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divmod transform: add test-cases

Message ID CAAgBjMndkxzEryLy9yT=pNB7NMD+g0UdJ8go6=C_hvvTR5nN2Q@mail.gmail.com
State New
Headers show

Commit Message

Prathamesh Kulkarni Aug. 12, 2016, 12:04 p.m. UTC 
On 12 August 2016 at 12:47, Richard Biener <rguenther@suse.de> wrote:
> On Thu, 11 Aug 2016, Jeff Law wrote:

>

>> On 08/09/2016 04:58 AM, Prathamesh Kulkarni wrote:

>> > ping https://gcc.gnu.org/ml/gcc-patches/2016-07/msg01869.html

>> This seems to be dependent upon other patches, this is not OK until all

>> prereqs are resolved.

>>

>> You're using SI/DI in the descriptions, but then using more traditional C

>> types like int, unsigned, long long in the actual test.

>>

>> If you intent is really to nail down SI/DI mode testing, then the way to go

>> will be to define typedefs that correspond directly to SI and DI modes:

>>

>> typedef unsigned int u32 __attribute__((mode(SI)));

>> typedef signed int s32 __attribute__((mode(SI)));

>>

>> You can do something similar for DImode.

>>

>> It may not matter because of your effective-target {divmod,divmod_simode}

>> selectors, but it still seems cleaner.

>>

>> With that change, this is OK when its prereqs are resolved.

>

> Note that for the main patch I don't like the current state of the

> divmod libcall issue.  I think we need to solve this in a more

> reasonable manner and not expose this oddness to a GIMPLE level pass.

>

> Any ideas welcome - I don't have a very good one :/

>

> The best idea I have is to not lie about libfunc availability in

> the optab handler.

Hi,
In the attached patch I set libfunc entry for sdivmod_optab to NULL
and verified that optab_libfunc (sdivmod_optab, DImode) returns NULL_RTX
if it's not overriden by the target.

AFAIU this issue could be latent in expand_twoval_binop_libfunc,
and apparently never got triggered for the default case, where target
doesn't override
optab_libfunc (sdivmod_optab, DImode) else it could have generated
call to __divmoddi4() which doesn't exist

Bootstrapped and tested on ppc64le-linux-gnu,
Cross-tested on arm*-*-*, aarch64*-*-*.
Bootstrap+test in progress on x86_64-unknown-linux-gnu.

OK to commit if passes ?

Thanks,
Prathamesh
>

> Richard.
diff mbox

Patch

diff --git a/gcc/optabs.def b/gcc/optabs.def
index 8875e30..305f8c0 100644
--- a/gcc/optabs.def
+++ b/gcc/optabs.def
@@ -116,7 +116,7 @@  OPTAB_NL(ssdiv_optab, "ssdiv$Q$a3", SS_DIV, "ssdiv", '3', gen_signed_fixed_libfu
 OPTAB_NL(udiv_optab, "udiv$I$a3", UDIV, "udiv", '3', gen_int_unsigned_fixed_libfunc)
 OPTAB_NX(udiv_optab, "udiv$Q$a3")
 OPTAB_NL(usdiv_optab, "usdiv$Q$a3", US_DIV, "usdiv", '3', gen_unsigned_fixed_libfunc)
-OPTAB_NL(sdivmod_optab, "divmod$a4", UNKNOWN, "divmod", '4', gen_int_libfunc)
+OPTAB_NL(sdivmod_optab, "divmod$a4", UNKNOWN, "divmod", '4', NULL) 
 OPTAB_NL(udivmod_optab, "udivmod$a4", UNKNOWN, "udivmod", '4', gen_int_libfunc)
 OPTAB_NL(smod_optab, "mod$a3", MOD, "mod", '3', gen_int_libfunc)
 OPTAB_NL(umod_optab, "umod$a3", UMOD, "umod", '3', gen_int_libfunc)