On 6/26/24 08:50, Andrea Parri wrote:
Tested using amo.exp with rv64gc_zalrsc, rv64id_zaamo, rv64id_zalrsc,
rv64id_zabha (using tip-of-tree qemu w/ zabha patches [2] applied for
execution tests).
My interpretation of the Zabha specification, in particular of "The Zabha
extension depends upon the Zaamo standard extension", is that rv64id_zabha
should result in a dependency violation (some compiler warning).
The changes at stake seem instead to make the Zabha extension "select" the
Zaamo extension; IOW, these changes seem to make rv64id_zabha an alias of
rv64id_zaamo_zabha: I am wondering whether this was intentional?
Hi Andrea,
Thanks for highlighting this.
This is intentional - my understanding is that GCC adds extensions if
the specified extensions depend upon them.
For example in the Zvfh spec: "The Zvfh extension depends on the Zve32f
and Zfhmin extensions."
In riscv_implied_info zve32f and zfhmin are implied by zvfh: {"zvfh",
"zve32f"}, {"zvfh", "zfhmin"}
This can be seen here: https://godbolt.org/z/63518Wrcj in the .attribute
arch string: ...zfhmin1p0_zve32f1p0_...
Side tangent: oddly enough it looks like zvfh does not require/imply the
v extension?
Patrick
Andrea
