[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594 Joseph changed: What|Removed |Added CC||schuchart at icl dot utk.edu --- Comment #10 from Joseph --- The lack of target-specific optimizations is biting us quite a bit and manually specifying an architecture is not really an option, unless we duplicate the detection mechanism of GCC, which is not ideal. I am not familiar with the GCC code base and from the discussion below it's not clear what would be needed to advance this. If someone could provide some hints on what is missing and how/where it could be implemented we could probably take a stab at it. Would it be sufficient to add a macro to the header of the targets (as suggested here https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594#c6) that provide host_detect_local_cpu and ignore the ones that do not provide it? Or would it be better to hard-code calls for the architectures that provide them, like in the referenced patch but with architecture-specific pre-processor guards? We mostly care about i386 and arm/aarch64 but covering all available bases would be necessary, I guess.
[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594 Andrew Pinski changed: What|Removed |Added CC||helohe at bluewin dot ch --- Comment #9 from Andrew Pinski --- *** Bug 107230 has been marked as a duplicate of this bug. ***
[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594 Eric Gallager changed: What|Removed |Added Status|NEW |ASSIGNED --- Comment #8 from Eric Gallager --- (In reply to Eric Gallager from comment #7) > Confirming as an enhancement ...actually making that ASSIGNED (instead of NEW) due to that fitting.
[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594 Eric Gallager changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2018-05-07 CC||egallager at gcc dot gnu.org Ever confirmed|0 |1 Severity|normal |enhancement --- Comment #7 from Eric Gallager --- Confirming as an enhancement
[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594 --- Comment #2 from David Malcolm dmalcolm at gcc dot gnu.org --- (In reply to Andrew Pinski from comment #1) This should be true on all targets which have -mcpu=native (or -march=native). Note x86 options are not always the same on x86 vs arm vs aarch64 vs ppc. Thanks. Is there a way to express give me the most specialized possible code for the current host? in a manner that's consistent across all supported hosts? (e.g. in the specs language?) e.g. -march=native -mcpu=native -mtune=native
[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594 --- Comment #5 from David Malcolm dmalcolm at gcc dot gnu.org --- Created attachment 35815 -- https://gcc.gnu.org/bugzilla/attachment.cgi?id=35815action=edit Hacky work-in-progress fix, using hardcoded calls to host_detect_local_cpu The attached patch is a hack, in that (A) it assumes host_detect_local_cpu exists, which isn't always the case, (B) it loops through arch, cpu, tune, trying all of them, and appending any results in order to libgccjit's fake args. ...but it seems to work on x86_64.
[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594
--- Comment #3 from David Malcolm dmalcolm at gcc dot gnu.org ---
Some notes:
The following archs seem to implement a host_detect_local_cpu C++ callback,
implementing the spec-language function local_cpu_detect:
grep -nH -e host_detect_local_cpu */*/*.h
config/aarch64/aarch64.h:944:extern const char *host_detect_local_cpu (int
argc, const char **argv);
config/aarch64/aarch64.h:946: { local_cpu_detect, host_detect_local_cpu },
\
config/alpha/linux.h:95:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/alpha/linux.h:97: { local_cpu_detect, host_detect_local_cpu },
config/arm/arm.h:2246:extern const char *host_detect_local_cpu (int argc, const
char **argv);
config/arm/arm.h:2248: { local_cpu_detect, host_detect_local_cpu },
\
config/i386/i386.h:604:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/i386/i386.h:606: { local_cpu_detect, host_detect_local_cpu },
config/mips/gnu-user.h:111:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/mips/gnu-user.h:113: { local_cpu_detect, host_detect_local_cpu },
config/rs6000/rs6000.h:204:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/rs6000/rs6000.h:206: { local_cpu_detect, host_detect_local_cpu },
config/s390/s390.h:129:extern const char *s390_host_detect_local_cpu (int argc,
const char **argv);
config/s390/s390.h:131: { local_cpu_detect, s390_host_detect_local_cpu },
