diff options
Diffstat (limited to 'gcc/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 94 |
1 files changed, 87 insertions, 7 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index c338b665ca0..3e0bdbfa27a 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -775,19 +775,99 @@ simplify_unary_operation (enum rtx_code code, enum machine_mode mode, else if (GET_CODE (trueop) == CONST_DOUBLE && GET_MODE_CLASS (GET_MODE (trueop)) == MODE_FLOAT && GET_MODE_CLASS (mode) == MODE_INT - && width <= HOST_BITS_PER_WIDE_INT && width > 0) + && width <= 2*HOST_BITS_PER_WIDE_INT && width > 0) { - HOST_WIDE_INT i; - REAL_VALUE_TYPE d; - REAL_VALUE_FROM_CONST_DOUBLE (d, trueop); + /* Although the overflow semantics of RTL's FIX and UNSIGNED_FIX + operators are intentionally left unspecified (to ease implemention + by target backends), for consistency, this routine implements the + same semantics for constant folding as used by the middle-end. */ + + HOST_WIDE_INT xh, xl, th, tl; + REAL_VALUE_TYPE x, t; + REAL_VALUE_FROM_CONST_DOUBLE (x, trueop); switch (code) { - case FIX: i = REAL_VALUE_FIX (d); break; - case UNSIGNED_FIX: i = REAL_VALUE_UNSIGNED_FIX (d); break; + case FIX: + if (REAL_VALUE_ISNAN (x)) + return const0_rtx; + + /* Test against the signed upper bound. */ + if (width > HOST_BITS_PER_WIDE_INT) + { + th = ((unsigned HOST_WIDE_INT) 1 + << (width - HOST_BITS_PER_WIDE_INT - 1)) - 1; + tl = -1; + } + else + { + th = 0; + tl = ((unsigned HOST_WIDE_INT) 1 << (width - 1)) - 1; + } + real_from_integer (&t, VOIDmode, tl, th, 0); + if (REAL_VALUES_LESS (t, x)) + { + xh = th; + xl = tl; + break; + } + + /* Test against the signed lower bound. */ + if (width > HOST_BITS_PER_WIDE_INT) + { + th = (HOST_WIDE_INT) -1 << (width - HOST_BITS_PER_WIDE_INT - 1); + tl = 0; + } + else + { + th = -1; + tl = (HOST_WIDE_INT) -1 << (width - 1); + } + real_from_integer (&t, VOIDmode, tl, th, 0); + if (REAL_VALUES_LESS (x, t)) + { + xh = th; + xl = tl; + break; + } + REAL_VALUE_TO_INT (&xl, &xh, x); + break; + + case UNSIGNED_FIX: + if (REAL_VALUE_ISNAN (x) || REAL_VALUE_NEGATIVE (x)) + return const0_rtx; + + /* Test against the unsigned upper bound. */ + if (width == 2*HOST_BITS_PER_WIDE_INT) + { + th = -1; + tl = -1; + } + else if (width >= HOST_BITS_PER_WIDE_INT) + { + th = ((unsigned HOST_WIDE_INT) 1 + << (width - HOST_BITS_PER_WIDE_INT)) - 1; + tl = -1; + } + else + { + th = 0; + tl = ((unsigned HOST_WIDE_INT) 1 << width) - 1; + } + real_from_integer (&t, VOIDmode, tl, th, 1); + if (REAL_VALUES_LESS (t, x)) + { + xh = th; + xl = tl; + break; + } + + REAL_VALUE_TO_INT (&xl, &xh, x); + break; + default: abort (); } - return gen_int_mode (i, mode); + return immed_double_const (xl, xh, mode); } /* This was formerly used only for non-IEEE float. |