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fold-const.c (fold): Convert (T)(x&c) into ((T)x&(T)c) for integer constant c (if...

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* fold-const.c (fold) [NOP_EXPR]: Convert (T)(x&c) into ((T)x&(T)c)
	for integer constant c (if x has unsigned type or sign bit is not
	set in c).  This folds the zero/sign extension into the bit-wise and
	operation.

	* gcc.c-torture/compile/20020415-1.c: New.

Co-Authored-By: Jakub Jelinek <jakub@redhat.com>

From-SVN: r52465
This commit is contained in:
Roger Sayle 2002-04-18 10:39:41 +00:00 committed by Jakub Jelinek
parent 692efa8ed5
commit 58c2956cc7
4 changed files with 77 additions and 0 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2002-04-18 Roger Sayle <roger@eyesopen.com>
Jakub Jelinek <jakub@redhat.com>
* fold-const.c (fold) [NOP_EXPR]: Convert (T)(x&c) into ((T)x&(T)c)
for integer constant c (if x has unsigned type or sign bit is not
set in c). This folds the zero/sign extension into the bit-wise and
operation.
2002-04-18 Jakub Jelinek <jakub@redhat.com>
PR middle-end/6205

43
gcc/fold-const.c
View File

@ -4695,6 +4695,49 @@ fold (expr)
TREE_USED (t) = 1;
return t;
}
/* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
constants (if x has signed type, the sign bit cannot be set
in c). This folds extension into the BIT_AND_EXPR. */
if (INTEGRAL_TYPE_P (TREE_TYPE (t))
&& TREE_CODE (TREE_OPERAND (t, 0)) == BIT_AND_EXPR
&& TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 1)) == INTEGER_CST)
{
tree and = TREE_OPERAND (t, 0);
tree and0 = TREE_OPERAND (and, 0), and1 = TREE_OPERAND (and, 1);
int change = 0;
if (TREE_UNSIGNED (TREE_TYPE (and))
|| (TYPE_PRECISION (TREE_TYPE (t))
<= TYPE_PRECISION (TREE_TYPE (and))))
change = 1;
else if (TYPE_PRECISION (TREE_TYPE (and1))
<= HOST_BITS_PER_WIDE_INT
&& host_integerp (and1, 1))
{
unsigned HOST_WIDE_INT cst;
cst = tree_low_cst (and1, 1);
cst &= (HOST_WIDE_INT) -1
<< (TYPE_PRECISION (TREE_TYPE (and1)) - 1);
change = (cst == 0);
#ifdef LOAD_EXTEND_OP
if (change
&& (LOAD_EXTEND_OP (TYPE_MODE (TREE_TYPE (and0)))
== ZERO_EXTEND))
{
tree uns = unsigned_type (TREE_TYPE (and0));
and0 = convert (uns, and0);
and1 = convert (uns, and1);
}
#endif
}
if (change)
return fold (build (BIT_AND_EXPR, TREE_TYPE (t),
convert (TREE_TYPE (t), and0),
convert (TREE_TYPE (t), and1)));
}
if (!wins)
{
TREE_CONSTANT (t) = TREE_CONSTANT (arg0);

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2002-04-18 Roger Sayle <roger@eyesopen.com>
* gcc.c-torture/compile/20020415-1.c: New.
2002-04-18 David S. Miller <davem@redhat.com>
* gcc.c-torture/execute/20020418-1.c: New test.

22
gcc/testsuite/gcc.c-torture/compile/20020415-1.c Normal file
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@ -0,0 +1,22 @@
/* Check that floating point casts of integer operations don't ICE. */
/* The first of these routines caused problems for a patch, that wasn't
otherwise caught by a full bootstrap, the regression test suite or
SPEC CPU2000. */
double
andop (unsigned int x)
{
return x & 1;
}
double
orop (unsigned int x)
{
return x | 1;
}
double
notop (unsigned int x)
{
return ~x;
}