}
}
- /* Some addresses are known to be nonzero. We don't know
- their sign, but equality comparisons are known. */
- if (const_arg1 == const0_rtx
- && nonzero_address_p (folded_arg0))
- {
- if (code == EQ)
- return false_rtx;
- else if (code == NE)
- return true_rtx;
- }
-
/* See if the two operands are the same. */
- if (folded_arg0 == folded_arg1
- || (REG_P (folded_arg0)
- && REG_P (folded_arg1)
- && (REG_QTY (REGNO (folded_arg0))
- == REG_QTY (REGNO (folded_arg1))))
+ if ((REG_P (folded_arg0)
+ && REG_P (folded_arg1)
+ && (REG_QTY (REGNO (folded_arg0))
+ == REG_QTY (REGNO (folded_arg1))))
|| ((p0 = lookup (folded_arg0,
SAFE_HASH (folded_arg0, mode_arg0),
mode_arg0))
SAFE_HASH (folded_arg1, mode_arg0),
mode_arg0))
&& p0->first_same_value == p1->first_same_value))
- {
- /* Sadly two equal NaNs are not equivalent. */
- if (!HONOR_NANS (mode_arg0))
- return ((code == EQ || code == LE || code == GE
- || code == LEU || code == GEU || code == UNEQ
- || code == UNLE || code == UNGE
- || code == ORDERED)
- ? true_rtx : false_rtx);
- /* Take care for the FP compares we can resolve. */
- if (code == UNEQ || code == UNLE || code == UNGE)
- return true_rtx;
- if (code == LTGT || code == LT || code == GT)
- return false_rtx;
- }
+ folded_arg1 = folded_arg0;
/* If FOLDED_ARG0 is a register, see if the comparison we are
doing now is either the same as we did before or the reverse
/* If we are comparing against zero, see if the first operand is
equivalent to an IOR with a constant. If so, we may be able to
determine the result of this comparison. */
-
- if (const_arg1 == const0_rtx)
+ if (const_arg1 == const0_rtx && !const_arg0)
{
rtx y = lookup_as_function (folded_arg0, IOR);
rtx inner_const;
&& (inner_const = equiv_constant (XEXP (y, 1))) != 0
&& GET_CODE (inner_const) == CONST_INT
&& INTVAL (inner_const) != 0)
- {
- int sign_bitnum = GET_MODE_BITSIZE (mode_arg0) - 1;
- int has_sign = (HOST_BITS_PER_WIDE_INT >= sign_bitnum
- && (INTVAL (inner_const)
- & ((HOST_WIDE_INT) 1 << sign_bitnum)));
- rtx true_rtx = const_true_rtx, false_rtx = const0_rtx;
-
-#ifdef FLOAT_STORE_FLAG_VALUE
- if (SCALAR_FLOAT_MODE_P (mode))
- {
- true_rtx = (CONST_DOUBLE_FROM_REAL_VALUE
- (FLOAT_STORE_FLAG_VALUE (mode), mode));
- false_rtx = CONST0_RTX (mode);
- }
-#endif
-
- switch (code)
- {
- case EQ:
- return false_rtx;
- case NE:
- return true_rtx;
- case LT: case LE:
- if (has_sign)
- return true_rtx;
- break;
- case GT: case GE:
- if (has_sign)
- return false_rtx;
- break;
- default:
- break;
- }
- }
+ folded_arg0 = gen_rtx_IOR (mode_arg0, XEXP (y, 0), inner_const);
}
{
return NULL_RTX;
}
+enum
+{
+ CR_EQ = 1,
+ CR_LT = 2,
+ CR_GT = 4,
+ CR_LTU = 8,
+ CR_GTU = 16
+};
+
+
+/* Convert the known results for EQ, LT, GT, LTU, GTU contained in
+ KNOWN_RESULT to a CONST_INT, based on the requested comparison CODE
+ For KNOWN_RESULT to make sense it should be either CR_EQ, or the
+ logical OR of one of (CR_LT, CR_GT) and one of (CR_LTU, CR_GTU).
