On Sun, Jul 08, 2018 at 11:22:41AM +0200, Tom de Vries wrote:
> On Fri, Jul 06, 2018 at 04:38:50PM +0200, Richard Biener wrote:
> > On Fri, Jul 6, 2018 at 12:47 PM Tom de Vries <tdevr...@suse.de> wrote:
> > > On 07/05/2018 01:39 PM, Richard Biener wrote:
>
> <SNIP>
>
> > I now also spotted the code in remap_ssa_name that is supposed to handle
> > this it seems and for the testcase we only give up because the PARM_DECL is
> > remapped to a VAR_DECL. So I suppose it is to be handled via the
> > debug-args stuff
> > which probably lacks in the area of versioning.
> >
> > Your patch feels like it adds stuff ontop of existing mechanisms that
> > should "just work"
> > with the correct setup at the correct places...
> >
>
> Hmm, I realized that I may be complicating things, by trying to do an
> optimal fix in a single patch, so I decided to write two patches, one
> with a fix, and then one improving the fix to be more optimal.
>
> Also, I suspect that the "just work" approach is this:
> ...
> # DEBUG D#8 s=> iD.1900
> # DEBUG iD.1949 => D#8
> # DEBUG D#6 s=> iD.1949
> ...
> whereas previously I tried to map 'D#6' on iD.1900 directly.
>
Second patch OK for trunk?
Thanks,
- Tom
[debug] Reuse debug exprs generated in remap_ssa_name
When compiling gcc.dg/vla-1.c with -O3 -g, vla a and b in f1 are optimized
away, and f1 is cloned to a version f1.constprop with no parameters, eliminating
parameter i. Debug info is generated to describe the sizes of a and b, but
that process generates debug expressions that are not reused.
Fix the duplication by saving and reusing the generated debug expressions in
remap_ssa_name. Concretely: reuse D#7 here instead of generating D#8:
...
__attribute__((noinline))
f1.constprop ()
{
intD.6 iD.1935;
<bb 3>
# DEBUG D#10 s=> iD.1897
# DEBUG iD.1935 => D#10
<bb 2>
- # DEBUG D#8 s=> iD.1935
# DEBUG D#7 s=> iD.1935
saved_stack.2_1 = __builtin_stack_save ();
# DEBUG BEGIN_STMT
# DEBUG D#6 => D#7 + 1
# DEBUG D#5 => (long intD.8) D#6
# DEBUG D#4 => D#5 + -1
# DEBUG D.1937 => (sizetype) D#4
# DEBUG a.0D.1942 => NULL
# DEBUG BEGIN_STMT
- # DEBUG D#3 => D#8 + 2
+ # DEBUG D#3 => D#7 + 2
# DEBUG D#2 => (long intD.8) D#3
# DEBUG D#1 => D#2 + -1
# DEBUG D.1944 => (sizetype) D#1
# DEBUG b.1D.1949 => NULL
...
Bootstrapped and reg-tested on x86_64.
2018-07-07 Tom de Vries <tdevr...@suse.de>
* tree-inline.c (remap_ssa_name): Save and reuse debug exprs generated
in remap_ssa_name.
* gcc.dg/vla-1.c: Update.
---
gcc/testsuite/gcc.dg/vla-1.c | 5 +++--
gcc/tree-inline.c | 4 ++++
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/vla-1.c b/gcc/testsuite/gcc.dg/vla-1.c
index 0c19feffd2b..94db23d1336 100644
--- a/gcc/testsuite/gcc.dg/vla-1.c
+++ b/gcc/testsuite/gcc.dg/vla-1.c
@@ -20,6 +20,7 @@ main ()
return 0;
}
-/* One debug source bind is generated for the parameter, and two to describe
the
+/* One debug source bind is generated for the parameter, and one to describe
the
sizes of a and b. */
-/* { dg-final { scan-tree-dump-times " s=> i" 3 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " s=> i" 2 "optimized" } } */
+
diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
index 6fbd8c3ca61..164c7fff710 100644
--- a/gcc/tree-inline.c
+++ b/gcc/tree-inline.c
@@ -215,12 +215,16 @@ remap_ssa_name (tree name, copy_body_data *id)
processing_debug_stmt = -1;
return name;
}
+ n = id->decl_map->get (val);
+ if (n && TREE_CODE (*n) == DEBUG_EXPR_DECL)
+ return *n;
def_temp = gimple_build_debug_source_bind (vexpr, val, NULL);
DECL_ARTIFICIAL (vexpr) = 1;
TREE_TYPE (vexpr) = TREE_TYPE (name);
SET_DECL_MODE (vexpr, DECL_MODE (SSA_NAME_VAR (name)));
gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT);
+ insert_decl_map (id, val, vexpr);
return vexpr;
}
