > max1) {
+        ec = 1;
+        return {};
+      }
+      constexpr auto min1 =
+        std::numeric_limits<IntermediateRep>::min() / Factor::num;
+      if (count < min1) {
+        ec = 1;
+        return {};
+      }
+      count *= Factor::num;
+    }
 
   // this can't go wrong, right? den>0 is checked earlier.
-  count /= Factor::den;
+  if
+    SDC_CONSTEXPR_IF(Factor::den != 1) { count /= Factor::den; }
   // convert to the to type, safely
   using ToRep = typename To::rep;
   const ToRep tocount = lossless_integral_conversion<ToRep>(count, ec);
@@ -212,23 +217,29 @@ safe_duration_cast_dispatch(From from,
     convert_and_check_cfenv<IntermediateRep>(from.count());
 
   // multiply with Factor::num without overflow or underflow
-  constexpr auto max1 =
-    std::numeric_limits<IntermediateRep>::max() / Factor::num;
-  if (count > max1) {
-    ec = 1;
-    return {};
-  }
-  constexpr auto min1 =
-    std::numeric_limits<IntermediateRep>::lowest() / Factor::num;
-  if (count < min1) {
-    ec = 1;
-    return {};
-  }
-  count *= Factor::num;
-  assert(std::fetestexcept(FE_INVALID) == 0);
+  if
+    SDC_CONSTEXPR_IF(Factor::num != 1)
+    {
+      constexpr auto max1 =
+        std::numeric_limits<IntermediateRep>::max() / Factor::num;
+      if (count > max1) {
+        ec = 1;
+        return {};
+      }
+      constexpr auto min1 =
+        std::numeric_limits<IntermediateRep>::lowest() / Factor::num;
+      if (count < min1) {
+        ec = 1;
+        return {};
+      }
+      count *= Factor::num;
+      assert(std::fetestexcept(FE_INVALID) == 0);
+    }
 
   // this can't go wrong, right? den>0 is checked earlier.
-  count /= Factor::den;
+  if
+    SDC_CONSTEXPR_IF(Factor::den != 1) { count /= Factor::den; }
+
   // convert to the to type, safely
   using ToRep = typename To::rep;
 

diff --git a/tests/chronoconv_floating_test.cpp b/tests/chronoconv_floating_test.cpp
@@ -128,8 +128,6 @@ TEST_CASE("long double overflow/underflow should be noticed")
   verifyInternalOverflow(std::numeric_limits<long double>::lowest() / 2);
 }
 
-
-
 /*
  *  make sure the largest finite values are preserved
  */
@@ -139,10 +137,9 @@ verifyIdentity(Rep val)
 {
   using D = std::chrono::duration<Rep>;
   int err;
-  const auto to =
-    safe_duration_cast::safe_duration_cast<D>(D{ val }, err);
+  const auto to = safe_duration_cast::safe_duration_cast<D>(D{ val }, err);
   REQUIRE(err == 0);
-  REQUIRE(to.count()==val);
+  REQUIRE(to.count() == val);
 }
 TEST_CASE("float limits should be preserved")
 {