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The result of E1 << E2 is E1 left-shifted E2 bit positions; vacated bits are filled with zeros. If E1 has a signed type and nonnegative value, and E1 * 2E2 is representable in the result type, then that is the resulting value; otherwise, the behavior is undefined (See undefined behavior 48.).

This noncompliant code example fails to ensure that left and right operands have nonnegative values and that the right operand is less than the precision of the promoted left operand. This example does check for signed integer overflow in compliance with INT32-C. Ensure that operations on signed integers do not result in overflow.

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This noncompliant code example fails to test whether the right operand is greater than or equal to the precision of the promoted left operand, allowing undefined behavior (See undefined behavior 48.):

void func(unsigned int ui_a, unsigned int ui_b) {
  unsigned int uresult = ui_a >> ui_b;
  /* ... */
}

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