On Thu, 14 Nov 2019, Matthew Malcomson wrote:
> Hi there,
>
> When compiling an __RTL function that has an invalid "startwith" pass we
> currently don't run the dfinish cleanup pass. This means we ICE on the next
> function.
>
> This change ensures that all state is cleaned up for the next function
> to run correctly.
>
> As an example, before this change the following code would ICE when compiling
> the function `foo2` because the "peephole2" pass is not run at optimisation
> level -O0.
>
> When compiled with
> ./aarch64-none-linux-gnu-gcc -O0 -S missed-pass-error.c -o test.s
>
> ```
> int __RTL (startwith ("peephole2")) badfoo ()
> {
> (function "badfoo"
> (insn-chain
> (block 2
> (edge-from entry (flags "FALLTHRU"))
> (cnote 3 [bb 2] NOTE_INSN_BASIC_BLOCK)
> (cinsn 101 (set (reg:DI x19) (reg:DI x0)))
> (cinsn 10 (use (reg/i:SI x19)))
> (edge-to exit (flags "FALLTHRU"))
> ) ;; block 2
> ) ;; insn-chain
> ) ;; function "foo2"
> }
>
> int __RTL (startwith ("final")) foo2 ()
> {
> (function "foo2"
> (insn-chain
> (block 2
> (edge-from entry (flags "FALLTHRU"))
> (cnote 3 [bb 2] NOTE_INSN_BASIC_BLOCK)
> (cinsn 101 (set (reg:DI x19) (reg:DI x0)))
> (cinsn 10 (use (reg/i:SI x19)))
> (edge-to exit (flags "FALLTHRU"))
> ) ;; block 2
> ) ;; insn-chain
> ) ;; function "foo2"
> }
> ```
>
> Now it silently ignores the __RTL function and successfully compiles foo2.
>
> regtest done on aarch64
> regtest done on x86_64
>
> OK for trunk?
OK.
Richard.
> gcc/ChangeLog:
>
> 2019-11-14 Matthew Malcomson <matthew.malcom...@arm.com>
>
> * passes.c (should_skip_pass_p): Always run "dfinish".
>
> gcc/testsuite/ChangeLog:
>
> 2019-11-14 Matthew Malcomson <matthew.malcom...@arm.com>
>
> * gcc.dg/rtl/aarch64/missed-pass-error.c: New test.
>
>
>
> ############### Attachment also inlined for ease of reply
> ###############
>
>
> diff --git a/gcc/passes.c b/gcc/passes.c
> index
> d86af115ecb16fcab6bfce070f1f3e4f1d90ce71..258f85ab4f8a1519b978b75dfa67536d2eacd106
> 100644
> --- a/gcc/passes.c
> +++ b/gcc/passes.c
> @@ -2375,7 +2375,8 @@ should_skip_pass_p (opt_pass *pass)
> return false;
>
> /* Don't skip df init; later RTL passes need it. */
> - if (strstr (pass->name, "dfinit") != NULL)
> + if (strstr (pass->name, "dfinit") != NULL
> + || strstr (pass->name, "dfinish") != NULL)
> return false;
>
> if (!quiet_flag)
> diff --git a/gcc/testsuite/gcc.dg/rtl/aarch64/missed-pass-error.c
> b/gcc/testsuite/gcc.dg/rtl/aarch64/missed-pass-error.c
> new file mode 100644
> index
> 0000000000000000000000000000000000000000..2f02ca9d0c40b372d86b24009540e157ed1a8c59
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/rtl/aarch64/missed-pass-error.c
> @@ -0,0 +1,45 @@
> +/* { dg-do compile { target aarch64-*-* } } */
> +/* { dg-additional-options "-O0" } */
> +
> +/*
> + When compiling __RTL functions the startwith string can be either
> incorrect
> + (i.e. not matching a pass) or be unused (i.e. can refer to a pass that is
> + not run at the current optimisation level).
> +
> + Here we ensure that the state clean up is still run, so that functions
> other
> + than the faulty one can still be compiled.
> + */
> +
> +int __RTL (startwith ("peephole2")) badfoo ()
> +{
> +(function "badfoo"
> + (insn-chain
> + (block 2
> + (edge-from entry (flags "FALLTHRU"))
> + (cnote 3 [bb 2] NOTE_INSN_BASIC_BLOCK)
> + (cinsn 101 (set (reg:DI x19) (reg:DI x0)))
> + (cinsn 10 (use (reg/i:SI x19)))
> + (edge-to exit (flags "FALLTHRU"))
> + ) ;; block 2
> + ) ;; insn-chain
> +) ;; function "foo2"
> +}
> +
> +/* Compile a valid __RTL function to test state from the "dfinit" pass has
> been
> + cleaned with the "dfinish" pass. */
> +
> +int __RTL (startwith ("final")) foo2 ()
> +{
> +(function "foo2"
> + (insn-chain
> + (block 2
> + (edge-from entry (flags "FALLTHRU"))
> + (cnote 3 [bb 2] NOTE_INSN_BASIC_BLOCK)
> + (cinsn 101 (set (reg:DI x19) (reg:DI x0)))
> + (cinsn 10 (use (reg/i:SI x19)))
> + (edge-to exit (flags "FALLTHRU"))
> + ) ;; block 2
> + ) ;; insn-chain
> +) ;; function "foo2"
> +}
> +
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
