https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95115
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
Target|riscv64-unknown-linux-gnu |
Summary|[10 Regression] RISC-V 64: |RISC-V 64: inf/inf division
|inf/inf division optimized |optimized out, invalid
|out, invalid operation not |operation not raised
|raised |
Last reconfirmed| |2020-05-14
Ever confirmed|0 |1
Component|target |middle-end
Build|riscv64-unknown-linux-gnu |
Host|riscv64-unknown-linux-gnu |
Status|UNCONFIRMED |NEW
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
(simplify
(rdiv @0 @0)
(if (FLOAT_TYPE_P (type)
&& ! HONOR_NANS (type)
&& ! HONOR_INFINITIES (type))
{ build_one_cst (type); }))
so that's not it, possibly constant folding instead in const_binop.
There we only have
1276 /* Don't perform operation if we honor signaling NaNs and
1277 either operand is a signaling NaN. */
1278 if (HONOR_SNANS (mode)
1279 && (REAL_VALUE_ISSIGNALING_NAN (d1)
1280 || REAL_VALUE_ISSIGNALING_NAN (d2)))
1281 return NULL_TREE;
and
1283 /* Don't perform operation if it would raise a division
(gdb)
1284 by zero exception. */
1285 if (code == RDIV_EXPR
1286 && real_equal (&d2, &dconst0)
1287 && (flag_trapping_math || ! MODE_HAS_INFINITIES (mode)))
1288 return NULL_TREE;
which both don't trigger. Afterwards
1309 inexact = real_arithmetic (&value, code, &d1, &d2);
even returns false and the result is a qNaN.
For the specific regression in this bug we now simply are able to
turn
return u.x/v.x;
into a division of two constants. That's nothing we're going to "fix",
so we have to fix the above instead which is a much older issue.
