* PATCH to gimplify_modify_expr to avoid extra copies
@ 2004-06-11 5:43 Jason Merrill
2004-06-11 6:08 ` Jason Merrill
0 siblings, 1 reply; 5+ messages in thread
From: Jason Merrill @ 2004-06-11 5:43 UTC (permalink / raw)
To: gcc-patches; +Cc: bbooth, Richard Kenner
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This patch should help to avoid the extra copies kenner has been seeing.
Brian, can you make sure that my comment about V_MAY_DEF is accurate when
you check in your patch? :)
Tested x86_64-pc-linux-gnu, applied to trunk.
2004-06-10 Jason Merrill <jason@redhat.com>
* gimplify.c (gimplify_modify_expr): Don't force a temporary
of an aggregate_value_p type.
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*** gimplify.c.~1~ 2004-06-10 16:27:29.000000000 -0400
--- gimplify.c 2004-06-10 22:54:18.000000000 -0400
*************** gimplify_modify_expr (tree *expr_p, tree
*** 2493,2504 ****
FIXME this should be handled by the is_gimple_rhs predicate. */
! if (TREE_CODE (*from_p) == CALL_EXPR
! || (flag_non_call_exceptions && tree_could_trap_p (*from_p))
! /* If we're dealing with a renamable type, either source or dest
! must be a renamed variable. */
! || (is_gimple_reg_type (TREE_TYPE (*from_p))
! && !is_gimple_reg (*to_p)))
gimplify_expr (from_p, pre_p, post_p, is_gimple_val, fb_rvalue);
/* If the value being copied is of variable width, expose the length
--- 2493,2508 ----
FIXME this should be handled by the is_gimple_rhs predicate. */
! if (aggregate_value_p (TREE_TYPE (*from_p), NULL_TREE))
! /* Don't force a temp of a large aggregate type; the copy could be
! arbitrarily expensive. Instead we will generate a V_MAY_DEF for
! the assignment. */;
! else if (TREE_CODE (*from_p) == CALL_EXPR
! || (flag_non_call_exceptions && tree_could_trap_p (*from_p))
! /* If we're dealing with a renamable type, either source or dest
! must be a renamed variable. */
! || (is_gimple_reg_type (TREE_TYPE (*from_p))
! && !is_gimple_reg (*to_p)))
gimplify_expr (from_p, pre_p, post_p, is_gimple_val, fb_rvalue);
/* If the value being copied is of variable width, expose the length
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: PATCH to gimplify_modify_expr to avoid extra copies
2004-06-11 5:43 PATCH to gimplify_modify_expr to avoid extra copies Jason Merrill
@ 2004-06-11 6:08 ` Jason Merrill
2004-06-11 6:36 ` Richard Henderson
2004-06-11 19:38 ` Jason Merrill
0 siblings, 2 replies; 5+ messages in thread
From: Jason Merrill @ 2004-06-11 6:08 UTC (permalink / raw)
To: gcc-patches; +Cc: bbooth, Richard Henderson
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On Thu, 10 Jun 2004 23:05:53 -0400, Jason Merrill <jason@redhat.com> wrote:
> Brian, can you make sure that my comment about V_MAY_DEF is accurate when
> you check in your patch? :)
>
> ! /* Don't force a temp of a large aggregate type; the copy could be
> ! arbitrarily expensive. Instead we will generate a V_MAY_DEF for
> ! the assignment. */;
Ah, I see you already checked it in. Does something like this make sense
to you?
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*** tree-ssa-operands.c.~1~ 2004-06-10 23:07:12.000000000 -0400
--- tree-ssa-operands.c 2004-06-10 23:24:32.000000000 -0400
*************** get_stmt_operands (tree stmt)
*** 821,827 ****
if (TREE_CODE (TREE_OPERAND (stmt, 0)) == ARRAY_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == COMPONENT_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == REALPART_EXPR
! || TREE_CODE (TREE_OPERAND (stmt, 0)) == IMAGPART_EXPR)
get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_is_def,
&prev_vops);
else
--- 821,833 ----
if (TREE_CODE (TREE_OPERAND (stmt, 0)) == ARRAY_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == COMPONENT_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == REALPART_EXPR
! || TREE_CODE (TREE_OPERAND (stmt, 0)) == IMAGPART_EXPR
! /* Use a V_MAY_DEF if the RHS might throw, as the LHS won't be
! modified in that case. FIXME we should represent somehow
! that it is killed on the fallthrough path. */
! || TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR
! || (flag_non_call_exceptions
! && tree_could_trap_p (TREE_OPERAND (stmt, 1))))
get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_is_def,
&prev_vops);
else
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: PATCH to gimplify_modify_expr to avoid extra copies
2004-06-11 6:08 ` Jason Merrill
@ 2004-06-11 6:36 ` Richard Henderson
2004-06-11 19:38 ` Jason Merrill
1 sibling, 0 replies; 5+ messages in thread
From: Richard Henderson @ 2004-06-11 6:36 UTC (permalink / raw)
To: Jason Merrill; +Cc: gcc-patches, bbooth
On Thu, Jun 10, 2004 at 11:27:25PM -0400, Jason Merrill wrote:
> ! /* Use a V_MAY_DEF if the RHS might throw, as the LHS won't be
> ! modified in that case. FIXME we should represent somehow
> ! that it is killed on the fallthrough path. */
> ! || TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR
> ! || (flag_non_call_exceptions
> ! && tree_could_trap_p (TREE_OPERAND (stmt, 1))))
After gimplification, we can do better than this; use tree_could_throw_p.
