On Wed, 11 Dec 2013, Jakub Jelinek wrote:
> Hi!
>
> As discussed in the PR, range info as well as alignment info for pointers
> can be position dependent, can be e.g. computed from VRP ASSERT_EXPRs,
> so we can't blindly propagate it to SSA_NAMEs that the SSA_NAME with range
> info has been set to. The following patch limits that to SSA_NAMEs defined
> within the same bb, in that case it should be safe.
>
> Also, the patch makes determine_value_range more robust, insert of asserting
> it will just punt and use solely range info of var, rather than also
> considering ranges of PHI results. If VR_UNDEFINED comes into play, range
> info can be weird (of course on undefined behavior only code, but we
> shouldn't ICE on it).
>
> Either of these changes fixes the ICE on it's own.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
Thanks,
Richard.
> 2013-12-11 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/59417
> * tree-ssa-copy.c (fini_copy_prop): If copy_of[i].value is defined
> in a different bb rhan var, only duplicate points-to info and
> not alignment info and don't duplicate range info.
> * tree-ssa-loop-niter.c (determine_value_range): Instead of
> assertion failure handle inconsistencies in range info by only
> using var's range info and not PHI result range infos.
>
> * gcc.c-torture/compile/pr59417.c: New test.
>
> --- gcc/tree-ssa-copy.c.jj 2013-12-10 08:52:13.000000000 +0100
> +++ gcc/tree-ssa-copy.c 2013-12-10 17:55:16.819293842 +0100
> @@ -567,14 +567,28 @@ fini_copy_prop (void)
> if (copy_of[i].value != var
> && TREE_CODE (copy_of[i].value) == SSA_NAME)
> {
> + basic_block copy_of_bb
> + = gimple_bb (SSA_NAME_DEF_STMT (copy_of[i].value));
> + basic_block var_bb = gimple_bb (SSA_NAME_DEF_STMT (var));
> if (POINTER_TYPE_P (TREE_TYPE (var))
> && SSA_NAME_PTR_INFO (var)
> && !SSA_NAME_PTR_INFO (copy_of[i].value))
> - duplicate_ssa_name_ptr_info (copy_of[i].value,
> - SSA_NAME_PTR_INFO (var));
> + {
> + duplicate_ssa_name_ptr_info (copy_of[i].value,
> + SSA_NAME_PTR_INFO (var));
> + /* Points-to information is cfg insensitive,
> + but alignment info might be cfg sensitive, if it
> + e.g. is derived from VRP derived non-zero bits.
> + So, do not copy alignment info if the two SSA_NAMEs
> + aren't defined in the same basic block. */
> + if (var_bb != copy_of_bb)
> + mark_ptr_info_alignment_unknown
> + (SSA_NAME_PTR_INFO (copy_of[i].value));
> + }
> else if (!POINTER_TYPE_P (TREE_TYPE (var))
> && SSA_NAME_RANGE_INFO (var)
> - && !SSA_NAME_RANGE_INFO (copy_of[i].value))
> + && !SSA_NAME_RANGE_INFO (copy_of[i].value)
> + && var_bb == copy_of_bb)
> duplicate_ssa_name_range_info (copy_of[i].value,
> SSA_NAME_RANGE_TYPE (var),
> SSA_NAME_RANGE_INFO (var));
> --- gcc/tree-ssa-loop-niter.c.jj 2013-12-02 23:34:02.000000000 +0100
> +++ gcc/tree-ssa-loop-niter.c 2013-12-10 17:59:07.744105878 +0100
> @@ -173,7 +173,15 @@ determine_value_range (struct loop *loop
> {
> minv = minv.max (minc, TYPE_UNSIGNED (type));
> maxv = maxv.min (maxc, TYPE_UNSIGNED (type));
> - gcc_assert (minv.cmp (maxv, TYPE_UNSIGNED (type)) <= 0);
> + /* If the PHI result range are inconsistent with
> + the VAR range, give up on looking at the PHI
> + results. This can happen if VR_UNDEFINED is
> + involved. */
> + if (minv.cmp (maxv, TYPE_UNSIGNED (type)) > 0)
> + {
> + rtype = get_range_info (var, &minv, &maxv);
> + break;
> + }
> }
> }
> }
> --- gcc/testsuite/gcc.c-torture/compile/pr59417.c.jj 2013-12-10
> 17:59:29.235996171 +0100
> +++ gcc/testsuite/gcc.c-torture/compile/pr59417.c 2013-12-09
> 16:26:53.000000000 +0100
> @@ -0,0 +1,39 @@
> +/* PR tree-optimization/59417 */
> +
> +int a, b, d;
> +short c;
> +
> +void
> +f (void)
> +{
> + if (b)
> + {
> + int *e;
> +
> + if (d)
> + {
> + for (; b; a++)
> + lbl1:
> + d = 0;
> +
> + for (; d <= 1; d++)
> + {
> + int **q = &e;
> + for (**q = 0; **q <= 0; **q++)
> + d = 0;
> + }
> + }
> + }
> +
> + else
> + {
> + int t;
> + for (c = 0; c < 77; c++)
> + for (c = 0; c < 46; c++);
> + for (; t <= 0; t++)
> + lbl2:
> + ;
> + goto lbl1;
> + }
> + goto lbl2;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
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