+2010-08-09 Bingfeng Mei <bmei@broadcom.com>
+
+ * ddg.c (walk_mems_2): Moved from alias.c, use may_alias_p instead of
+ alias_sets_conflict_p.
+ (walk_mems_1): Moved from alias.c.
+ (insns_may_alias_p): New function, originally insn_alias_sets_conflict_p
+ in alias.c.
+ (add_inter_loop_mem_dep): Use insns_may_alias_p now.
+ * cse.c (cse_insn): New argument in calling nonoverlapping_memrefs_p.
+ * alias.c (walk_mems_2): Moved to ddg.c.
+ (walk_mems_1): Ditto.
+ (insn_alias_sets_conflict_p): Renamed to insns_may_alias_p and moved
+ to ddg.c.
+ (nonoverlapping_memrefs_p): Add flag to guard offset-based memory
+ disambiguation.
+ *(may_alias_p): New function to check whether two memory expression
+ may alias or not. Currently used in buidling inter-iteration memory
+ dependence.
+ *alias.h (nonoverlapping_memrefs_p): New flag as third argument.
+ (insn_alias_sets_conflict_p): Removed
+ *rtl.h (may_alias_p): New function prototype.
+
2010-08-09 Nathan Froyd <froydnj@codesourcery.com>
* tree.c (nreverse): Assert that we don't have a BLOCK.
return 0;
}
-static int
-walk_mems_2 (rtx *x, rtx mem)
-{
- if (MEM_P (*x))
- {
- if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem)))
- return 1;
-
- return -1;
- }
- return 0;
-}
-
-static int
-walk_mems_1 (rtx *x, rtx *pat)
-{
- if (MEM_P (*x))
- {
- /* Visit all MEMs in *PAT and check indepedence. */
- if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x))
- /* Indicate that dependence was determined and stop traversal. */
- return 1;
-
- return -1;
- }
- return 0;
-}
-
-/* Return 1 if two specified instructions have mem expr with conflict alias sets*/
-bool
-insn_alias_sets_conflict_p (rtx insn1, rtx insn2)
-{
- /* For each pair of MEMs in INSN1 and INSN2 check their independence. */
- return for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1,
- &PATTERN (insn2));
-}
-
/* Return 1 if the two specified alias sets will always conflict. */
int
}
/* Return nonzero if we can determine the exprs corresponding to memrefs
- X and Y and they do not overlap. */
+ X and Y and they do not overlap.
+ If LOOP_VARIANT is set, skip offset-based disambiguation */
int
-nonoverlapping_memrefs_p (const_rtx x, const_rtx y)
+nonoverlapping_memrefs_p (const_rtx x, const_rtx y, bool loop_invariant)
{
tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y);
rtx rtlx, rtly;
|| (CONSTANT_P (basey) && REG_P (basex)
&& REGNO_PTR_FRAME_P (REGNO (basex))));
+ /* Offset based disambiguation not appropriate for loop invariant */
+ if (loop_invariant)
+ return 0;
+
sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx))
: MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx))
: -1);
if (DIFFERENT_ALIAS_SETS_P (x, mem))
return 0;
- if (nonoverlapping_memrefs_p (mem, x))
+ if (nonoverlapping_memrefs_p (mem, x, false))
return 0;
if (aliases_everything_p (x))
SIZE_FOR_MODE (x), x_addr, 0)) != -1)
return ret;
- if (nonoverlapping_memrefs_p (x, mem))
+ if (nonoverlapping_memrefs_p (x, mem, false))
return 0;
fixed_scalar
}
\f
+
+/* Check whether X may be aliased with MEM. Don't do offset-based
+ memory disambiguation & TBAA. */
+int
+may_alias_p (const_rtx mem, const_rtx x)
+{
+ rtx x_addr, mem_addr;
+ int ret;
+
+ if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
+ return 1;
+
+ /* ??? In true_dependence we also allow BLKmode to alias anything. */
+ if (GET_MODE (mem) == BLKmode || GET_MODE (x) == BLKmode)
+ return 1;
+
+ if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
+ || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
+ return 1;
+
+ /* Read-only memory is by definition never modified, and therefore can't
+ conflict with anything. We don't expect to find read-only set on MEM,
+ but stupid user tricks can produce them, so don't die. */
+ if (MEM_READONLY_P (x))
+ return 0;
+
+ /* If we have MEMs refering to different address spaces (which can
+ potentially overlap), we cannot easily tell from the addresses
+ whether the references overlap. */
+ if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
+ return 1;
+
+ x_addr = XEXP (x, 0);
+ mem_addr = XEXP (mem, 0);
+ if (!((GET_CODE (x_addr) == VALUE
+ && GET_CODE (mem_addr) != VALUE
+ && reg_mentioned_p (x_addr, mem_addr))
+ || (GET_CODE (x_addr) != VALUE
+ && GET_CODE (mem_addr) == VALUE
+ && reg_mentioned_p (mem_addr, x_addr))))
+ {
+ x_addr = get_addr (x_addr);
+ mem_addr = get_addr (mem_addr);
+ }
+
+ if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), GET_MODE (mem_addr)))
+ return 0;
+
+ x_addr = canon_rtx (x_addr);
+ mem_addr = canon_rtx (mem_addr);
+
+ if (nonoverlapping_memrefs_p (mem, x, true))
+ return 0;
+
+ if (aliases_everything_p (x))
+ return 1;
+
+ /* We cannot use aliases_everything_p to test MEM, since we must look
+ at MEM_ADDR, rather than XEXP (mem, 0). */
+ if (GET_MODE (mem) == QImode || GET_CODE (mem_addr) == AND)
+ return 1;
+
+ if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
+ rtx_addr_varies_p))
+ return 0;
+
+ /* TBAA not valid for loop_invarint */
+ return rtx_refs_may_alias_p (x, mem, false);
+}
+
void
init_alias_target (void)
{
}
+static int
+walk_mems_2 (rtx *x, rtx mem)
+{
+ if (MEM_P (*x))
+ {
+ if (may_alias_p (*x, mem))
+ return 1;
+
+ return -1;
+ }
+ return 0;
+}
+
+static int
+walk_mems_1 (rtx *x, rtx *pat)
+{
+ if (MEM_P (*x))
+ {
+ /* Visit all MEMs in *PAT and check indepedence. */
+ if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x))
+ /* Indicate that dependence was determined and stop traversal. */
+ return 1;
+
+ return -1;
+ }
+ return 0;
+}
+
+/* Return 1 if two specified instructions have mem expr with conflict alias sets*/
+static int
+insns_may_alias_p (rtx insn1, rtx insn2)
+{
+ /* For each pair of MEMs in INSN1 and INSN2 check their independence. */
+ return for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1,
+ &PATTERN (insn2));
+}
+
/* Given two nodes, analyze their RTL insns and add inter-loop mem deps
to ddg G. */
static void
add_inter_loop_mem_dep (ddg_ptr g, ddg_node_ptr from, ddg_node_ptr to)
{
- if (!insn_alias_sets_conflict_p (from->insn, to->insn))
+ if (!insns_may_alias_p (from->insn, to->insn))
/* Do not create edge if memory references have disjoint alias sets. */
return;
projects / thirdparty / gcc.git / commitdiff
