[PATCH v2 3/7] Add func to check if register is clobbered by clobber_high
Alan Hayward
alan.hayward@arm.com
Thu Jul 26 09:14:00 GMT 2018
Given a CLOBBER_HIGH expression and a register, it checks if
the register will be clobbered.
A second version exists for the cases where the expressions are
not available.
The function will be used throughout the following patches.
2018-07-25 Alan Hayward <alan.hayward@arm.com>
* rtl.h (reg_is_clobbered_by_clobber_high): Add declarations.
* rtlanal.c (reg_is_clobbered_by_clobber_high): Add function.
---
gcc/rtl.h | 10 ++++++++++
gcc/rtlanal.c | 29 +++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/gcc/rtl.h b/gcc/rtl.h
index f42d749511d..d549b0aad0b 100644
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -3467,6 +3467,16 @@ extern bool tablejump_p (const rtx_insn *, rtx_insn **, rtx_jump_table_data **);
extern int computed_jump_p (const rtx_insn *);
extern bool tls_referenced_p (const_rtx);
extern bool contains_mem_rtx_p (rtx x);
+extern bool reg_is_clobbered_by_clobber_high (unsigned int, machine_mode,
+ const_rtx);
+
+/* Convenient wrapper for reg_is_clobbered_by_clobber_high. */
+inline bool
+reg_is_clobbered_by_clobber_high (const_rtx x, const_rtx clobber_high_op)
+{
+ return reg_is_clobbered_by_clobber_high (REGNO (x), GET_MODE (x),
+ clobber_high_op);
+}
/* Overload for refers_to_regno_p for checking a single register. */
inline bool
diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index 9f84d7f2a8c..1cab1545744 100644
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -6551,3 +6551,32 @@ tls_referenced_p (const_rtx x)
return true;
return false;
}
+
+/* Return true if reg REGNO with mode REG_MODE would be clobbered by the
+ clobber_high operand in CLOBBER_HIGH_OP. */
+
+bool
+reg_is_clobbered_by_clobber_high (unsigned int regno, machine_mode reg_mode,
+ const_rtx clobber_high_op)
+{
+ unsigned int clobber_regno = REGNO (clobber_high_op);
+ machine_mode clobber_mode = GET_MODE (clobber_high_op);
+ unsigned char regno_nregs = hard_regno_nregs (regno, reg_mode);
+
+ /* Clobber high should always span exactly one register. */
+ gcc_assert (REG_NREGS (clobber_high_op) == 1);
+
+ /* Clobber high needs to match with one of the registers in X. */
+ if (clobber_regno < regno || clobber_regno >= regno + regno_nregs)
+ return false;
+
+ gcc_assert (reg_mode != BLKmode && clobber_mode != BLKmode);
+
+ if (reg_mode == VOIDmode)
+ return clobber_mode != VOIDmode;
+
+ /* Clobber high will clobber if its size might be greater than the size of
+ register regno. */
+ return maybe_gt (exact_div (GET_MODE_SIZE (reg_mode), regno_nregs),
+ GET_MODE_SIZE (clobber_mode));
+}
--
2.15.2 (Apple Git-101.1)
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