+ For floating-point comparisons, assume that the operands were ordered. */
+
+static rtx
+comparison_result (enum rtx_code code, int known_results)
+{
+ /* If we reach here, EQUAL, OP0LT, OP0LTU, OP1LT, and OP1LTU are set
+ as appropriate. */
+ switch (code)
+ {
+ case EQ:
+ case UNEQ:
+ return (known_results & CR_EQ) ? const_true_rtx : const0_rtx;
+ case NE:
+ case LTGT:
+ return (known_results & CR_EQ) ? const0_rtx : const_true_rtx;
+
+ case LT:
+ case UNLT:
+ return (known_results & CR_LT) ? const_true_rtx : const0_rtx;
+ case GE:
+ case UNGE:
+ return (known_results & CR_LT) ? const0_rtx : const_true_rtx;
+
+ case GT:
+ case UNGT:
+ return (known_results & CR_GT) ? const_true_rtx : const0_rtx;
+ case LE:
+ case UNLE:
+ return (known_results & CR_GT) ? const0_rtx : const_true_rtx;
+
+ case LTU:
+ return (known_results & CR_LTU) ? const_true_rtx : const0_rtx;
+ case GEU:
+ return (known_results & CR_LTU) ? const0_rtx : const_true_rtx;
+
+ case GTU:
+ return (known_results & CR_GTU) ? const_true_rtx : const0_rtx;
+ case LEU:
+ return (known_results & CR_GTU) ? const0_rtx : const_true_rtx;
+
+ case ORDERED:
+ return const_true_rtx;
+ case UNORDERED:
+ return const0_rtx;
+ default:
+ gcc_unreachable ();
+ }
+}
+
/* Check if the given comparison (done in the given MODE) is actually a
tautology or a contradiction.
If no simplification is possible, this function returns zero.
enum machine_mode mode,
rtx op0, rtx op1)
{
- int equal, op0lt, op0ltu, op1lt, op1ltu;
rtx tem;
rtx trueop0;
rtx trueop1;
return const0_rtx;
/* For modes without NaNs, if the two operands are equal, we know the
- result except if they have side-effects. */
- if (! HONOR_NANS (GET_MODE (trueop0))
+ result except if they have side-effects. Even with NaNs we know
+ the result of unordered comparisons and, if signaling NaNs are
+ irrelevant, also the result of LT/GT/LTGT. */
+ if ((! HONOR_NANS (GET_MODE (trueop0))
+ || code == UNEQ || code == UNLE || code == UNGE
+ || ((code == LT || code == GT || code == LTGT)
+ && ! HONOR_SNANS (GET_MODE (trueop0))))
&& rtx_equal_p (trueop0, trueop1)
&& ! side_effects_p (trueop0))
- equal = 1, op0lt = 0, op0ltu = 0, op1lt = 0, op1ltu = 0;
+ return comparison_result (code, CR_EQ);
/* If the operands are floating-point constants, see if we can fold
the result. */
- else if (GET_CODE (trueop0) == CONST_DOUBLE
- && GET_CODE (trueop1) == CONST_DOUBLE
- && SCALAR_FLOAT_MODE_P (GET_MODE (trueop0)))
+ if (GET_CODE (trueop0) == CONST_DOUBLE
+ && GET_CODE (trueop1) == CONST_DOUBLE
+ && SCALAR_FLOAT_MODE_P (GET_MODE (trueop0)))
{
REAL_VALUE_TYPE d0, d1;
return 0;
}
- equal = REAL_VALUES_EQUAL (d0, d1);
- op0lt = op0ltu = REAL_VALUES_LESS (d0, d1);
- op1lt = op1ltu = REAL_VALUES_LESS (d1, d0);
+ return comparison_result (code,
+ (REAL_VALUES_EQUAL (d0, d1) ? CR_EQ :
+ REAL_VALUES_LESS (d0, d1) ? CR_LT : CR_GT));
}
/* Otherwise, see if the operands are both integers. */
- else if ((GET_MODE_CLASS (mode) == MODE_INT || mode == VOIDmode)
- && (GET_CODE (trueop0) == CONST_DOUBLE
- || GET_CODE (trueop0) == CONST_INT)
- && (GET_CODE (trueop1) == CONST_DOUBLE
- || GET_CODE (trueop1) == CONST_INT))
+ if ((GET_MODE_CLASS (mode) == MODE_INT || mode == VOIDmode)
