[libc] Fix small bugs in aarch64/FEnvImpl.h and simplify feclearexcept_test.

[lntue]

Summary

Fix small bugs in aarch64/EFnvImpl.h and simplify feclearexcept_test.

[sivachandra]

libc/test/src/fenv/feclearexcept_test.cpp

67

Why did you remove these?

[lntue]

libc/test/src/fenv/feclearexcept_test.cpp

67

These tests are actually covered by the test below. For example, a single one exception is covered when e1 == e2 == e3 == e4 == e5, and so on.

libc/src/__support/FPUtil/aarch64/FEnvImpl.h

 static inline int test_except(int excepts) {
   uint32_t toTest = FEnv::getStatusValueForExcept(excepts);
   uint32_t statusWord = FEnv::getStatusWord();
   return FEnv::exceptionStatusToMacro(
       (statusWord >> FEnv::ExceptionStatusFlagsBitPosition) & toTest);
 }
 
 static inline int set_except(int excepts) {
-  uint32_t statusWord = FEnv::getControlWord();
+  uint32_t statusWord = FEnv::getStatusWord();
   uint32_t statusValue = FEnv::getStatusValueForExcept(excepts);
   statusWord |= (statusValue << FEnv::ExceptionStatusFlagsBitPosition);
   FEnv::writeStatusWord(statusWord);
   return 0;
 }
 
 static inline int raise_except(int excepts) {
   float zero = 0.0f;
   float one = 1.0f;
   float largeValue = float(FPBits<float>(FPBits<float>::MAX_NORMAL));
   float smallValue = float(FPBits<float>(FPBits<float>::MIN_NORMAL));
   auto divfunc = [](float a, float b) {
     __asm__ __volatile__("ldr  s0, %0\n\t"
                          "ldr  s1, %1\n\t"
                          "fdiv s0, s0, s1\n\t"
                          : // No outputs
                          : "m"(a), "m"(b)
                          : "s0", "s1" /* s0 and s1 are clobbered */);
   };
 
   uint32_t toRaise = FEnv::getStatusValueForExcept(excepts);
+  int result = 0;
 
   if (toRaise & FEnv::INVALID) {
     divfunc(zero, zero);
     uint32_t statusWord = FEnv::getStatusWord();
     if (!((statusWord >> FEnv::ExceptionStatusFlagsBitPosition) &
           FEnv::INVALID))
-      return -1;
+      result = -1;
   }
 
   if (toRaise & FEnv::DIVBYZERO) {
     divfunc(one, zero);
     uint32_t statusWord = FEnv::getStatusWord();
     if (!((statusWord >> FEnv::ExceptionStatusFlagsBitPosition) &
           FEnv::DIVBYZERO))
-      return -1;
+      result = -1;
   }
   if (toRaise & FEnv::OVERFLOW) {
     divfunc(largeValue, smallValue);
     uint32_t statusWord = FEnv::getStatusWord();
     if (!((statusWord >> FEnv::ExceptionStatusFlagsBitPosition) &
           FEnv::OVERFLOW))
-      return -1;
+      result = -1;
   }
   if (toRaise & FEnv::UNDERFLOW) {
     divfunc(smallValue, largeValue);
     uint32_t statusWord = FEnv::getStatusWord();
     if (!((statusWord >> FEnv::ExceptionStatusFlagsBitPosition) &
           FEnv::UNDERFLOW))
-      return -1;
+      result = -1;
   }
   if (toRaise & FEnv::INEXACT) {
     float two = 2.0f;
     float three = 3.0f;
     // 2.0 / 3.0 cannot be represented exactly in any radix 2 floating point
     // format.
     divfunc(two, three);
     uint32_t statusWord = FEnv::getStatusWord();
     if (!((statusWord >> FEnv::ExceptionStatusFlagsBitPosition) &
           FEnv::INEXACT))
-      return -1;
+      result = -1;
   }
-  return 0;
+  return result;
 }
 
