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ddg.c (walk_mems_2): Moved from alias.c, use may_alias_p instead of alias_sets_conflict_p.

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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.

From-SVN: r163037
This commit is contained in:
Bingfeng Mei 2010-08-09 14:44:03 +00:00 committed by Bingfeng Mei
parent 72ac05b04e
commit c6ea834c83
6 changed files with 142 additions and 45 deletions
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22
gcc/ChangeLog
View File

@ -1,3 +1,25 @@
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.

120
gcc/alias.c
View File

@ -452,43 +452,6 @@ alias_sets_conflict_p (alias_set_type set1, alias_set_type set2)
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
@ -2187,10 +2150,11 @@ adjust_offset_for_component_ref (tree x, rtx offset)
}
/* 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;
@ -2287,6 +2251,10 @@ nonoverlapping_memrefs_p (const_rtx x, const_rtx y)
|| (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);
@ -2413,7 +2381,7 @@ true_dependence_1 (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr,
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))
@ -2528,7 +2496,7 @@ write_dependence_p (const_rtx mem, const_rtx x, int writep)
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
@ -2559,6 +2527,76 @@ output_dependence (const_rtx mem, const_rtx x)
}
/* 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)
{

3
gcc/alias.h
View File

@ -42,8 +42,7 @@ extern void record_component_aliases (tree);
extern int alias_sets_conflict_p (alias_set_type, alias_set_type);
extern int alias_sets_must_conflict_p (alias_set_type, alias_set_type);
extern int objects_must_conflict_p (tree, tree);
extern int nonoverlapping_memrefs_p (const_rtx, const_rtx);
extern bool insn_alias_sets_conflict_p (rtx, rtx);
extern int nonoverlapping_memrefs_p (const_rtx, const_rtx, bool);
/* This alias set can be used to force a memory to conflict with all
other memories, creating a barrier across which no memory reference

2
gcc/cse.c
View File

@ -5015,7 +5015,7 @@ cse_insn (rtx insn)
dest = canon_rtx (SET_DEST (sets[i].rtl));
if (!MEM_P (src) || !MEM_P (dest)
|| !nonoverlapping_memrefs_p (src, dest))
|| !nonoverlapping_memrefs_p (src, dest, false))
break;
}

39
gcc/ddg.c
View File

@ -348,12 +348,49 @@ build_inter_loop_deps (ddg_ptr g)
}
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;

1
gcc/rtl.h
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@ -2424,6 +2424,7 @@ extern int canon_true_dependence (const_rtx, enum machine_mode, rtx, const_rtx,
extern int read_dependence (const_rtx, const_rtx);
extern int anti_dependence (const_rtx, const_rtx);
extern int output_dependence (const_rtx, const_rtx);
extern int may_alias_p (const_rtx, const_rtx);
extern void init_alias_target (void);
extern void init_alias_analysis (void);
extern void end_alias_analysis (void);