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fold-const.c (build_range_check): Optimize (c>=1) && (c<=127) into the equivalent (signed char)c > 0.

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* fold-const.c (build_range_check): Optimize (c>=1) && (c<=127)
	into the equivalent (signed char)c > 0.

	* gcc.c-torture/execute/20020510-1.c: New test case.

From-SVN: r53373
This commit is contained in:
Roger Sayle 2002-05-10 22:24:13 +00:00 • committed by Roger Sayle
parent 79a497cd1d
commit dbfb1116b3
4 changed files with 142 additions and 16 deletions
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5
gcc/ChangeLog
View file

@ -1,3 +1,8 @@
2002-05-10 Roger Sayle <roger@eyesopen.com>
* fold-const.c (build_range_check): Optimize (c>=1) && (c<=127)
into the equivalent (signed char)c > 0.
2002-05-10 Janis Johnson <janis187@us.ibm.com>
* loop.c: (PREFETCH_EXTREME_DIFFERENCE, PREFETCH_BEFORE_LOOP): New.

64
gcc/fold-const.c
View file

@ -3091,41 +3091,73 @@ build_range_check (type, exp, in_p, low, high)
tree low, high;
{
tree etype = TREE_TYPE (exp);
tree utype, value;
tree value;
if (! in_p
&& (0 != (value = build_range_check (type, exp, 1, low, high))))
return invert_truthvalue (value);
else if (low == 0 && high == 0)
if (low == 0 && high == 0)
return convert (type, integer_one_node);
else if (low == 0)
if (low == 0)
return fold (build (LE_EXPR, type, exp, high));
else if (high == 0)
if (high == 0)
return fold (build (GE_EXPR, type, exp, low));
else if (operand_equal_p (low, high, 0))
if (operand_equal_p (low, high, 0))
return fold (build (EQ_EXPR, type, exp, low));
else if (TREE_UNSIGNED (etype) && integer_zerop (low))
return build_range_check (type, exp, 1, 0, high);
else if (integer_zerop (low))
if (integer_zerop (low))
{
utype = (*lang_hooks.types.unsigned_type) (etype);
return build_range_check (type, convert (utype, exp), 1, 0,
convert (utype, high));
if (! TREE_UNSIGNED (etype))
{
etype = (*lang_hooks.types.unsigned_type) (etype);
high = convert (etype, high);
exp = convert (etype, exp);
}
return build_range_check (type, exp, 1, 0, high);
}
else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
&& ! TREE_OVERFLOW (value))
/* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
if (integer_onep (low) && TREE_CODE (high) == INTEGER_CST)
{
unsigned HOST_WIDE_INT lo;
HOST_WIDE_INT hi;
int prec;
prec = TYPE_PRECISION (etype);
if (prec <= HOST_BITS_PER_WIDE_INT)
{
hi = 0;
lo = ((unsigned HOST_WIDE_INT) 1 << (prec - 1)) - 1;
}
else
{
hi = ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)) - 1;
lo = (unsigned HOST_WIDE_INT) -1;
}
if (TREE_INT_CST_HIGH (high) == hi && TREE_INT_CST_LOW (high) == lo)
{
if (TREE_UNSIGNED (etype))
{
etype = (*lang_hooks.types.signed_type) (etype);
exp = convert (etype, exp);
}
return fold (build (GT_EXPR, type, exp,
convert (etype, integer_zero_node)));
}
}
if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
&& ! TREE_OVERFLOW (value))
return build_range_check (type,
fold (build (MINUS_EXPR, etype, exp, low)),
1, convert (etype, integer_zero_node), value);
else
return 0;
return 0;
}
/* Given two ranges, see if we can merge them into one. Return 1 if we

4
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,7 @@
2002-05-10 Roger Sayle <roger@eyesopen.com>
* gcc.c-torture/execute/20020510-1.c: New test case.
2002-05-10 David S. Miller <davem@redhat.com>
* gcc.c-torture/execute/conversion.c: Test long double too.

85
gcc/testsuite/gcc.c-torture/execute/20020510-1.c Normal file
View file

@ -0,0 +1,85 @@
/* Copyright (C) 2002 Free Software Foundation.
Test that optimizing ((c>=1) && (c<=127)) into (signed char)c < 0
doesn't cause any problems for the compiler and behaves correctly.
Written by Roger Sayle, 8th May 2002. */
#include <limits.h>
extern void abort (void);
void
testc (unsigned char c, int ok)
{
if ((c>=1) && (c<=SCHAR_MAX))
{
if (!ok) abort ();
}
else
if (ok) abort ();
}
void
tests (unsigned short s, int ok)
{
if ((s>=1) && (s<=SHRT_MAX))
{
if (!ok) abort ();
}
else
if (ok) abort ();
}
void
testi (unsigned int i, int ok)
{
if ((i>=1) && (i<=INT_MAX))
{
if (!ok) abort ();
}
else
if (ok) abort ();
}
void
testl (unsigned long l, int ok)
{
if ((l>=1) && (l<=LONG_MAX))
{
if (!ok) abort ();
}
else
if (ok) abort ();
}
int
main ()
{
testc (0, 0);
testc (1, 1);
testc (SCHAR_MAX, 1);
testc (SCHAR_MAX+1, 0);
testc (UCHAR_MAX, 0);
tests (0, 0);
tests (1, 1);
tests (SHRT_MAX, 1);
tests (SHRT_MAX+1, 0);
tests (USHRT_MAX, 0);
testi (0, 0);
testi (1, 1);
testi (INT_MAX, 1);
testi (INT_MAX+1U, 0);
testi (UINT_MAX, 0);
testl (0, 0);
testl (1, 1);
testl (LONG_MAX, 1);
testl (LONG_MAX+1UL, 0);
testl (ULONG_MAX, 0);
return 0;
}