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| author | Hans-Peter Nilsson <hp@axis.com> | 2022-02-02 00:00:09 +0100 |
|---|---|---|
| committer | Hans-Peter Nilsson <hp@axis.com> | 2022-02-02 01:20:02 +0100 |
| commit | 4c4d0af4c94ccf0cfa74c8b13b8ec1029f57cd63 (patch) | |
| tree | 4faf5afcdf7342385ade8ff6f0f34120d4f78448 /gcc/config/cris | |
| parent | ae7e4af964eaa80a3d7c43e4a7e1864d9a7cb06b (diff) | |
| download | gcc-4c4d0af4c94ccf0cfa74c8b13b8ec1029f57cd63.zip gcc-4c4d0af4c94ccf0cfa74c8b13b8ec1029f57cd63.tar.gz gcc-4c4d0af4c94ccf0cfa74c8b13b8ec1029f57cd63.tar.bz2 | |
cris: Don't default to -mmul-bug-workaround
This flips the default for the errata handling for an old version
(TL;DR: workaround: no multiply instruction last on a cache-line).
Newer versions of the CRIS cpu don't have that bug. While the impact
of the workaround is very marginal (coremark: less than .05% larger,
less than .0005% slower) it's an irritating pseudorandom factor when
assessing the impact of other changes.
Also, fix a wart requiring changes to more than TARGET_DEFAULT to flip
the default.
People building old kernels or operating systems to run on
ETRAX 100 LX are advised to pass "-mmul-bug-workaround".
gcc:
* config/cris/cris.h (TARGET_DEFAULT): Don't include MASK_MUL_BUG.
(MUL_BUG_ASM_DEFAULT): New macro.
(MAYBE_AS_NO_MUL_BUG_ABORT): Define in terms of MUL_BUG_ASM_DEFAULT.
* doc/invoke.texi (CRIS Options, -mmul-bug-workaround): Adjust
accordingly.
Diffstat (limited to 'gcc/config/cris')
| -rw-r--r-- | gcc/config/cris/cris.h | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/gcc/config/cris/cris.h b/gcc/config/cris/cris.h index b274e11..9245d78 100644 --- a/gcc/config/cris/cris.h +++ b/gcc/config/cris/cris.h @@ -153,7 +153,9 @@ extern int cris_cpu_version; #ifdef HAVE_AS_NO_MUL_BUG_ABORT_OPTION #define MAYBE_AS_NO_MUL_BUG_ABORT \ - "%{mno-mul-bug-workaround:-no-mul-bug-abort} " + "%{mno-mul-bug-workaround:-no-mul-bug-abort} " \ + "%{mmul-bug-workaround:-mul-bug-abort} " \ + "%{!mmul-bug-workaround:%{!mno-mul-bug-workaround:" MUL_BUG_ASM_DEFAULT "}} " #else #define MAYBE_AS_NO_MUL_BUG_ABORT #endif @@ -255,15 +257,26 @@ extern int cris_cpu_version; (MASK_SIDE_EFFECT_PREFIXES + MASK_STACK_ALIGN \ + MASK_CONST_ALIGN + MASK_DATA_ALIGN \ + MASK_ALIGN_BY_32 \ - + MASK_PROLOGUE_EPILOGUE + MASK_MUL_BUG) + + MASK_PROLOGUE_EPILOGUE) # else /* 0 */ # define TARGET_DEFAULT \ (MASK_SIDE_EFFECT_PREFIXES + MASK_STACK_ALIGN \ + MASK_CONST_ALIGN + MASK_DATA_ALIGN \ - + MASK_PROLOGUE_EPILOGUE + MASK_MUL_BUG) + + MASK_PROLOGUE_EPILOGUE) # endif #endif +/* Don't depend on the assembler default setting for the errata machinery; + always pass the option to turn it on or off explicitly. But, we have to + decide on which is the *GCC* default, and for that we should only need to + consider what's in TARGET_DEFAULT; no other changes should be necessary. */ + +#if (TARGET_DEFAULT & MASK_MUL_BUG) +#define MUL_BUG_ASM_DEFAULT "-mul-bug-abort" +#else +#define MUL_BUG_ASM_DEFAULT "-no-mul-bug-abort" +#endif + /* Local, providing a default for cris_cpu_version. */ #define CRIS_DEFAULT_CPU_VERSION TARGET_CPU_DEFAULT |