On Mon, Feb 20, 2017 at 07:24:50PM +0100, Jakub Jelinek wrote:
> On Thu, Feb 16, 2017 at 05:46:30PM +0000, Segher Boessenkool wrote:
> > The testcases pr59833.c and pr61441.c check whether signaling NaNs as
> > input to some operation result in quiet NaNs. Without -fsignaling-nans
> > this is not guaranteed to happen. So, this patch add this option to
> > these testcases.
> >
> > Tested on powerpc64-linux {-m32,-m64}, on aarch64-linux, and on
> > x86_64-linux (where there is no issignaling, huh -- I tested on gcc20).
>
> pr61441.c now fails since your change on i?86-linux (and x86_64-linux -m32).
> Before combine we have:
> (insn 6 5 7 2 (set (reg:DF 89 [ x ])
> (float_extend:DF (mem/u/c:SF (symbol_ref/u:SI ("*.LC0") [flags 0x2])
> [1 S4 A32]))) "pr61441.c":12 152 {*extendsfdf2}
> (expr_list:REG_EQUAL (const_double:DF +SNaN [+SNaN])
> (nil)))
> (insn 7 6 8 2 (set (mem:DF (pre_dec:SI (reg/f:SI 7 sp)) [2 S8 A64])
> (reg:DF 89 [ x ])) "pr61441.c":13 119 {*pushdf}
> (expr_list:REG_DEAD (reg:DF 89 [ x ])
> (expr_list:REG_ARGS_SIZE (const_int 16 [0x10])
> (nil))))
> (not sure if that REG_EQUAL is not already invalid for -fsignaling-nans),
> and combine turns that into:
> (insn 7 6 8 2 (set (mem:DF (pre_dec:SI (reg/f:SI 7 sp)) [2 S8 A64])
> (const_double:DF +SNaN [+SNaN])) "pr61441.c":13 119 {*pushdf}
> (expr_list:REG_ARGS_SIZE (const_int 16 [0x10])
> (nil)))
> which doesn't drop the signal bit.
I have a patch, I'll bootstrap/regtest it and post afterwards.
Jakub
