On Mon, 16 Nov 2020, Jakub Jelinek wrote:
> Hi!
>
> The test has been added 3 years before noipa attribute has been introduced,
> but already at that point I wanted to avoid IPA opts getting into way,
> most of the foo function is optimized away and the debug info just points
> to the caller\s var. With the recent modref/aliasing changes the caller's
> store to the variable whose address it is passing to the function is
> optimized away too.
>
> I think we should just use noipa to avoid this, though perhaps longer term
> we should think about some debug info improvements how to deal with that.
>
> The caller had before dse1:
> # DEBUG BEGIN_STMT
> x.f = 5.0e+0;
> x.g = 6.0e+0;
> # DEBUG BEGIN_STMT
> foo (&x);
> # DEBUG BEGIN_STMT
> x ={v} {CLOBBER};
> and the x.f and x.g stores are optimized away. If we had a way to pretend
> the memory contains those values anyway...
Yeah, but as Alex always said all his stuff isn't designed to fix
debug info of in-memory vars. IIRC Richard Sandiford had some patches
to try to deal with DSE eliding those [for -Og]. I guess one of the
issues will be on the consumer side where printing x.g might give
6.0e+0 but printing *(double *)0xtheaddress will very likely not
(because the memory does _not_ contain the value).
> Tested on x86_64-linux, fixes the guality regressions
OK.
> +FAIL: gcc.dg/guality/pr59776.c -O1 -DPREVENT_OPTIMIZATION line
> pr59776.c:17 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O1 -DPREVENT_OPTIMIZATION line
> pr59776.c:17 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O1 -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O1 -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O1 -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s2.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -DPREVENT_OPTIMIZATION line
> pr59776.c:17 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -DPREVENT_OPTIMIZATION line
> pr59776.c:17 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s2.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fno-use-linker-plugin
> -flto-partition=none -DPREVENT_OPTIMIZATION line pr59776.c:17 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fno-use-linker-plugin
> -flto-partition=none -DPREVENT_OPTIMIZATION line pr59776.c:17 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fno-use-linker-plugin
> -flto-partition=none -DPREVENT_OPTIMIZATION line pr59776.c:20 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fno-use-linker-plugin
> -flto-partition=none -DPREVENT_OPTIMIZATION line pr59776.c:20 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fno-use-linker-plugin
> -flto-partition=none -DPREVENT_OPTIMIZATION line pr59776.c:20 s2.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fuse-linker-plugin
> -fno-fat-lto-objects -DPREVENT_OPTIMIZATION line pr59776.c:17 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fuse-linker-plugin
> -fno-fat-lto-objects -DPREVENT_OPTIMIZATION line pr59776.c:17 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fuse-linker-plugin
> -fno-fat-lto-objects -DPREVENT_OPTIMIZATION line pr59776.c:20 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fuse-linker-plugin
> -fno-fat-lto-objects -DPREVENT_OPTIMIZATION line pr59776.c:20 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O2 -flto -fuse-linker-plugin
> -fno-fat-lto-objects -DPREVENT_OPTIMIZATION line pr59776.c:20 s2.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O3 -g -DPREVENT_OPTIMIZATION line
> pr59776.c:17 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O3 -g -DPREVENT_OPTIMIZATION line
> pr59776.c:17 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O3 -g -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -O3 -g -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -O3 -g -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s2.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -Os -DPREVENT_OPTIMIZATION line
> pr59776.c:17 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -Os -DPREVENT_OPTIMIZATION line
> pr59776.c:17 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -Os -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s1.f == 5.0
> +FAIL: gcc.dg/guality/pr59776.c -Os -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s1.g == 6.0
> +FAIL: gcc.dg/guality/pr59776.c -Os -DPREVENT_OPTIMIZATION line
> pr59776.c:20 s2.f == 5.0
> introduced in the last 2 days.
>
> 2020-11-16 Jakub Jelinek <ja...@redhat.com>
>
> * gcc.dg/guality/pr59776.c (foo): Use noipa attribute instead of
> noinline, noclone.
>
> --- gcc/testsuite/gcc.dg/guality/pr59776.c.jj 2020-01-29 22:59:09.181316689
> +0100
> +++ gcc/testsuite/gcc.dg/guality/pr59776.c 2020-11-16 22:06:27.021813335
> +0100
> @@ -6,7 +6,7 @@
>
> struct S { float f, g; };
>
> -__attribute__((noinline, noclone)) void
> +__attribute__((noipa)) void
> foo (struct S *p)
> {
> struct S s1, s2; /* { dg-final { gdb-test pr59776.c:17
> "s1.f" "5.0" } } */
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imend
