On 05/21/12 11:03, Richard Guenther wrote:
Hmm - I think this papers over the issue that the CONSTRUCTOR is not
properly gimplified - it still contains a TARGET_EXPR which is not valid GIMPLE.
Why is that TARGET_EXPR not gimplified?
As far as I can make out, it just doesn't look inside the constructor.
0 gimplify_expr (expr_p=0xb7e90394, pre_p=0xbfffe514, post_p=0xbfffd08c,
gimple_test_f=0x84b0a80 <is_gimple_min_lval(tree_node*)>, fallback=3) at
../../src/gcc/gimplify.c:7356
#1 0x084f5882 in gimplify_compound_lval (expr_p=0xb7e9cb94, pre_p=0xbfffe514,
post_p=0xbfffd08c, fallback=1)
at ../../src/gcc/gimplify.c:2259
#2 0x08519878 in gimplify_expr (expr_p=0xb7e9cb94, pre_p=0xbfffe514,
post_p=0xbfffd08c,
gimple_test_f=0x84eaf9f <is_gimple_reg_rhs_or_call(tree)>, fallback=1) at
../../src/gcc/gimplify.c:7081
#3 0x085087f7 in gimplify_modify_expr (expr_p=0xbfffd6d0, pre_p=0xbfffe514,
post_p=0xbfffd08c, want_value=false)
at ../../src/gcc/gimplify.c:4843
The switch case at that stack frame is for CONSTRUCTORs. It has the comment:
/* Don't reduce this in place; let gimplify_init_constructor work its
magic. Buf if we're just elaborating this for side effects, just
gimplify any element that has side-effects. */
But we never enter G_I_C before the ICE.
On the second time we get here, fallback has the value 1 at that point
(fb_rvalue), so neither if condition is satisified, and we end up at
ret = GS_ALL_DONE;
we then proceed down to enter:
else if ((fallback & fb_rvalue) && is_gimple_reg_rhs_or_call (*expr_p))
{
/* An rvalue will do. Assign the gimplified expression into a
new temporary TMP and replace the original expression with
TMP. First, make sure that the expression has a type so that
it can be assigned into a temporary. */
gcc_assert (!VOID_TYPE_P (TREE_TYPE (*expr_p)));
*expr_p = get_formal_tmp_var (*expr_p, pre_p);
}
and ICE inside GFTV when it attempts to generate the hash.
AFAICT, changing the test case to:
char *str = ((union {const char * _q; char * _nq;})
((const char *)((num_string)
->string.str)))._nq;
(i.e. removing the stmt-expr) results in the same logical flow as above, but
there's no TARGET_EXPR inside the constructor.
I'm not sure how it's supposed to work, so I'm a little lost.
