Hi!
OImode/XImode on i?86/x86_64 are not <= MAX_BITSIZE_MODE_ANY_INT, because
they are never used for integer arithmetics (and there is no way
to represent all their values in RTL if not using CONST_WIDE_INT).
As the following testcase shows, simplify_immed_subreg can be called
with such modes though, e.g. trying to forward propagate a CONST_VECTOR
(i?86/x86_64 handles all zeros and all ones as CONST_VECTORs that can appear
in the IL directly) into a SUBREG_REG.
The following patch instead of ICE handles the most common cases (all 0
and all 1 CONST_VECTORs) and returns NULL otherwise.
Before wide-int got merged, the testcase worked, though the code didn't
bother checking anything, just created 0 or constm1_rtx for the two cases
that could happen and if something else appeared, could just return what
matched low TImode (or DImode for -m32).
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2014-11-18 Jakub Jelinek <ja...@redhat.com>
PR target/63910
* simplify-rtx.c (simplify_immed_subreg): For integer modes
wider than MAX_BITSIZE_MODE_ANY_INT, handle all zeros and all ones
and for other values return NULL_RTX.
* gcc.target/i386/pr63910.c: New test.
--- gcc/simplify-rtx.c.jj 2014-11-11 00:06:19.000000000 +0100
+++ gcc/simplify-rtx.c 2014-11-18 10:17:01.198668555 +0100
@@ -5505,6 +5505,21 @@ simplify_immed_subreg (machine_mode oute
HOST_WIDE_INT tmp[MAX_BITSIZE_MODE_ANY_INT /
HOST_BITS_PER_WIDE_INT];
wide_int r;
+ if (GET_MODE_PRECISION (outer_submode) > MAX_BITSIZE_MODE_ANY_INT)
+ {
+ /* Handle just all zeros and all ones CONST_VECTORs in
+ this case. */
+ if ((vp[0] & value_mask) == 0)
+ elems[elem] = const0_rtx;
+ else if ((vp[0] & value_mask) == value_mask)
+ elems[elem] = constm1_rtx;
+ else
+ return NULL_RTX;
+ for (i = value_bit; i < elem_bitsize; i += value_bit)
+ if ((vp[i / value_bit] & value_mask) != (vp[0] & value_mask))
+ return NULL_RTX;
+ break;
+ }
for (u = 0; u < units; u++)
{
unsigned HOST_WIDE_INT buf = 0;
@@ -5516,8 +5531,6 @@ simplify_immed_subreg (machine_mode oute
tmp[u] = buf;
base += HOST_BITS_PER_WIDE_INT;
}
- gcc_assert (GET_MODE_PRECISION (outer_submode)
- <= MAX_BITSIZE_MODE_ANY_INT);
r = wide_int::from_array (tmp, units,
GET_MODE_PRECISION (outer_submode));
elems[elem] = immed_wide_int_const (r, outer_submode);
--- gcc/testsuite/gcc.target/i386/pr63910.c.jj 2014-11-18 10:12:24.282659318
+0100
+++ gcc/testsuite/gcc.target/i386/pr63910.c 2014-11-18 10:12:00.000000000
+0100
@@ -0,0 +1,12 @@
+/* PR target/63910 */
+/* { dg-do compile } */
+/* { dg-options "-O -mstringop-strategy=vector_loop -mavx512f" } */
+
+extern void bar (float *c);
+
+void
+foo (void)
+{
+ float c[1024] = { };
+ bar (c);
+}
Jakub
