Explicitly say that bitwise shifts for narrow types work similar to element-wise C shifts with integer promotions, which coincides with OpenCL semantics.
gcc/ChangeLog: * doc/extend.texi (Vector Extensions): Clarify bitwise shift semantics. --- gcc/doc/extend.texi | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index e426a2eb7d..6b4e94b6a1 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -12026,7 +12026,12 @@ elements in the operand. It is possible to use shifting operators @code{<<}, @code{>>} on integer-type vectors. The operation is defined as following: @code{@{a0, a1, @dots{}, an@} >> @{b0, b1, @dots{}, bn@} == @{a0 >> b0, a1 >> b1, -@dots{}, an >> bn@}}@. Vector operands must have the same number of +@dots{}, an >> bn@}}@. When the base type is narrower than @code{int}, +element-wise shifts are performed as if operands underwent C integer +promotions, like in OpenCL. This makes vector shifts by up to 31 bits +well-defined for vectors with @code{char} and @code{short} base types. + +Operands of binary vector operations must have the same number of elements. For convenience, it is allowed to use a binary vector operation -- 2.39.2