@@ -2762,6 +2762,39 @@ memory_modified_in_insn_p (const_rtx mem, const_rtx insn)
return memory_modified;
}
+/* Return TRUE if the destination of a set is rtx identical to
+ ITEM. */
+static inline bool
+set_dest_equal_p (const_rtx set, const_rtx item)
+{
+ rtx dest = SET_DEST (set);
+ return rtx_equal_p (dest, item);
+}
+
+/* Like memory_modified_in_insn_p, but return TRUE if INSN will
+ *DEFINITELY* modify the memory contents of MEM. */
+bool
+memory_must_be_modified_in_insn_p (const_rtx mem, const_rtx insn)
+{
+ if (!INSN_P (insn))
+ return false;
+ insn = PATTERN (insn);
+ if (GET_CODE (insn) == SET)
+ return set_dest_equal_p (insn, mem);
+ else if (GET_CODE (insn) == PARALLEL)
+ {
+ int i;
+ for (i = 0; i < XVECLEN (insn, 0); i++)
+ {
+ rtx sub = XVECEXP (insn, 0, i);
+ if (GET_CODE (sub) == SET
+ && set_dest_equal_p (sub, mem))
+ return true;
+ }
+ }
+ return false;
+}
+
/* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE
array. */
@@ -2415,7 +2415,7 @@ noce_can_store_speculate_p (basic_block top_bb, const_rtx mem)
|| (CALL_P (insn) && (!RTL_CONST_CALL_P (insn)))))
return false;
- if (memory_modified_in_insn_p (mem, insn))
+ if (memory_must_be_modified_in_insn_p (mem, insn))
return true;
if (modified_in_p (XEXP (mem, 0), insn))
return false;
@@ -2616,6 +2616,7 @@ extern void init_alias_analysis (void);
extern void end_alias_analysis (void);
extern void vt_equate_reg_base_value (const_rtx, const_rtx);
extern bool memory_modified_in_insn_p (const_rtx, const_rtx);
+extern bool memory_must_be_modified_in_insn_p (const_rtx, const_rtx);
extern bool may_be_sp_based_p (rtx);
extern rtx gen_hard_reg_clobber (enum machine_mode, unsigned int);
extern rtx get_reg_known_value (unsigned int);