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re PR tree-optimization/64705 (Bad code generation of sieve on x86-64 because of too aggressive IV optimizations) 

PR tree-optimization/64705
	* tree-ssa-loop-niter.h (expand_simple_operations): New parameter.
	* tree-ssa-loop-niter.c (expand_simple_operations): New parameter.
	* tree-ssa-loop-ivopts.c (extract_single_var_from_expr): New.
	(find_bivs, find_givs_in_stmt_scev): Pass new argument to
	expand_simple_operations.

	testsuite
	PR tree-optimization/64705
	* gcc.dg/tree-ssa/pr64705.c: New test.

From-SVN: r220676
This commit is contained in:
Bin Cheng 2015-02-13 05:44:46 +00:00
parent 785f21af82
commit fc06280eb1
6 changed files with 98 additions and 16 deletions
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13
gcc/ChangeLog
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@ -1,4 +1,13 @@
2015-02-12 H.J. Lu <hongjiu.lu@intel.com>
2015-02-13 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/64705
* tree-ssa-loop-niter.h (expand_simple_operations): New parameter.
* tree-ssa-loop-niter.c (expand_simple_operations): New parameter.
* tree-ssa-loop-ivopts.c (extract_single_var_from_expr): New.
(find_bivs, find_givs_in_stmt_scev): Pass new argument to
expand_simple_operations.
2015-02-13 H.J. Lu <hongjiu.lu@intel.com>
Richard Henderson <rth@redhat.com>
PR rtl/32219
@ -21,7 +30,7 @@
* config/rs6000/rs6000.c (rs6000_emit_epilogue): Fix typo in
code setting up r11 for out-of-line fp restore.
2015-02-12 Eric Botcazou <ebotcazou@adacore.com>
2015-02-13 Eric Botcazou <ebotcazou@adacore.com>
* config/visium/visium.opt (msv-mode): Add RejectNegative and Report.
(muser-mode): Likewise.

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2015-02-13 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/64705
* gcc.dg/tree-ssa/pr64705.c: New test.
2015-02-12 H.J. Lu <hongjiu.lu@intel.com>
PR rtl/32219

27
gcc/testsuite/gcc.dg/tree-ssa/pr64705.c Normal file
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@ -0,0 +1,27 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-ivopts-details" } */
double g;
int foo(char *flags, long len, long i, long steps)
{
register long step, iter;
if(*(flags + i))
{
step = i + i + 3;
for(iter = i + step ; iter <= len ; iter += step)
{
steps++;
*(flags + iter)=0;
}
}
g = 5.0*(double)steps;
return 0;
}
/* Don't expand iv {base+step, step}_loop into {base+x+y, step}_loop
even if "step == x + y". */
/* { dg-final { scan-tree-dump "base step_\[0-9\]* \\+ iter|base iter_\[0-9\]* \\+ step" "ivopts"} } */
/* { dg-final { cleanup-tree-dump "ivopts" } } */

