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re PR tree-optimization/56365 (Missed opportunities for smin/smax standard name patterns when compiling as C++)

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2016-03-14  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/56365
	* tree-ssa-phiopt.c (minmax_replacement): Handle alternate
	constants to compare against.

	* gcc.dg/tree-ssa/phi-opt-14.c: New testcase.

From-SVN: r234183
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Richard Biener 2016-03-14 14:50:40 +00:00 committed by Richard Biener
parent 4799603f1a
commit a9fee7cdc3
4 changed files with 135 additions and 15 deletions
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6
gcc/ChangeLog
View File

@ -1,3 +1,9 @@
2016-03-14 Richard Biener <rguenther@suse.de>
PR tree-optimization/56365
* tree-ssa-phiopt.c (minmax_replacement): Handle alternate
constants to compare against.
2016-03-14 Segher Boessenkool <segher@kernel.crashing.org>
PR target/70098

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2016-03-14 Richard Biener <rguenther@suse.de>
PR tree-optimization/56365
* gcc.dg/tree-ssa/phi-opt-14.c: New testcase.
2016-03-14 Segher Boessenkool <segher@kernel.crashing.org>
PR target/70098

37
gcc/testsuite/gcc.dg/tree-ssa/phi-opt-14.c Normal file
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@ -0,0 +1,37 @@
/* { dg-do compile } */
/* { dg-options "-O -fdump-tree-phiopt1" } */
int test_01 (int a)
{
if (127 <= a)
a = 127;
else if (a <= -128)
a = -128;
return a;
}
int test_02 (int a)
{
if (127 < a)
a = 127;
else if (a <= -128)
a = -128;
return a;
}
int test_03 (int a)
{
if (127 <= a)
a = 127;
else if (a < -128)
a = -128;
return a;
}
int test_04 (int a)
{
if (127 < a)
a = 127;
else if (a < -128)
a = -128;
return a;
}
/* { dg-final { scan-tree-dump-not "if" "phiopt1" } } */

