Hi Richard,
Richard Sandiford <richard.sandif...@arm.com> wrote:
Iain Sandoe <i...@sandoe.co.uk> writes:
The armv8_arm manual [C6.2.226, ROR (immediate)] uses a # in front
of the immediate rotation quantity.
Although, it seems, GAS is able to infer the # (or is leninent about
its absence) assemblers based on the LLVM back end expect it and error
out.
tested on aarch64-linux-gnu (gcc115) and aarch64-darwin20 (experimental)
Sorry for the slow reply, didn't see this till now.
Hmm .. I did CC you directly ( but having some troubles with this ISP which
I am
trying to resolve - emails going missing or have to be re-sent … :/ )
The patch is OK in principle, and personally I prefer “#”. But how far
does this spread? Are only ROR modifiers on logical patterns affected?
Or is the use of a paranthesised expression instead of a literal the thing
that makes the difference?
perhaps,
Unfortunately, I have only a cause and effect mechanism to check this (i.e.
problems that prevent bootstrap or ones I’ve triaged in the testsuite fails).
For X86 and PPC I have a more direct way of invoking the LLVM backend (not
had
time to extend that to aarch64 yet).
.. but via XCode (which is what 99.99% of macOS folks will use as their
‘binutils’) it’s
done by “as” ==> "clang -cc1as” (effectively an assembler with
preprocessing). This
issue certainly fires there - and I’d have no reason to think that the
preprocessor would
make any material difference, so it’s likely that the LLVM backend is not
set up to
deduce that the value is a constant and infer the ‘#’.
GCC is generally quite lax at including “#”, so I'd expect more fallout
than this.
This is one of three issues (that are not directly related to mach-o format
or relocation
syntax) that I’ve encountered in my experimental port that happen to
trigger in bootstrap.
(the others are a format specifier type naming clash and one related to
Darwin having
signed chars by default - so this is the only asm syntax one remaining - Alex
fixed the
other fails earlier in the year).
Of course, it’s possible that there are other cases in the testsuite
fallout that i’ve not yet
examined - there’s quite a lot still to triage :(.
Once upon a time there were some tests (at least for PPC and X86) that
essentially
were a single file containing all the insns - so that could be thrown at an
assembler
and would be expected to complete without error - but I don’t know if
there’s an
equivalent for aarch64.
cheers
Iain
* I suppose someone could grep ‘#’ in the armv8_arm and c.f. cases against
aarch64.md
(I dare not volunteer, at present, since I’m already way overcomitted with
non-$dayjob).
Thanks,
Richard
OK for master?
thanks
Iain
gcc/ChangeLog:
* config/aarch64/aarch64.md (<optab>_rol<mode>3): Add a '#'
mark in front of the immediate quantity.
(<optab>_rolsi3_uxtw): Likewise.
---
gcc/config/aarch64/aarch64.md | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 45d9c6ac45a..e0de82c938a 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -4416,7 +4416,7 @@
(match_operand:QI 2 "aarch64_shift_imm_<mode>" "n"))
(match_operand:GPI 3 "register_operand" "r")))]
""
- "<logical>\\t%<w>0, %<w>3, %<w>1, ror (<sizen> - %2)"
+ "<logical>\\t%<w>0, %<w>3, %<w>1, ror #(<sizen> - %2)"
[(set_attr "type" "logic_shift_imm")]
)
@@ -4441,7 +4441,7 @@
(match_operand:QI 2 "aarch64_shift_imm_si" "n"))
(match_operand:SI 3 "register_operand" "r"))))]
""
- "<logical>\\t%w0, %w3, %w1, ror (32 - %2)"
+ "<logical>\\t%w0, %w3, %w1, ror #(32 - %2)"
[(set_attr "type" "logic_shift_imm")]
)