+ && (GET_CODE (trueop0) == CONST_DOUBLE
+ || GET_CODE (trueop0) == CONST_INT)
+ && (GET_CODE (trueop1) == CONST_DOUBLE
+ || GET_CODE (trueop1) == CONST_INT))
{
int width = GET_MODE_BITSIZE (mode);
HOST_WIDE_INT l0s, h0s, l1s, h1s;
if (width != 0 && width <= HOST_BITS_PER_WIDE_INT)
h0u = h1u = 0, h0s = HWI_SIGN_EXTEND (l0s), h1s = HWI_SIGN_EXTEND (l1s);
- equal = (h0u == h1u && l0u == l1u);
- op0lt = (h0s < h1s || (h0s == h1s && l0u < l1u));
- op1lt = (h1s < h0s || (h1s == h0s && l1u < l0u));
- op0ltu = (h0u < h1u || (h0u == h1u && l0u < l1u));
- op1ltu = (h1u < h0u || (h1u == h0u && l1u < l0u));
+ if (h0u == h1u && l0u == l1u)
+ return comparison_result (code, CR_EQ);
+ else
+ {
+ int cr;
+ cr = (h0s < h1s || (h0s == h1s && l0u < l1u)) ? CR_LT : CR_GT;
+ cr |= (h0u < h1u || (h0u == h1u && l0u < l1u)) ? CR_LTU : CR_GTU;
+ return comparison_result (code, cr);
+ }
}
- /* Otherwise, there are some code-specific tests we can make. */
- else
+ /* Optimize comparisons with upper and lower bounds. */
+ if (SCALAR_INT_MODE_P (mode)
+ && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT
+ && GET_CODE (trueop1) == CONST_INT)
{
- /* Optimize comparisons with upper and lower bounds. */
- if (SCALAR_INT_MODE_P (mode)
- && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)
- {
- rtx mmin, mmax;
- int sign;
-
- if (code == GEU
- || code == LEU
- || code == GTU
- || code == LTU)
- sign = 0;
- else
- sign = 1;
-
- get_mode_bounds (mode, sign, mode, &mmin, &mmax);
-
- tem = NULL_RTX;
- switch (code)
- {
- case GEU:
- case GE:
- /* x >= min is always true. */
- if (rtx_equal_p (trueop1, mmin))
- tem = const_true_rtx;
- else
- break;
-
- case LEU:
- case LE:
- /* x <= max is always true. */
- if (rtx_equal_p (trueop1, mmax))
- tem = const_true_rtx;
- break;
-
- case GTU:
- case GT:
- /* x > max is always false. */
- if (rtx_equal_p (trueop1, mmax))
- tem = const0_rtx;
- break;
-
- case LTU:
- case LT:
- /* x < min is always false. */
- if (rtx_equal_p (trueop1, mmin))
- tem = const0_rtx;
- break;
+ int sign;
+ unsigned HOST_WIDE_INT nonzero = nonzero_bits (trueop0, mode);
+ HOST_WIDE_INT val = INTVAL (trueop1);
+ HOST_WIDE_INT mmin, mmax;
+
+ if (code == GEU
+ || code == LEU
+ || code == GTU
+ || code == LTU)
+ sign = 0;
+ else
+ sign = 1;
- default:
- break;
- }
- if (tem == const0_rtx
- || tem == const_true_rtx)
- return tem;
+ /* Get a reduced range if the sign bit is zero. */
+ if (nonzero <= (GET_MODE_MASK (mode) >> 1))
+ {
+ mmin = 0;
+ mmax = nonzero;
+ }
+ else
+ {
+ rtx mmin_rtx, mmax_rtx;
+ unsigned int sign_copies = num_sign_bit_copies (trueop0, mode);
+ get_mode_bounds (mode, sign, mode, &mmin_rtx, &mmax_rtx);
+
+ /* Since unsigned mmin will never be interpreted as negative, use
+ INTVAL (and an arithmetic right shift). */
+ mmin = INTVAL (mmin_rtx) >> (sign_copies - 1);
+ /* Since signed mmax will always be positive, use UINTVAL (and
+ a logical right shift). */
+ mmax = UINTVAL (mmax_rtx) >> (sign_copies - 1);
}
switch (code)
{
+ /* x >= y is always true for y <= mmin, always false for y > mmax. */
+ case GEU:
+ if ((unsigned HOST_WIDE_INT) val <= (unsigned HOST_WIDE_INT) mmin)
