[PATCH] invoke: RISC-V's -march doesn't take ISA strings

[Palmer Dabbelt <palmer@rivosinc.com>]

The docs say we take ISA strings, but that's never really been the case:
at a bare minimum we've required lower case strings, but there's
generally been some subtle differences as well in things like version
handling and such.  We talked about removing the lower case requirement
in the last GNU toolchain meeting and we've always called other
differences just bugs.  We don't have profile support yet, but based on
the discussions on the RISC-V lists it looks like we're going to have
some differences there as well.

So let's just stop pretending these are ISA strings.  That's been a
headache for years now, if we're meant to just be ISA-string-like here
then we don't have to worry about all these long-tail ISA string parsing
issues.

Link: https://lists.riscv.org/g/sig-toolchains/message/486

gcc/ChangeLog

	doc/invoke.texi (RISC-V): -march doesn't take ISA strings.

---

This is now woefully under-documented, as we can't even fall back on the
"it's just an ISA string" excuse any more.  I'm happy to go document
that, but figured I'd just send this along now so we can have the
discussion.
---
 gcc/doc/invoke.texi | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 94a2e20cfc1..780b0364c52 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -28617,11 +28617,11 @@ Produce code conforming to version 20191213.
 The default is @option{-misa-spec=20191213} unless GCC has been configured
 with @option{--with-isa-spec=} specifying a different default version.
 
-@item -march=@var{ISA-string}
+@item -march=@var{target-string}
 @opindex march
-Generate code for given RISC-V ISA (e.g.@: @samp{rv64im}).  ISA strings must be
-lower-case.  Examples include @samp{rv64i}, @samp{rv32g}, @samp{rv32e}, and
-@samp{rv32imaf}.
+Generate code for given target (e.g.@: @samp{rv64im}).  Target strings are
+similar to ISA strings, but must be lower-case.  Examples include @samp{rv64i},
+@samp{rv32g}, @samp{rv32e}, and @samp{rv32imaf}.
 
 When @option{-march=} is not specified, use the setting from @option{-mcpu}.
 
-- 
2.38.1