Ping.
https://gcc.gnu.org/ml/gcc-patches/2015-10/msg01350.html
and the backport for 4.9/5
https://gcc.gnu.org/ml/gcc-patches/2015-10/msg01351.html
Thanks,
Kyrill
On 14/10/15 13:23, Kyrill Tkachov wrote:
Hi all,
This patch fixes the referenced PR by rewriting the vfp3_const_double_for_bits
function in arm.c
The function is supposed to accept positive CONST_DOUBLE rtxes whose value is
an exact power of 2
and whose log2 is between 1 and 32. That is values like 2.0, 4.0, 8.9, 16.0
etc...
The current implementation seems to have been written under the assumption that
exact_real_truncate returns
false if the input value is not an exact integer, whereas in fact
exact_real_truncate returns false if the
truncation operation was not exact, which are different things. This would lead
the function to accept any
CONST_DOUBLE that can truncate to a power of 2, such as 4.9, 16.2 etc.
In any case, I've rewritten this function and used the real_isinteger predicate
to check if the real value
is an exact integer.
The testcase demonstrates the kind of wrong code that this patch addresses.
This bug appears on GCC 5 and 4.9 as well, but due to the recent introduction
of CONST_DOUBLE_REAL_VALUE
this patch doesn't apply on those branches. I will soon post the backportable
variant.
Bootstrapped and tested on arm-none-linux-gnueabihf.
Ok for trunk?
Thanks,
Kyrill
2015-10-12 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
PR target/67929
* config/arm/arm.c (vfp3_const_double_for_bits): Rewrite.
* config/arm/constraints.md (Dp): Update callsite.
* config/arm/predicates.md (const_double_vcvt_power_of_two): Likewise.
2015-10-12 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
PR target/67929
* gcc.target/arm/pr67929_1.c: New test.