+ return const_true_rtx;
+ if ((unsigned HOST_WIDE_INT) val > (unsigned HOST_WIDE_INT) mmax)
+ return const0_rtx;
+ break;
+ case GE:
+ if (val <= mmin)
+ return const_true_rtx;
+ if (val > mmax)
+ return const0_rtx;
+ break;
+
+ /* x <= y is always true for y >= mmax, always false for y < mmin. */
+ case LEU:
+ if ((unsigned HOST_WIDE_INT) val >= (unsigned HOST_WIDE_INT) mmax)
+ return const_true_rtx;
+ if ((unsigned HOST_WIDE_INT) val < (unsigned HOST_WIDE_INT) mmin)
+ return const0_rtx;
+ break;
+ case LE:
+ if (val >= mmax)
+ return const_true_rtx;
+ if (val < mmin)
+ return const0_rtx;
+ break;
+
case EQ:
- if (trueop1 == const0_rtx && nonzero_address_p (op0))
+ /* x == y is always false for y out of range. */
+ if (val < mmin || val > mmax)
+ return const0_rtx;
+ break;
+
+ /* x > y is always false for y >= mmax, always true for y < mmin. */
+ case GTU:
+ if ((unsigned HOST_WIDE_INT) val >= (unsigned HOST_WIDE_INT) mmax)
+ return const0_rtx;
+ if ((unsigned HOST_WIDE_INT) val < (unsigned HOST_WIDE_INT) mmin)
+ return const_true_rtx;
+ break;
+ case GT:
+ if (val >= mmax)
+ return const0_rtx;
+ if (val < mmin)
+ return const_true_rtx;
+ break;
+
+ /* x < y is always false for y <= mmin, always true for y > mmax. */
+ case LTU:
+ if ((unsigned HOST_WIDE_INT) val <= (unsigned HOST_WIDE_INT) mmin)
+ return const0_rtx;
+ if ((unsigned HOST_WIDE_INT) val > (unsigned HOST_WIDE_INT) mmax)
+ return const_true_rtx;
+ break;
+ case LT:
+ if (val <= mmin)
return const0_rtx;
+ if (val > mmax)
+ return const_true_rtx;
break;
case NE:
- if (trueop1 == const0_rtx && nonzero_address_p (op0))
+ /* x != y is always true for y out of range. */
+ if (val < mmin || val > mmax)
return const_true_rtx;
break;
+ default:
+ break;
+ }
+ }
+
+ /* Optimize integer comparisons with zero. */
+ if (trueop1 == const0_rtx)
+ {
+ /* Some addresses are known to be nonzero. We don't know
+ their sign, but equality comparisons are known. */
+ if (nonzero_address_p (trueop0))
+ {
+ if (code == EQ || code == LEU)
+ return const0_rtx;
+ if (code == NE || code == GTU)
+ return const_true_rtx;
+ }
+
+ /* See if the first operand is an IOR with a constant. If so, we
+ may be able to determine the result of this comparison. */
+ if (GET_CODE (op0) == IOR)
+ {
+ rtx inner_const = avoid_constant_pool_reference (XEXP (op0, 1));
+ if (GET_CODE (inner_const) == CONST_INT && inner_const != const0_rtx)
+ {
+ int sign_bitnum = GET_MODE_BITSIZE (mode) - 1;
+ int has_sign = (HOST_BITS_PER_WIDE_INT >= sign_bitnum
+ && (INTVAL (inner_const)
+ & ((HOST_WIDE_INT) 1 << sign_bitnum)));
+
+ switch (code)
+ {
+ case EQ:
+ case LEU:
+ return const0_rtx;
+ case NE:
+ case GTU:
+ return const_true_rtx;
+ case LT:
+ case LE:
+ if (has_sign)
+ return const_true_rtx;
+ break;
+ case GT:
+ case GE:
+ if (has_sign)
+ return const0_rtx;
+ break;
+ default:
+ break;
+ }
+ }
+ }
+ }
+
+ /* Optimize comparison of ABS with zero. */
+ if (trueop1 == CONST0_RTX (mode)
+ && (GET_CODE (trueop0) == ABS
+ || (GET_CODE (trueop0) == FLOAT_EXTEND
+ && GET_CODE (XEXP (trueop0, 0)) == ABS)))
+ {
+ switch (code)
+ {
case LT:
/* Optimize abs(x) < 0.0. */
- if (trueop1 == CONST0_RTX (mode)
