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fold-const.c (fold): Handle more simplifications allowed by IEEE.

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* fold-const.c (fold): Handle more simplifications allowed by IEEE.

Co-Authored-By: Sylvian Pion <Sylvain.Pion@sophia.inria.fr>

From-SVN: r29994
This commit is contained in:
Jeffrey A Law 1999-10-15 01:40:28 +00:00 committed by Jeff Law
parent db7eb3e895
commit 104140890a
2 changed files with 57 additions and 3 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
Thu Oct 14 19:38:42 1999 Jeffrey A Law (law@cygnus.com)
Sylvian Pion <Sylvain.Pion@sophia.inria.fr>
* fold-const.c (fold): Handle more simplifications allowed by IEEE.
Thu Oct 14 17:30:14 1999 Richard Henderson <rth@cygnus.com>
* sparc.md (*): Use {nonimmediate,register}_operand as appropriate

55
gcc/fold-const.c
View File

@ -4749,6 +4749,9 @@ fold (expr)
/* A + (-B) -> A - B */
if (TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
/* (-A) + B -> B - A */
if (TREE_CODE (arg0) == NEGATE_EXPR)
return fold (build (MINUS_EXPR, type, arg1, TREE_OPERAND (arg0, 0)));
else if (! FLOAT_TYPE_P (type))
{
if (integer_zerop (arg1))
@ -4867,6 +4870,11 @@ fold (expr)
|| flag_fast_math)
&& real_zerop (arg1))
return non_lvalue (convert (type, arg0));
/* x+(-0) equals x, even for IEEE. */
else if (REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (arg1)))
return non_lvalue (convert (type, arg0));
associate:
/* In most languages, can't associate operations on floats
through parentheses. Rather than remember where the parentheses
@ -4989,6 +4997,17 @@ fold (expr)
return t;
case MINUS_EXPR:
/* A - (-B) -> A + B */
if (TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
/* (-A) - CST -> (-CST) - A for floating point (what about ints ?) */
if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == REAL_CST)
return
fold (build (MINUS_EXPR, type,
build_real (TREE_TYPE (arg1),
REAL_VALUE_NEGATE (TREE_REAL_CST (arg1))),
TREE_OPERAND (arg0, 0)));
if (! FLOAT_TYPE_P (type))
{
if (! wins && integer_zerop (arg0))
@ -5009,9 +5028,6 @@ fold (expr)
TREE_OPERAND (arg1, 0))),
TREE_OPERAND (arg0, 1)));
}
/* Convert A - (-B) to A + B. */
else if (TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|| flag_fast_math)
@ -5037,6 +5053,11 @@ fold (expr)
goto associate;
case MULT_EXPR:
/* (-A) * (-B) -> A * B */
if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (MULT_EXPR, type, TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0)));
if (! FLOAT_TYPE_P (type))
{
if (integer_zerop (arg1))
@ -5230,6 +5251,11 @@ fold (expr)
#endif
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
/* (-A) / (-B) -> A / B */
if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (RDIV_EXPR, type, TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0)));
/* In IEEE floating point, x/1 is not equivalent to x for snans.
However, ANSI says we can drop signals, so we can do this anyway. */
if (real_onep (arg1))
@ -5662,6 +5688,29 @@ fold (expr)
case GT_EXPR:
case LE_EXPR:
case GE_EXPR:
if (FLOAT_TYPE_P (TREE_TYPE (arg0)))
{
/* (-a) CMP (-b) -> b CMP a */
if (TREE_CODE (arg0) == NEGATE_EXPR
&& TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (code, type, TREE_OPERAND (arg1, 0),
TREE_OPERAND (arg0, 0)));
/* (-a) CMP CST -> a swap(CMP) (-CST) */
if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == REAL_CST)
return
fold (build
(swap_tree_comparison (code), type,
TREE_OPERAND (arg0, 0),
build_real (TREE_TYPE (arg1),
REAL_VALUE_NEGATE (TREE_REAL_CST (arg1)))));
/* IEEE doesn't distinguish +0 and -0 in comparisons. */
/* a CMP (-0) -> a CMP 0 */
if (REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (arg1)))
return fold (build (code, type, arg0,
build_real (TREE_TYPE (arg1), dconst0)));
}
/* If one arg is a constant integer, put it last. */
if (TREE_CODE (arg0) == INTEGER_CST
&& TREE_CODE (arg1) != INTEGER_CST)