Hi,
On Mon, Feb 01, 2021 at 11:24:42PM -0500, Michael Meissner wrote:
> In PR target/98519, the assembler does not like asm memory references that are
> prefixed. We can't automatically change the instruction to prefixed form with
> a 'p' like we do for normal RTL insns, since this is assembly code.
It is incorrect in general, too, for at least three reasons.
> Instead,
> the patch prevents prefixed memory addresses from being passed by default.
>
> This patch uses the TARGET_MD_ASM_ADJUST target hook to change the 'm' and 'o'
> constraints to be 'em' and 'eo'.
This does not work correctly, and is a gross misuse of this hook anyway.
Like I said before, just make 'm' (or even general_operand) not allow
prefixed memory in inline asm.
> + while ((ch = *constraint++) != '\0')
Don't do assignments (or any other surprising side effects) in
conditionals please. Code should be *readable*, not a puzzle.
0 is written as 0, not as 000 or '\0' or 0x0 or anything else.
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr98519.c
> @@ -0,0 +1,17 @@
> +/* { dg-do compile } */
This is the default.
> +/* { dg-require-effective-target powerpc_prefixed_addr } */
You do not want this line, you want to compile this *always*. You set
cpu=power10 anyway! Also, the test should work *without it*!
> +/* { dg-final { scan-assembler-not {\m[@]pcrel\M} } } */
You can just write @ instead of [@]. Putting \m immediately in front of
a non-letter (or \M immediately after) does not do anything, either.
Segher
