From f3debef33629f8e8a95b5ed0cb79296e7a0282df Mon Sep 17 00:00:00 2001 From: Richard Earnshaw Date: Tue, 31 Jul 2018 17:36:36 +0000 Subject: [PATCH] targhooks - provide an alternative hook for targets that never execute speculatively This hook adds an alternative implementation for the target hook TARGET_HAVE_SPECULATION_SAFE_VALUE; it can be used by targets that have no CPU implementations that execute code speculatively. All that is needed for such targets now is to add: #undef TARGET_HAVE_SPECULATION_SAFE_VALUE #define TARGET_HAVE_SPECULATION_SAFE_VALUE speculation_safe_value_not_needed. to where you have your other target hooks and you're done. gcc: * targhooks.h (speculation_safe_value_not_needed): New prototype. * targhooks.c (speculation_safe_value_not_needed): New function. * target.def (have_speculation_safe_value): Update documentation. * doc/tm.texi: Regenerated. From-SVN: r263175 --- gcc/ChangeLog | 7 +++++++ gcc/doc/tm.texi | 5 +++++ gcc/target.def | 7 ++++++- gcc/targhooks.c | 7 +++++++ gcc/targhooks.h | 1 + 5 files changed, 26 insertions(+), 1 deletion(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 48a2002cfd7..f6328f4d856 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2018-07-31 Richard Earnshaw + + * targhooks.h (speculation_safe_value_not_needed): New prototype. + * targhooks.c (speculation_safe_value_not_needed): New function. + * target.def (have_speculation_safe_value): Update documentation. + * doc/tm.texi: Regenerated. + 2018-07-31 Richard Earnshaw * config/aarch64/iterators.md (ALLI_TI): New iterator. diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi index 351f0b38b0e..a40f45ade07 100644 --- a/gcc/doc/tm.texi +++ b/gcc/doc/tm.texi @@ -11935,6 +11935,11 @@ This hook is used to determine the level of target support for a pattern named @code{speculation_barrier}. Else it returns true for the first case and whether the pattern is enabled for the current compilation for the second case. + + For targets that have no processors that can execute instructions + speculatively an alternative implemenation of this hook is available: + simply redefine this hook to @code{speculation_safe_value_not_needed} + along with your other target hooks. @end deftypefn @deftypefn {Target Hook} rtx TARGET_SPECULATION_SAFE_VALUE (machine_mode @var{mode}, rtx @var{result}, rtx @var{val}, rtx @var{failval}) diff --git a/gcc/target.def b/gcc/target.def index dc8d7deba2e..c570f3825a5 100644 --- a/gcc/target.def +++ b/gcc/target.def @@ -4166,7 +4166,12 @@ DEFHOOK The default implementation returns false if the target does not define\n\ a pattern named @code{speculation_barrier}. Else it returns true\n\ for the first case and whether the pattern is enabled for the current\n\ - compilation for the second case.", + compilation for the second case.\n\ + \n\ + For targets that have no processors that can execute instructions\n\ + speculatively an alternative implemenation of this hook is available:\n\ + simply redefine this hook to @code{speculation_safe_value_not_needed}\n\ + along with your other target hooks.", bool, (bool active), default_have_speculation_safe_value) DEFHOOK diff --git a/gcc/targhooks.c b/gcc/targhooks.c index 06de1e3fa86..62051a98e98 100644 --- a/gcc/targhooks.c +++ b/gcc/targhooks.c @@ -2324,6 +2324,13 @@ default_have_speculation_safe_value (bool active) return false; #endif } +/* Alternative implementation of TARGET_HAVE_SPECULATION_SAFE_VALUE + that can be used on targets that never have speculative execution. */ +bool +speculation_safe_value_not_needed (bool active) +{ + return !active; +} /* Default implementation of the speculation-safe-load builtin. This implementation simply copies val to result and generates a diff --git a/gcc/targhooks.h b/gcc/targhooks.h index ba53778d468..f92ca5ca997 100644 --- a/gcc/targhooks.h +++ b/gcc/targhooks.h @@ -282,6 +282,7 @@ extern void default_select_early_remat_modes (sbitmap); extern tree default_preferred_else_value (unsigned, tree, unsigned, tree *); extern bool default_have_speculation_safe_value (bool); +extern bool speculation_safe_value_not_needed (bool); extern rtx default_speculation_safe_value (machine_mode, rtx, rtx, rtx); #endif /* GCC_TARGHOOKS_H */ -- 2.30.2