49
gcc/tree-ssa-loop-ivopts.c
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@ -1081,13 +1081,40 @@ determine_biv_step (gphi *phi)
return integer_zerop (iv.step) ? NULL_TREE : iv.step;
}
/* Return the first non-invariant ssa var found in EXPR. */
static tree
extract_single_var_from_expr (tree expr)
{
int i, n;
tree tmp;
enum tree_code code;
if (!expr || is_gimple_min_invariant (expr))
return NULL;
code = TREE_CODE (expr);
if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
{
n = TREE_OPERAND_LENGTH (expr);
for (i = 0; i < n; i++)
{
tmp = extract_single_var_from_expr (TREE_OPERAND (expr, i));
if (tmp)
return tmp;
}
}
return (TREE_CODE (expr) == SSA_NAME) ? expr : NULL;
}
/* Finds basic ivs. */
static bool
find_bivs (struct ivopts_data *data)
{
gphi *phi;
tree step, type, base;
tree step, type, base, stop;
bool found = false;
struct loop *loop = data->current_loop;
gphi_iterator psi;
@ -1104,7 +1131,13 @@ find_bivs (struct ivopts_data *data)
continue;
base = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop));
base = expand_simple_operations (base);
/* Stop expanding iv base at the first ssa var referred by iv step.
Ideally we should stop at any ssa var, because that's expensive
and unusual to happen, we just do it on the first one.
See PR64705 for the rationale. */
stop = extract_single_var_from_expr (step);
base = expand_simple_operations (base, stop);
if (contains_abnormal_ssa_name_p (base)
|| contains_abnormal_ssa_name_p (step))
continue;
@ -1176,7 +1209,7 @@ mark_bivs (struct ivopts_data *data)
static bool
find_givs_in_stmt_scev (struct ivopts_data *data, gimple stmt, affine_iv *iv)
{
tree lhs;
tree lhs, stop;
struct loop *loop = data->current_loop;
iv->base = NULL_TREE;
@ -1191,13 +1224,19 @@ find_givs_in_stmt_scev (struct ivopts_data *data, gimple stmt, affine_iv *iv)
if (!simple_iv (loop, loop_containing_stmt (stmt), lhs, iv, true))
return false;
iv->base = expand_simple_operations (iv->base);
/* Stop expanding iv base at the first ssa var referred by iv step.
Ideally we should stop at any ssa var, because that's expensive
and unusual to happen, we just do it on the first one.
See PR64705 for the rationale. */
stop = extract_single_var_from_expr (iv->step);
iv->base = expand_simple_operations (iv->base, stop);
if (contains_abnormal_ssa_name_p (iv->base)
|| contains_abnormal_ssa_name_p (iv->step))
return false;
/* If STMT could throw, then do not consider STMT as defining a GIV.
/* If STMT could throw, then do not consider STMT as defining a GIV.
While this will suppress optimizations, we can not safely delete this
GIV and associated statements, even if it appears it is not used. */
if (stmt_could_throw_p (stmt))

18
gcc/tree-ssa-loop-niter.c
View File

@ -1563,10 +1563,11 @@ simplify_replace_tree (tree expr, tree old, tree new_tree)
}
/* Expand definitions of ssa names in EXPR as long as they are simple
enough, and return the new expression. */
enough, and return the new expression. If STOP is specified, stop
expanding if EXPR equals to it. */
tree
expand_simple_operations (tree expr)
expand_simple_operations (tree expr, tree stop)
{
unsigned i, n;
tree ret = NULL_TREE, e, ee, e1;
@ -1586,7 +1587,7 @@ expand_simple_operations (tree expr)
for (i = 0; i < n; i++)
{
e = TREE_OPERAND (expr, i);
ee = expand_simple_operations (e);
ee = expand_simple_operations (e, stop);
if (e == ee)
continue;
@ -1605,7 +1606,8 @@ expand_simple_operations (tree expr)
return ret;
}
if (TREE_CODE (expr) != SSA_NAME)
/* Stop if it's not ssa name or the one we don't want to expand. */
if (TREE_CODE (expr) != SSA_NAME || expr == stop)
return expr;
stmt = SSA_NAME_DEF_STMT (expr);
@ -1625,7 +1627,7 @@ expand_simple_operations (tree expr)
&& src->loop_father != dest->loop_father)
return expr;
return expand_simple_operations (e);
return expand_simple_operations (e, stop);
}
if (gimple_code (stmt) != GIMPLE_ASSIGN)
return expr;
@ -1645,7 +1647,7 @@ expand_simple_operations (tree expr)
return e;
if (code == SSA_NAME)
return expand_simple_operations (e);
return expand_simple_operations (e, stop);
return expr;
}
@ -1654,7 +1656,7 @@ expand_simple_operations (tree expr)
{
CASE_CONVERT:
/* Casts are simple. */
ee = expand_simple_operations (e);
ee = expand_simple_operations (e, stop);
return fold_build1 (code, TREE_TYPE (expr), ee);
case PLUS_EXPR:
@ -1669,7 +1671,7 @@ expand_simple_operations (tree expr)
if (!is_gimple_min_invariant (e1))
return expr;
ee = expand_simple_operations (e);
ee = expand_simple_operations (e, stop);
return fold_build2 (code, TREE_TYPE (expr), ee, e1);
default:

2
gcc/tree-ssa-loop-niter.h
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@ -20,7 +20,7 @@ along with GCC; see the file COPYING3. If not see
#ifndef GCC_TREE_SSA_LOOP_NITER_H
#define GCC_TREE_SSA_LOOP_NITER_H
extern tree expand_simple_operations (tree);
extern tree expand_simple_operations (tree, tree = NULL);
extern bool loop_only_exit_p (const struct loop *, const_edge);
extern bool number_of_iterations_exit (struct loop *, edge,
struct tree_niter_desc *niter, bool,