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.
---
gcc/doc/tm.texi | 5 +++++
gcc/target.def | 7 ++++++-
gcc/targhooks.c | 7 +++++++
gcc/targhooks.h | 1 +
4 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 15b0ab8..f36e376 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -11959,6 +11959,11 @@ 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 d598067..5599eb4 100644
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -4206,7 +4206,12 @@ 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 06de1e3..62051a9 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 74ffe5f..b716b97 100644
--- a/gcc/targhooks.h
+++ b/gcc/targhooks.h
@@ -286,6 +286,7 @@ 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 */