 static inline int get_round() {
   uint32_t roundingMode =
       (FEnv::getControlWord() >> FEnv::RoundingControlBitPosition) & 0x3;
   switch (roundingMode) {
   case FEnv::TONEAREST:
     return FE_TONEAREST;

libc/test/src/fenv/feclearexcept_test.cpp

uint16_t excepts[] = {FE_DIVBYZERO, FE_INVALID, FE_INEXACT, FE_OVERFLOW,
                         FE_UNDERFLOW};
   __llvm_libc::fputil::disable_except(FE_ALL_EXCEPT);
   __llvm_libc::fputil::clear_except(FE_ALL_EXCEPT);
 
   for (uint16_t e : excepts)
     ASSERT_EQ(__llvm_libc::fputil::test_except(e), 0);
 
   __llvm_libc::fputil::raise_except(FE_ALL_EXCEPT);
-  for (uint16_t e : excepts) {
-    // We clear one exception and test to verify that it was cleared.
-    __llvm_libc::feclearexcept(e);
-    ASSERT_EQ(uint16_t(__llvm_libc::fputil::test_except(FE_ALL_EXCEPT)),
-              uint16_t(FE_ALL_EXCEPT & ~e));
-    // After clearing, we raise the exception again.
-    __llvm_libc::fputil::raise_except(e);
-  }
-
-  for (uint16_t e1 : excepts) {
-    for (uint16_t e2 : excepts) {
-      __llvm_libc::feclearexcept(e1 | e2);
-      ASSERT_EQ(uint16_t(__llvm_libc::fputil::test_except(FE_ALL_EXCEPT)),
-                uint16_t(FE_ALL_EXCEPT & ~(e1 | e2)));
-      __llvm_libc::fputil::raise_except(e1 | e2);
-    }
-  }
-
-  for (uint16_t e1 : excepts) {
-    for (uint16_t e2 : excepts) {
-      for (uint16_t e3 : excepts) {
-        __llvm_libc::feclearexcept(e1 | e2 | e3);
-        ASSERT_EQ(uint16_t(__llvm_libc::fputil::test_except(FE_ALL_EXCEPT)),
-                  uint16_t(FE_ALL_EXCEPT & ~(e1 | e2 | e3)));
-        __llvm_libc::fputil::raise_except(e1 | e2 | e3);
-      }
-    }
-  }
-
-  for (uint16_t e1 : excepts) {
-    for (uint16_t e2 : excepts) {
-      for (uint16_t e3 : excepts) {
-        for (uint16_t e4 : excepts) {
-          __llvm_libc::feclearexcept(e1 | e2 | e3 | e4);
-          ASSERT_EQ(uint16_t(__llvm_libc::fputil::test_except(FE_ALL_EXCEPT)),
-                    uint16_t(FE_ALL_EXCEPT & ~(e1 | e2 | e3 | e4)));
-          __llvm_libc::fputil::raise_except(e1 | e2 | e3 | e4);
-        }
-      }
-    }
-  }
 
   for (uint16_t e1 : excepts) {
     for (uint16_t e2 : excepts) {
       for (uint16_t e3 : excepts) {
         for (uint16_t e4 : excepts) {
           for (uint16_t e5 : excepts) {
+            // We clear one exception and test to verify that it was cleared.
             __llvm_libc::feclearexcept(e1 | e2 | e3 | e4 | e5);
-            ASSERT_EQ(uint16_t(__llvm_libc::fputil::test_except(FE_ALL_EXCEPT)),
-                      uint16_t(FE_ALL_EXCEPT & ~(e1 | e2 | e3 | e4 | e5)));
+            ASSERT_EQ(__llvm_libc::fputil::test_except(e1 | e2 | e3 | e4 | e5),
+                      0);
+            // After clearing, we raise the exception again.
             __llvm_libc::fputil::raise_except(e1 | e2 | e3 | e4 | e5);
           }
         }
       }
     }
   }
 }