On Mon, Dec 02, 2013 at 12:05:57PM +0100, Richard Biener wrote:
>
> The following fixes a bug in update_address_taken which fails
> to reset debug stmts which take the address of a decl we will
> rewrite into SSA form. Our verifiers don't catch this because
> of an early out in the operand scanner which doesn't work in
> the specific case of LTO profiledbootstrap (or because we
> don't have more specific checking for this case).
>
> Fixed like the following.
>
> LTO profiledbootstrapped on x86_64-unknown-linux-gnu, regular
> bootstrap & regtest still running.
Taking address of a decl that is no longer addressable in debug stmts
is correct, that is how we generate DW_OP_GNU_implicit_ptr.
So I think this patch is going to cause huge amount of debug info quality
regressions.
> 2013-12-02 Richard Biener <rguent...@suse.de>
>
> PR middle-end/59199
> * tree-ssa.c (execute_update_addresses_taken): Reset debug
> stmts that take the address of a no longer addressable decl.
>
> Index: gcc/tree-ssa.c
> ===================================================================
> *** gcc/tree-ssa.c (revision 205528)
> --- gcc/tree-ssa.c (working copy)
> *************** execute_update_addresses_taken (void)
> *** 1651,1661 ****
> {
> tree *valuep = gimple_debug_bind_get_value_ptr (stmt);
> tree decl;
> ! maybe_rewrite_mem_ref_base (valuep, suitable_for_renaming);
> ! decl = non_rewritable_mem_ref_base (*valuep);
> if (decl
> && bitmap_bit_p (suitable_for_renaming, DECL_UID (decl)))
> gimple_debug_bind_reset_value (stmt);
> }
>
> if (gimple_references_memory_p (stmt)
> --- 1651,1666 ----
> {
> tree *valuep = gimple_debug_bind_get_value_ptr (stmt);
> tree decl;
> ! if (TREE_CODE (*valuep) == ADDR_EXPR)
> ! decl = get_base_address (TREE_OPERAND (*valuep, 0));
> ! else
> ! decl = non_rewritable_mem_ref_base (*valuep);
> if (decl
> + && DECL_P (decl)
> && bitmap_bit_p (suitable_for_renaming, DECL_UID (decl)))
> gimple_debug_bind_reset_value (stmt);
> + else
> + maybe_rewrite_mem_ref_base (valuep, suitable_for_renaming);
> }
>
> if (gimple_references_memory_p (stmt)
Jakub
