Hi!
The following testcase ICEs, because we have *pbitsize 65 and
lang_hooks.types.type_for_size returns NULL for that. The following patch
punts in that case, but makes sure we punt before overwriting *exp_, because
the caller uses it regardless of whether decode_field_reference returns NULL
or not.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
David has proposed to also change c_common_type_for_size to handle the 65 to
127 bit bitsizes, but that looks too risky for me for GCC 9, although if you
think it can go in now, David has a patch for that.
2019-02-20 Jakub Jelinek <ja...@redhat.com>
David Malcolm <dmalc...@redhat.com>
PR middle-end/89091
* fold-const.c (decode_field_reference): Return NULL_TREE if
lang_hooks.types.type_for_size returns NULL. Check it before
overwriting *exp_. Use return NULL_TREE instead of return 0.
* gcc.dg/torture/pr89091.c: New test.
--- gcc/fold-const.c.jj 2019-02-14 10:24:16.300632811 +0100
+++ gcc/fold-const.c 2019-02-20 15:52:35.476932131 +0100
@@ -4280,7 +4280,7 @@ decode_field_reference (location_t loc,
There are problems with FP fields since the type_for_size call
below can fail for, e.g., XFmode. */
if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
- return 0;
+ return NULL_TREE;
/* We are interested in the bare arrangement of bits, so strip everything
that doesn't affect the machine mode. However, record the type of the
@@ -4296,7 +4296,7 @@ decode_field_reference (location_t loc,
exp = TREE_OPERAND (exp, 0);
STRIP_NOPS (exp); STRIP_NOPS (and_mask);
if (TREE_CODE (and_mask) != INTEGER_CST)
- return 0;
+ return NULL_TREE;
}
poly_int64 poly_bitsize, poly_bitpos;
@@ -4312,7 +4312,11 @@ decode_field_reference (location_t loc,
|| (! AGGREGATE_TYPE_P (TREE_TYPE (inner))
&& compare_tree_int (TYPE_SIZE (TREE_TYPE (inner)),
*pbitpos + *pbitsize) < 0))
- return 0;
+ return NULL_TREE;
+
+ unsigned_type = lang_hooks.types.type_for_size (*pbitsize, 1);
+ if (unsigned_type == NULL_TREE)
+ return NULL_TREE;
*exp_ = exp;
@@ -4323,7 +4327,6 @@ decode_field_reference (location_t loc,
*punsignedp = TYPE_UNSIGNED (outer_type);
/* Compute the mask to access the bitfield. */
- unsigned_type = lang_hooks.types.type_for_size (*pbitsize, 1);
precision = TYPE_PRECISION (unsigned_type);
mask = build_int_cst_type (unsigned_type, -1);
--- gcc/testsuite/gcc.dg/torture/pr89091.c.jj 2019-02-20 15:55:54.604694453
+0100
+++ gcc/testsuite/gcc.dg/torture/pr89091.c 2019-02-20 15:55:18.186294196
+0100
@@ -0,0 +1,10 @@
+/* PR middle-end/89091 */
+/* { dg-do compile { target int128 } } */
+
+struct S { unsigned __int128 s : 65; };
+
+int
+foo (struct S *x, int y)
+{
+ return y && x->s;
+}
Jakub
