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| author | Richard Sandiford <richard.sandiford@linaro.org> | 2017-08-30 11:19:39 +0000 |
|---|---|---|
| committer | Richard Sandiford <rsandifo@gcc.gnu.org> | 2017-08-30 11:19:39 +0000 |
| commit | db61b7f923b769142156eab047c94b04bb7adaae (patch) | |
| tree | 522f1a6eed83a6d3571b7d5746f0fbeb9c488141 /gcc/explow.c | |
| parent | b397965cae46d88d4c274fb2ecdde9a4714a4e6a (diff) | |
| download | gcc-db61b7f923b769142156eab047c94b04bb7adaae.zip gcc-db61b7f923b769142156eab047c94b04bb7adaae.tar.gz gcc-db61b7f923b769142156eab047c94b04bb7adaae.tar.bz2 | |
[66/77] Use scalar_mode for constant integers
This patch treats the mode associated with an integer constant as a
scalar_mode. We can't use the more natural-sounding scalar_int_mode
because we also use (const_int 0) for bounds-checking modes. (It might
be worth adding a bounds-specific code instead, but that's for another
day.)
This exposes a latent bug in simplify_immed_subreg, which for
vectors of CONST_WIDE_INTs would pass the vector mode rather than
the element mode to rtx_mode_t.
I think the:
/* We can get a 0 for an error mark. */
|| GET_MODE_CLASS (mode) == MODE_VECTOR_INT
|| GET_MODE_CLASS (mode) == MODE_VECTOR_FLOAT
in immed_double_const is dead. trunc_int_mode (via gen_int_mode)
would go on to ICE if the mode fitted in a HWI, and surely plenty
of other code would be confused to see a const_int be interpreted
as a vector. We should instead be using CONST0_RTX (mode) if we
need a safe constant for a particular mode.
We didn't try to make these functions take scalar_mode arguments
because in many cases that would be too invasive at this stage.
Maybe it would become feasible in future. Also, the long-term
direction should probably be to add modes to constant integers
rather than have then as VOIDmode odd-ones-out. That would remove
the need for rtx_mode_t and thus remove the question whether they
should use scalar_int_mode, scalar_mode or machine_mode.
The patch also uses scalar_mode for the CONST_DOUBLE handling
in loc_descriptor. In that case the mode can legitimately be
either floating-point or integral.
2017-08-30 Richard Sandiford <richard.sandiford@linaro.org>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>
gcc/
* emit-rtl.c (immed_double_const): Use is_a <scalar_mode> instead
of separate mode class checks. Do not allow vector modes here.
(immed_wide_int_const): Use as_a <scalar_mode>.
* explow.c (trunc_int_for_mode): Likewise.
* rtl.h (wi::int_traits<rtx_mode_t>::get_precision): Likewise.
(wi::shwi): Likewise.
(wi::min_value): Likewise.
(wi::max_value): Likewise.
* dwarf2out.c (loc_descriptor): Likewise.
* simplify-rtx.c (simplify_immed_subreg): Fix rtx_mode_t argument
for CONST_WIDE_INT.
Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r251517
Diffstat (limited to 'gcc/explow.c')
| -rw-r--r-- | gcc/explow.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/gcc/explow.c b/gcc/explow.c index 5079629..ee20969 100644 --- a/gcc/explow.c +++ b/gcc/explow.c @@ -49,14 +49,16 @@ static rtx break_out_memory_refs (rtx); HOST_WIDE_INT trunc_int_for_mode (HOST_WIDE_INT c, machine_mode mode) { - int width = GET_MODE_PRECISION (mode); + /* Not scalar_int_mode because we also allow pointer bound modes. */ + scalar_mode smode = as_a <scalar_mode> (mode); + int width = GET_MODE_PRECISION (smode); /* You want to truncate to a _what_? */ gcc_assert (SCALAR_INT_MODE_P (mode) || POINTER_BOUNDS_MODE_P (mode)); /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */ - if (mode == BImode) + if (smode == BImode) return c & 1 ? STORE_FLAG_VALUE : 0; /* Sign-extend for the requested mode. */ |