Hmm, I see we currently only use this on complete statements. There's a
bug here for expressions -- the final return should be checking
tree_could_trap_p.
r~
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: PATCH to gimplify_modify_expr to avoid extra copies
2004-06-11 6:08 ` Jason Merrill
2004-06-11 6:36 ` Richard Henderson
@ 2004-06-11 19:38 ` Jason Merrill
1 sibling, 0 replies; 5+ messages in thread
From: Jason Merrill @ 2004-06-11 19:38 UTC (permalink / raw)
To: gcc-patches; +Cc: bbooth, Richard Henderson
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I'm applying this patch. Tested x86_64-pc-linux-gnu.
2004-06-11 Jason Merrill <jason@redhat.com>
* tree-ssa-operands.c: Use a V_MAY_DEF if the assignment might
throw.
* tree-eh.c (tree_could_throw_p): Support non-call exceptions in
expressions.
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Index: gcc/tree-eh.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-eh.c,v
retrieving revision 2.3
diff -c -p -r2.3 tree-eh.c
*** gcc/tree-eh.c 30 May 2004 18:32:29 -0000 2.3
--- gcc/tree-eh.c 11 Jun 2004 17:33:12 -0000
*************** tree_could_throw_p (tree t)
*** 1716,1739 ****
return false;
if (TREE_CODE (t) == MODIFY_EXPR)
{
! tree sub = TREE_OPERAND (t, 1);
! if (TREE_CODE (sub) == CALL_EXPR)
! t = sub;
! else
! {
! if (flag_non_call_exceptions)
! {
! if (tree_could_trap_p (sub))
! return true;
! return tree_could_trap_p (TREE_OPERAND (t, 0));
! }
! return false;
! }
}
if (TREE_CODE (t) == CALL_EXPR)
return (call_expr_flags (t) & ECF_NOTHROW) == 0;
!
return false;
}
--- 1716,1731 ----
return false;
if (TREE_CODE (t) == MODIFY_EXPR)
{
! if (flag_non_call_exceptions
! && tree_could_trap_p (TREE_OPERAND (t, 0)))
! return true;
! t = TREE_OPERAND (t, 1);
}
if (TREE_CODE (t) == CALL_EXPR)
return (call_expr_flags (t) & ECF_NOTHROW) == 0;
! if (flag_non_call_exceptions)
! return tree_could_trap_p (t);
return false;
}
Index: gcc/tree-ssa-operands.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-ssa-operands.c,v
retrieving revision 2.5
diff -c -p -r2.5 tree-ssa-operands.c
*** gcc/tree-ssa-operands.c 10 Jun 2004 21:41:07 -0000 2.5
--- gcc/tree-ssa-operands.c 11 Jun 2004 17:33:12 -0000
*************** get_stmt_operands (tree stmt)
*** 821,827 ****
if (TREE_CODE (TREE_OPERAND (stmt, 0)) == ARRAY_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == COMPONENT_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == REALPART_EXPR
! || TREE_CODE (TREE_OPERAND (stmt, 0)) == IMAGPART_EXPR)
get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_is_def,
&prev_vops);
else
--- 821,831 ----
if (TREE_CODE (TREE_OPERAND (stmt, 0)) == ARRAY_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == COMPONENT_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == REALPART_EXPR
! || TREE_CODE (TREE_OPERAND (stmt, 0)) == IMAGPART_EXPR
! /* Use a V_MAY_DEF if the RHS might throw, as the LHS won't be
! modified in that case. FIXME we should represent somehow
! that it is killed on the fallthrough path. */
! || tree_could_throw_p (TREE_OPERAND (stmt, 1)))
get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_is_def,
&prev_vops);
else
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: PATCH to gimplify_modify_expr to avoid extra copies
@ 2004-06-11 17:55 Richard Kenner
0 siblings, 0 replies; 5+ messages in thread
From: Richard Kenner @ 2004-06-11 17:55 UTC (permalink / raw)
To: jason; +Cc: gcc-patches
This patch should help to avoid the extra copies kenner has been seeing.
I *think* it does, but can't be sure (I'm blowing up in a different place
in that file and can't be sure that it's later; I'm travelling now).
^ permalink raw reply [flat|nested] 5+ messages in thread
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2004-06-11 5:43 PATCH to gimplify_modify_expr to avoid extra copies Jason Merrill
2004-06-11 6:08 ` Jason Merrill
2004-06-11 6:36 ` Richard Henderson
2004-06-11 19:38 ` Jason Merrill
2004-06-11 17:55 Richard Kenner
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