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tree-vrp.c (simplify_bit_ops_using_ranges): New function.

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* tree-vrp.c (simplify_bit_ops_using_ranges): New function.
	(simplify_stmt_using_ranges): Use it.

	* gcc.dg/tree-ssa/vrp53.c: New test.

From-SVN: r162115
This commit is contained in:
Jakub Jelinek 2010-07-13 00:11:27 +02:00 committed by Jakub Jelinek
parent 8dc9f5bd88
commit 8556f58f76
4 changed files with 125 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2010-07-12 Jakub Jelinek <jakub@redhat.com>
* tree-vrp.c (simplify_bit_ops_using_ranges): New function.
(simplify_stmt_using_ranges): Use it.
2010-07-12 Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
* config/spu/spu.h (struct spu_builtin_description): Remove FNDECL

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2010-07-12 Jakub Jelinek <jakub@redhat.com>
* gcc.dg/tree-ssa/vrp53.c: New test.
2010-07-12 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/44907

24
gcc/testsuite/gcc.dg/tree-ssa/vrp53.c Normal file
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@ -0,0 +1,24 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-vrp1" } */
int
f1 (int x)
{
x &= 0xff;
x += 0x400;
x &= 0x7ff;
return x;
}
int
f2 (int x)
{
x &= 0xff;
x += 0x5400;
x |= 0x4400;
return x;
}
/* { dg-final { scan-tree-dump-not "\& (2047|0x7ff)" "vrp1" } } */
/* { dg-final { scan-tree-dump-not "\\| (17408|0x4400)" "vrp1" } } */
/* { dg-final { cleanup-tree-dump "vrp1" } } */

92
gcc/tree-vrp.c
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@ -6913,6 +6913,89 @@ simplify_abs_using_ranges (gimple stmt)
return false;
}
/* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
If all the bits that are being cleared by & are already
known to be zero from VR, or all the bits that are being
set by | are already known to be one from VR, the bit
operation is redundant. */
static bool
simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
{
tree op0 = gimple_assign_rhs1 (stmt);
tree op1 = gimple_assign_rhs2 (stmt);
tree op = NULL_TREE;
value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
double_int may_be_nonzero0, may_be_nonzero1;
double_int must_be_nonzero0, must_be_nonzero1;
double_int mask;
if (TREE_CODE (op0) == SSA_NAME)
vr0 = *(get_value_range (op0));
else if (is_gimple_min_invariant (op0))
set_value_range_to_value (&vr0, op0, NULL);
else
return false;
if (TREE_CODE (op1) == SSA_NAME)
vr1 = *(get_value_range (op1));
else if (is_gimple_min_invariant (op1))
set_value_range_to_value (&vr1, op1, NULL);
else
return false;
if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
return false;
if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
return false;
switch (gimple_assign_rhs_code (stmt))
{
case BIT_AND_EXPR:
mask = double_int_and (may_be_nonzero0,
double_int_not (must_be_nonzero1));
if (double_int_zero_p (mask))
{
op = op0;
break;
}
mask = double_int_and (may_be_nonzero1,
double_int_not (must_be_nonzero0));
if (double_int_zero_p (mask))
{
op = op1;
break;
}
break;
case BIT_IOR_EXPR:
mask = double_int_and (may_be_nonzero0,
double_int_not (must_be_nonzero1));
if (double_int_zero_p (mask))
{
op = op1;
break;
}
mask = double_int_and (may_be_nonzero1,
double_int_not (must_be_nonzero0));
if (double_int_zero_p (mask))
{
op = op0;
break;
}
break;
default:
gcc_unreachable ();
}
if (op == NULL_TREE)
return false;
gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
update_stmt (gsi_stmt (*gsi));
return true;
}
/* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
a known value range VR.
@ -7198,6 +7281,15 @@ simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
return simplify_abs_using_ranges (stmt);
break;
case BIT_AND_EXPR:
case BIT_IOR_EXPR:
/* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
if all the bits being cleared are already cleared or
all the bits being set are already set. */
if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
return simplify_bit_ops_using_ranges (gsi, stmt);
break;
default:
break;
}