102
gcc/tree-ssa-phiopt.c
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@ -1045,7 +1045,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
gassign *new_stmt;
edge true_edge, false_edge;
enum tree_code cmp, minmax, ass_code;
tree smaller, larger, arg_true, arg_false;
tree smaller, alt_smaller, larger, alt_larger, arg_true, arg_false;
gimple_stmt_iterator gsi, gsi_from;
type = TREE_TYPE (PHI_RESULT (phi));
@ -1059,15 +1059,59 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
/* This transformation is only valid for order comparisons. Record which
operand is smaller/larger if the result of the comparison is true. */
alt_smaller = NULL_TREE;
alt_larger = NULL_TREE;
if (cmp == LT_EXPR || cmp == LE_EXPR)
{
smaller = gimple_cond_lhs (cond);
larger = gimple_cond_rhs (cond);
/* If we have smaller < CST it is equivalent to smaller <= CST-1.
Likewise smaller <= CST is equivalent to smaller < CST+1. */
if (TREE_CODE (larger) == INTEGER_CST)
{
if (cmp == LT_EXPR)
{
bool overflow;
wide_int alt = wi::sub (larger, 1, TYPE_SIGN (TREE_TYPE (larger)),
&overflow);
if (! overflow)
alt_larger = wide_int_to_tree (TREE_TYPE (larger), alt);
}
else
{
bool overflow;
wide_int alt = wi::add (larger, 1, TYPE_SIGN (TREE_TYPE (larger)),
&overflow);
if (! overflow)
alt_larger = wide_int_to_tree (TREE_TYPE (larger), alt);
}
}
}
else if (cmp == GT_EXPR || cmp == GE_EXPR)
{
smaller = gimple_cond_rhs (cond);
larger = gimple_cond_lhs (cond);
/* If we have larger > CST it is equivalent to larger >= CST+1.
Likewise larger >= CST is equivalent to larger > CST-1. */
if (TREE_CODE (smaller) == INTEGER_CST)
{
if (cmp == GT_EXPR)
{
bool overflow;
wide_int alt = wi::add (smaller, 1, TYPE_SIGN (TREE_TYPE (smaller)),
&overflow);
if (! overflow)
alt_smaller = wide_int_to_tree (TREE_TYPE (smaller), alt);
}
else
{
bool overflow;
wide_int alt = wi::sub (smaller, 1, TYPE_SIGN (TREE_TYPE (smaller)),
&overflow);
if (! overflow)
alt_smaller = wide_int_to_tree (TREE_TYPE (smaller), alt);
}
}
}
else
return false;
@ -1098,8 +1142,12 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
if (empty_block_p (middle_bb))
{
if (operand_equal_for_phi_arg_p (arg_true, smaller)
&& operand_equal_for_phi_arg_p (arg_false, larger))
if ((operand_equal_for_phi_arg_p (arg_true, smaller)
|| (alt_smaller
&& operand_equal_for_phi_arg_p (arg_true, alt_smaller)))
&& (operand_equal_for_phi_arg_p (arg_false, larger)
|| (alt_larger
&& operand_equal_for_phi_arg_p (arg_true, alt_larger))))
{
/* Case
@ -1109,8 +1157,12 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
rslt = larger; */
minmax = MIN_EXPR;
}
else if (operand_equal_for_phi_arg_p (arg_false, smaller)
&& operand_equal_for_phi_arg_p (arg_true, larger))
else if ((operand_equal_for_phi_arg_p (arg_false, smaller)
|| (alt_smaller
&& operand_equal_for_phi_arg_p (arg_false, alt_smaller)))
&& (operand_equal_for_phi_arg_p (arg_true, larger)
|| (alt_larger
&& operand_equal_for_phi_arg_p (arg_true, alt_larger))))
minmax = MAX_EXPR;
else
return false;
@ -1148,7 +1200,9 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
if (!operand_equal_for_phi_arg_p (lhs, arg_true))
return false;
if (operand_equal_for_phi_arg_p (arg_false, larger))
if (operand_equal_for_phi_arg_p (arg_false, larger)
|| (alt_larger
&& operand_equal_for_phi_arg_p (arg_false, alt_larger)))
{
/* Case
@ -1161,9 +1215,13 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
return false;
minmax = MIN_EXPR;
if (operand_equal_for_phi_arg_p (op0, smaller))
if (operand_equal_for_phi_arg_p (op0, smaller)
|| (alt_smaller
&& operand_equal_for_phi_arg_p (op0, alt_smaller)))
bound = op1;
else if (operand_equal_for_phi_arg_p (op1, smaller))
else if (operand_equal_for_phi_arg_p (op1, smaller)
|| (alt_smaller
&& operand_equal_for_phi_arg_p (op1, alt_smaller)))
bound = op0;
else
return false;
@ -1173,7 +1231,9 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
bound, larger)))
return false;
}
else if (operand_equal_for_phi_arg_p (arg_false, smaller))
else if (operand_equal_for_phi_arg_p (arg_false, smaller)
|| (alt_smaller
&& operand_equal_for_phi_arg_p (arg_false, alt_smaller)))
{
/* Case
@ -1186,9 +1246,13 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
return false;
minmax = MAX_EXPR;
if (operand_equal_for_phi_arg_p (op0, larger))
if (operand_equal_for_phi_arg_p (op0, larger)
|| (alt_larger
&& operand_equal_for_phi_arg_p (op0, alt_larger)))
bound = op1;
else if (operand_equal_for_phi_arg_p (op1, larger))
else if (operand_equal_for_phi_arg_p (op1, larger)
|| (alt_larger
&& operand_equal_for_phi_arg_p (op1, alt_larger)))
bound = op0;
else
return false;
@ -1207,7 +1271,9 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
if (!operand_equal_for_phi_arg_p (lhs, arg_false))
return false;
if (operand_equal_for_phi_arg_p (arg_true, larger))
if (operand_equal_for_phi_arg_p (arg_true, larger)
|| (alt_larger
&& operand_equal_for_phi_arg_p (arg_true, alt_larger)))
{
/* Case
@ -1220,9 +1286,13 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
return false;
minmax = MAX_EXPR;
if (operand_equal_for_phi_arg_p (op0, smaller))
if (operand_equal_for_phi_arg_p (op0, smaller)
|| (alt_smaller
&& operand_equal_for_phi_arg_p (op0, alt_smaller)))
bound = op1;
else if (operand_equal_for_phi_arg_p (op1, smaller))
else if (operand_equal_for_phi_arg_p (op1, smaller)
|| (alt_smaller
&& operand_equal_for_phi_arg_p (op1, alt_smaller)))
bound = op0;
else
return false;
@ -1232,7 +1302,9 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
bound, larger)))
return false;
}
else if (operand_equal_for_phi_arg_p (arg_true, smaller))
else if (operand_equal_for_phi_arg_p (arg_true, smaller)
|| (alt_smaller
&& operand_equal_for_phi_arg_p (arg_true, alt_smaller)))
{
/* Case