chore: add gaurd for zero denominator

Author: krishna2803

libc/src/__support/fixed_point/CMakeLists.txt

@@ -16,6 +16,7 @@ add_header_library(
     .fx_rep
     libc.include.llvm-libc-macros.stdfix_macros
     libc.src.__support.macros.attributes
+    libc.src.__support.macros.null_check
     libc.src.__support.macros.optimization
     libc.src.__support.CPP.type_traits
     libc.src.__support.CPP.bit

libc/src/__support/fixed_point/fx_bits.h

@@ -15,6 +15,7 @@
 #include "src/__support/CPP/type_traits.h"
 #include "src/__support/macros/attributes.h"   // LIBC_INLINE
 #include "src/__support/macros/config.h"       // LIBC_NAMESPACE_DECL
+#include "src/__support/macros/null_check.h"   // LIBC_CRASH_ON_VALUE
 #include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
 #include "src/__support/math_extras.h"
 
@@ -209,11 +210,9 @@ idiv(T x, T y) {
   using FXRep = FXRep<T>;
   using CompType = typename FXRep::CompType;
 
-  if (y == FXRep::ZERO()) {
-    // If the value of the second operand of the / operator is zero, the
-    // behavior is undefined. Ref: ISO/IEC TR 18037:2008(E) p.g. 16
-    return static_cast<XType>(0);
-  }
+  // If the value of the second operand of the / operator is zero, the
+  // behavior is undefined. Ref: ISO/IEC TR 18037:2008(E) p.g. 16
+  LIBC_CRASH_ON_VALUE(y, FXRep::ZERO());
 
   CompType x_comp = static_cast<CompType>(FXBits(x).get_bits());
   CompType y_comp = static_cast<CompType>(FXBits(y).get_bits());

libc/src/__support/macros/null_check.h

@@ -19,10 +19,19 @@
     if (LIBC_UNLIKELY((ptr) == nullptr))                                       \
       __builtin_trap();                                                        \
   } while (0)
+#define LIBC_CRASH_ON_VALUE(var, value)                                        \
+  do {                                                                         \
+    if (LIBC_UNLIKELY((var) == (value)))                                       \
+      __builtin_trap();                                                        \
+  } while (0)
+
 #else
 #define LIBC_CRASH_ON_NULLPTR(ptr)                                             \
   do {                                                                         \
   } while (0)
+#define LIBC_CRASH_ON_VALUE(var, value)                                        \
+  do {                                                                         \
+  } while (0)
 #endif
 
 #endif // LLVM_LIBC_SRC___SUPPORT_MACROS_NULL_CHECK_H