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re PR middle-end/168 (Spurious signed/unsigned comparison warning)

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PR middle-end/168
	* fold-const.c (tree_expr_nonnegative_p):  Handle addition
	and multiplication of zero extensions, floating point division,
	and integer<->fp, fp<->fp and zero extension conversions.
	The built-in ceil and floor functions preserve signedness.

	* gcc.dg/20030612-1.c: New test case.

From-SVN: r67850
This commit is contained in:
Roger Sayle 2003-06-12 20:33:02 +00:00 committed by Roger Sayle
parent 6356f89288
commit 96f26e4161
4 changed files with 111 additions and 7 deletions
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8
gcc/ChangeLog
View File

@ -1,3 +1,11 @@
2003-06-12 Roger Sayle <roger@eyesopen.com>
PR middle-end/168
* fold-const.c (tree_expr_nonnegative_p): Handle addition
and multiplication of zero extensions, floating point division,
and integer<->fp, fp<->fp and zero extension conversions.
The built-in ceil and floor functions preserve signedness.
2003-06-12 Kazu Hirata <kazu@cs.umass.edu>
* ChangeLog: Follow spelling conventions.

85
gcc/fold-const.c
View File

@ -8022,9 +8022,27 @@ tree_expr_nonnegative_p (t)
return ! REAL_VALUE_NEGATIVE (TREE_REAL_CST (t));
case PLUS_EXPR:
return FLOAT_TYPE_P (TREE_TYPE (t))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
if (FLOAT_TYPE_P (TREE_TYPE (t)))
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
/* zero_extend(x) + zero_extend(y) is non-negative is x and y are
both unsigned and at atleast 2 bits shorter than the result. */
if (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE
&& TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
&& TREE_CODE (TREE_OPERAND (t, 1)) == NOP_EXPR)
{
tree inner1 = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
tree inner2 = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0));
if (TREE_CODE (inner1) == INTEGER_TYPE && TREE_UNSIGNED (inner1)
&& TREE_CODE (inner2) == INTEGER_TYPE && TREE_UNSIGNED (inner2))
{
unsigned int prec = MAX (TYPE_PRECISION (inner1),
TYPE_PRECISION (inner2)) + 1;
return prec < TYPE_PRECISION (TREE_TYPE (t));
}
}
break;
case MULT_EXPR:
if (FLOAT_TYPE_P (TREE_TYPE (t)))
@ -8035,6 +8053,20 @@ tree_expr_nonnegative_p (t)
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
}
/* zero_extend(x) * zero_extend(y) is non-negative is x and y are
both unsigned and their total bits is shorter than the result. */
if (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE
&& TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
&& TREE_CODE (TREE_OPERAND (t, 1)) == NOP_EXPR)
{
tree inner1 = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
tree inner2 = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0));
if (TREE_CODE (inner1) == INTEGER_TYPE && TREE_UNSIGNED (inner1)
&& TREE_CODE (inner2) == INTEGER_TYPE && TREE_UNSIGNED (inner2))
return TYPE_PRECISION (inner1) + TYPE_PRECISION (inner2)
< TYPE_PRECISION (TREE_TYPE (t));
}
return 0;
case TRUNC_DIV_EXPR:
@ -8042,12 +8074,45 @@ tree_expr_nonnegative_p (t)
case FLOOR_DIV_EXPR:
case ROUND_DIV_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
case TRUNC_MOD_EXPR:
case CEIL_MOD_EXPR:
case FLOOR_MOD_EXPR:
case ROUND_MOD_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
case RDIV_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
case NOP_EXPR:
{
tree inner_type = TREE_TYPE (TREE_OPERAND (t, 0));
tree outer_type = TREE_TYPE (t);
if (TREE_CODE (outer_type) == REAL_TYPE)
{
if (TREE_CODE (inner_type) == REAL_TYPE)
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
if (TREE_CODE (inner_type) == INTEGER_TYPE)
{
if (TREE_UNSIGNED (inner_type))
return 1;
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
}
}
else if (TREE_CODE (outer_type) == INTEGER_TYPE)
{
if (TREE_CODE (inner_type) == REAL_TYPE)
return tree_expr_nonnegative_p (TREE_OPERAND (t,0));
if (TREE_CODE (inner_type) == INTEGER_TYPE)
return TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type)
&& TREE_UNSIGNED (inner_type);
}
}
break;
case COND_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 1))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 2));
@ -8097,6 +8162,12 @@ tree_expr_nonnegative_p (t)
case BUILT_IN_ATAN:
case BUILT_IN_ATANF:
case BUILT_IN_ATANL:
case BUILT_IN_CEIL:
case BUILT_IN_CEILF:
case BUILT_IN_CEILL:
case BUILT_IN_FLOOR:
case BUILT_IN_FLOORF:
case BUILT_IN_FLOORL:
return tree_expr_nonnegative_p (TREE_VALUE (arglist));
case BUILT_IN_POW:
@ -8115,10 +8186,10 @@ tree_expr_nonnegative_p (t)
if (truth_value_p (TREE_CODE (t)))
/* Truth values evaluate to 0 or 1, which is nonnegative. */
return 1;
else
/* We don't know sign of `t', so be conservative and return false. */
return 0;
}
/* We don't know sign of `t', so be conservative and return false. */
return 0;
}
/* Return true if `r' is known to be non-negative.

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2003-06-12 Roger Sayle <roger@eyesopen.com>
PR middle-end/168
* gcc.dg/20030612-1.c: New test case.
2003-06-12 Mark Mitchell <mark@codesourcery.com>
PR c++/10635

20
gcc/testsuite/gcc.dg/20030612-1.c Normal file
View File

@ -0,0 +1,20 @@
/* Derived from PR middle-end/168. */
/* { dg-do compile } */
/* { dg-options "-W" } */
extern void foo ();
unsigned char uc;
unsigned short int usi;
unsigned int ui;
void bar()
{
if (uc + usi >= ui) /* { dg-bogus "between signed and unsigned" } */
foo ();
if (uc * usi >= ui) /* { dg-bogus "between signed and unsigned" } */
foo ();
}