On 10/21/21 3:02 PM, Andrew MacLeod wrote:
As I'm tweaking installing ranger as the VRP2 pass, I am getting a
stage 2 bootstrap failure now:
In file included from
/opt/notnfs/amacleod/master/gcc/gcc/fortran/trans-decl.c:28:
/opt/notnfs/amacleod/master/gcc/gcc/tree.h: In function ‘void
gfc_conv_cfi_to_gfc(stmtblock_t*, stmtblock_t*, tree, tree,
gfc_symbol*)’:
/opt/notnfs/amacleod/master/gcc/gcc/tree.h:244:56: error: ‘rank’ may
be used uninitialized in this function [-Werror=maybe-uninitialized]
244 | #define TREE_CODE(NODE) ((enum tree_code) (NODE)->base.code)
| ^~~~
/opt/notnfs/amacleod/master/gcc/gcc/fortran/trans-decl.c:6671:8: note:
‘rank’ was declared here
6671 | tree rank, idx, etype, tmp, tmp2, size_var = NULL_TREE;
| ^~~~
cc1plus: all warnings being treated as errors
make[3]: *** [Makefile:1136: fortran/trans-decl.o] Error 1
looking at that function, in the middle I see:
if (sym->as->rank < 0)
{
/* Set gfc->dtype.rank, if assumed-rank. */
rank = gfc_get_cfi_desc_rank (cfi);
gfc_add_modify (&block, gfc_conv_descriptor_rank (gfc_desc), rank);
}
else if (!GFC_DESCRIPTOR_TYPE_P (TREE_TYPE (gfc_desc)))
/* In that case, the CFI rank and the declared rank can differ. */
rank = gfc_get_cfi_desc_rank (cfi);
else
rank = build_int_cst (signed_char_type_node, sym->as->rank);
so rank is set on all paths here. However, stepping back a bit,
earlier in the function I see:
if (!sym->attr.dimension || !GFC_DESCRIPTOR_TYPE_P (TREE_TYPE
(gfc_desc)))
{
tmp = gfc_get_cfi_desc_base_addr (cfi);
gfc_add_modify (&block, gfc_desc,
fold_convert (TREE_TYPE (gfc_desc), tmp));
if (!sym->attr.dimension)
goto done;
}
The done: label occurs *after* that block of initialization code, and
bit furtehr down , I see this:
gfc_add_modify (&loop_body, tmpidx, idx);
stmtblock_t inner_loop;
gfc_init_block (&inner_loop);
tree dim = gfc_create_var (TREE_TYPE (rank), "dim");
I cannot convince myself by looking at the intervening code that this
can not be executed along this path. Perhaps someone more familiar
with the code can check it out. However, It seems worthwhile to at
least initialize rank to NULL_TREE, thus we can be more likely to see
a trap if that path ever gets followed.
And it makes the warning go away :-)
OK?
Andrew
PS as a side note, it would be handy to have the def point *and* the
use point that might be undefined. Its a big function and it took me
a while just to see where a possible use might be.
Bootstraps onx86_64-pc-linux-gnu with no regressions. Pushed.
Andrew
>From 387c665392366a543fb29badaee329533b32abb3 Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacl...@redhat.com>
Date: Thu, 21 Oct 2021 14:48:20 -0400
Subject: [PATCH 3/3] Initialize variable.
gcc/fortran/
* trans-decl.c (gfc_conv_cfi_to_gfc): Initialize rank to NULL_TREE.
---
gcc/fortran/trans-decl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/fortran/trans-decl.c b/gcc/fortran/trans-decl.c
index de624c82fcf..fe5511b5285 100644
--- a/gcc/fortran/trans-decl.c
+++ b/gcc/fortran/trans-decl.c
@@ -6668,7 +6668,7 @@ gfc_conv_cfi_to_gfc (stmtblock_t *init, stmtblock_t *finally,
stmtblock_t block;
gfc_init_block (&block);
tree cfi = build_fold_indirect_ref_loc (input_location, cfi_desc);
- tree rank, idx, etype, tmp, tmp2, size_var = NULL_TREE;
+ tree idx, etype, tmp, tmp2, size_var = NULL_TREE, rank = NULL_TREE;
bool do_copy_inout = false;
/* When allocatable + intent out, free the cfi descriptor. */
--
2.17.2