- && !HONOR_SNANS (mode)
+ if (!HONOR_SNANS (mode)
&& (!INTEGRAL_MODE_P (mode)
|| (!flag_wrapv && !flag_trapv && flag_strict_overflow)))
{
- tem = GET_CODE (trueop0) == FLOAT_EXTEND ? XEXP (trueop0, 0)
- : trueop0;
- if (GET_CODE (tem) == ABS)
- {
- if (INTEGRAL_MODE_P (mode)
- && (issue_strict_overflow_warning
- (WARN_STRICT_OVERFLOW_CONDITIONAL)))
- warning (OPT_Wstrict_overflow,
- ("assuming signed overflow does not occur when "
- "assuming abs (x) < 0 is false"));
- return const0_rtx;
- }
+ if (INTEGRAL_MODE_P (mode)
+ && (issue_strict_overflow_warning
+ (WARN_STRICT_OVERFLOW_CONDITIONAL)))
+ warning (OPT_Wstrict_overflow,
+ ("assuming signed overflow does not occur when "
+ "assuming abs (x) < 0 is false"));
+ return const0_rtx;
}
-
- /* Optimize popcount (x) < 0. */
- if (GET_CODE (trueop0) == POPCOUNT && trueop1 == const0_rtx)
- return const_true_rtx;
break;
case GE:
/* Optimize abs(x) >= 0.0. */
- if (trueop1 == CONST0_RTX (mode)
- && !HONOR_NANS (mode)
+ if (!HONOR_NANS (mode)
&& (!INTEGRAL_MODE_P (mode)
|| (!flag_wrapv && !flag_trapv && flag_strict_overflow)))
{
- tem = GET_CODE (trueop0) == FLOAT_EXTEND ? XEXP (trueop0, 0)
- : trueop0;
- if (GET_CODE (tem) == ABS)
- {
- if (INTEGRAL_MODE_P (mode)
- && (issue_strict_overflow_warning
- (WARN_STRICT_OVERFLOW_CONDITIONAL)))
- warning (OPT_Wstrict_overflow,
- ("assuming signed overflow does not occur when "
- "assuming abs (x) >= 0 is true"));
- return const_true_rtx;
- }
+ if (INTEGRAL_MODE_P (mode)
+ && (issue_strict_overflow_warning
+ (WARN_STRICT_OVERFLOW_CONDITIONAL)))
+ warning (OPT_Wstrict_overflow,
+ ("assuming signed overflow does not occur when "
+ "assuming abs (x) >= 0 is true"));
+ return const_true_rtx;
}
-
- /* Optimize popcount (x) >= 0. */
- if (GET_CODE (trueop0) == POPCOUNT && trueop1 == const0_rtx)
- return const_true_rtx;
break;
case UNGE:
/* Optimize ! (abs(x) < 0.0). */
- if (trueop1 == CONST0_RTX (mode))
- {
- tem = GET_CODE (trueop0) == FLOAT_EXTEND ? XEXP (trueop0, 0)
- : trueop0;
- if (GET_CODE (tem) == ABS)
- return const_true_rtx;
- }
- break;
+ return const_true_rtx;
default:
break;
}
-
- return 0;
}
- /* If we reach here, EQUAL, OP0LT, OP0LTU, OP1LT, and OP1LTU are set
- as appropriate. */
- switch (code)
- {
- case EQ:
- case UNEQ:
- return equal ? const_true_rtx : const0_rtx;
- case NE:
- case LTGT:
- return ! equal ? const_true_rtx : const0_rtx;
- case LT:
- case UNLT:
- return op0lt ? const_true_rtx : const0_rtx;
- case GT:
- case UNGT:
- return op1lt ? const_true_rtx : const0_rtx;
- case LTU:
- return op0ltu ? const_true_rtx : const0_rtx;
- case GTU:
- return op1ltu ? const_true_rtx : const0_rtx;
- case LE:
- case UNLE:
- return equal || op0lt ? const_true_rtx : const0_rtx;
- case GE:
- case UNGE:
- return equal || op1lt ? const_true_rtx : const0_rtx;
- case LEU:
- return equal || op0ltu ? const_true_rtx : const0_rtx;
- case GEU:
- return equal || op1ltu ? const_true_rtx : const0_rtx;
- case ORDERED:
- return const_true_rtx;
- case UNORDERED:
- return const0_rtx;
- default:
- gcc_unreachable ();
- }
+ return 0;
}
\f
/* Simplify CODE, an operation with result mode MODE and three operands,
projects / thirdparty / gcc.git / commitdiff