config/sparc/linux64.h:133:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/sparc/linux64.h:135: { local_cpu_detect, host_detect_local_cpu },
config/sparc/linux.h:44:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/sparc/linux.h:46: { local_cpu_detect, host_detect_local_cpu },
config/sparc/sol2.h:203:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/sparc/sol2.h:205: { local_cpu_detect, host_detect_local_cpu },
aarch64.h has:
# define MCPU_MTUNE_NATIVE_SPECS\
%{march=native:%march=native %:local_cpu_detect(arch)} \
%{mcpu=native:%mcpu=native %:local_cpu_detect(cpu)} \
%{mtune=native:%mtune=native %:local_cpu_detect(tune)}
alpha/linux.h has:
# define MCPU_MTUNE_NATIVE_SPECS\
%{mcpu=native:%mcpu=native %:local_cpu_detect(cpu)} \
%{mtune=native:%mtune=native %:local_cpu_detect(tune)}
arm.h has:
# define MCPU_MTUNE_NATIVE_SPECS\
%{march=native:%march=native %:local_cpu_detect(arch)} \
%{mcpu=native:%mcpu=native %:local_cpu_detect(cpu)} \
%{mtune=native:%mtune=native %:local_cpu_detect(tune)}
i386.h has:
#ifndef HAVE_LOCAL_CPU_DETECT
#define CC1_CPU_SPEC CC1_CPU_SPEC_1
#else
#define CC1_CPU_SPEC CC1_CPU_SPEC_1 \
%{march=native:%march=native %:local_cpu_detect(arch) \
%{!mtune=*:%mtune=native %:local_cpu_detect(tune)}} \
%{mtune=native:%mtune=native %:local_cpu_detect(tune)}
#endif
#endif
mips/gnu-user.h has:
# define MARCH_MTUNE_NATIVE_SPECS \
%{march=native:%march=native %:local_cpu_detect(arch)}\
%{mtune=native:%mtune=native %:local_cpu_detect(tune)}
#define HAVE_LOCAL_CPU_DETECT
#define ASM_CPU_NATIVE_SPEC %:local_cpu_detect(asm)
#else
#define ASM_CPU_NATIVE_SPEC %(asm_default)
#endif
rs6000.h has:
#ifndef CC1_CPU_SPEC
#ifdef HAVE_LOCAL_CPU_DETECT
#define CC1_CPU_SPEC \
%{mcpu=native:%mcpu=native %:local_cpu_detect(cpu)} \
%{mtune=native:%mtune=native %:local_cpu_detect(tune)}
#else
#define CC1_CPU_SPEC
#endif
#endif
s390.h has:
# define MARCH_MTUNE_NATIVE_SPECS \
%{march=native:%march=native %:local_cpu_detect(arch)}\
%{mtune=native:%mtune=native %:local_cpu_detect(tune)}
sparc/linux64.h, sparc/linux.h and sparc/sol2.h have:
# define MCPU_MTUNE_NATIVE_SPECS\
%{mcpu=native:%mcpu=native %:local_cpu_detect(cpu)} \
%{mtune=native:%mtune=native %:local_cpu_detect(tune)}
[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594 --- Comment #4 from ktkachov at gcc dot gnu.org --- (In reply to David Malcolm from comment #2) (In reply to Andrew Pinski from comment #1) This should be true on all targets which have -mcpu=native (or -march=native). Note x86 options are not always the same on x86 vs arm vs aarch64 vs ppc. Thanks. Is there a way to express give me the most specialized possible code for the current host? in a manner that's consistent across all supported hosts? (e.g. in the specs language?) e.g. -march=native -mcpu=native -mtune=native A note that the meaning of march/mcpu/mtune may differ among targets. For arm and aarch64, for example, the preferred option is -mcpu, which is the combination of march+mtune
[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594 --- Comment #6 from David Malcolm dmalcolm at gcc dot gnu.org --- (In reply to ktkachov from comment #4) (In reply to David Malcolm from comment #2) (In reply to Andrew Pinski from comment #1) This should be true on all targets which have -mcpu=native (or -march=native). Note x86 options are not always the same on x86 vs arm vs aarch64 vs ppc. Thanks. Is there a way to express give me the most specialized possible code for the current host? in a manner that's consistent across all supported hosts? (e.g. in the specs language?) e.g. -march=native -mcpu=native -mtune=native A note that the meaning of march/mcpu/mtune may differ among targets. For arm and aarch64, for example, the preferred option is -mcpu, which is the combination of march+mtune Perhaps we need a target macro that's something like: TARGET_JIT_NATIVE_CODE_SPEC or somesuch, defaulting to empty, but defining it per-arch to a spec-language string containing the appropriate option(s) for that host/target? (assuming host==target, which is currently the case for the jit).
[Bug jit/66594] jitted code should use -mtune=native
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594 --- Comment #1 from Andrew Pinski pinskia at gcc dot gnu.org --- This should be true on all targets which have -mcpu=native (or -march=native). Note x86 options are not always the same on x86 vs arm vs aarch64 vs ppc.
