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re PR tree-optimization/60899 (undef reference generated with -fdevirtualize-speculatively)

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PR tree-optimization/60899
	* gimple-fold.c (can_refer_decl_in_current_unit_p): Cleanup;
	assume all static symbols will have definition wile parsing and
	check the do have definition later in compilation; check that
	variable referring symbol will be output before concluding that
	reference is safe; be conservative for referring local statics;
	be more precise about when comdat is output in other partition.

	g++.dg/ipa/devirt-11.C: Update template.

From-SVN: r210676
This commit is contained in:
Jan Hubicka 2014-05-21 08:16:03 +02:00 committed by Jan Hubicka
parent 1bbb87c4b2
commit 3aaf05290a
4 changed files with 39 additions and 37 deletions
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10
gcc/ChangeLog
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@ -1,3 +1,13 @@
2014-05-20 Jan Hubicka <hubicka@ucw.cz>
PR tree-optimization/60899
* gimple-fold.c (can_refer_decl_in_current_unit_p): Cleanup;
assume all static symbols will have definition wile parsing and
check the do have definition later in compilation; check that
variable referring symbol will be output before concluding that
reference is safe; be conservative for referring local statics;
be more precise about when comdat is output in other partition.
2014-05-20 Jan Hubicka <hubicka@ucw.cz>
PR bootstrap/60984

54
gcc/gimple-fold.c
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@ -94,8 +94,12 @@ can_refer_decl_in_current_unit_p (tree decl, tree from_decl)
/* Static objects can be referred only if they was not optimized out yet. */
if (!TREE_PUBLIC (decl) && !DECL_EXTERNAL (decl))
{
/* Before we start optimizing unreachable code we can be sure all
static objects are defined. */
if (cgraph_function_flags_ready)
return true;
snode = symtab_get_node (decl);
if (!snode)
if (!snode || !snode->definition)
return false;
node = dyn_cast <cgraph_node *> (snode);
return !node || !node->global.inlined_to;
@ -103,10 +107,12 @@ can_refer_decl_in_current_unit_p (tree decl, tree from_decl)
/* We will later output the initializer, so we can refer to it.
So we are concerned only when DECL comes from initializer of
external var. */
external var or var that has been optimized out. */
if (!from_decl
|| TREE_CODE (from_decl) != VAR_DECL
|| !DECL_EXTERNAL (from_decl)
|| (!DECL_EXTERNAL (from_decl)
&& (vnode = varpool_get_node (from_decl)) != NULL
&& vnode->definition)
|| (flag_ltrans
&& symtab_get_node (from_decl)->in_other_partition))
return true;
@ -123,9 +129,9 @@ can_refer_decl_in_current_unit_p (tree decl, tree from_decl)
reference imply need to include function body in the curren tunit. */
if (TREE_PUBLIC (decl) && !DECL_COMDAT (decl))
return true;
/* We are not at ltrans stage; so don't worry about WHOPR.
Also when still gimplifying all referred comdat functions will be
produced.
/* We have COMDAT. We are going to check if we still have definition
or if the definition is going to be output in other partition.
Bypass this when gimplifying; all needed functions will be produced.
As observed in PR20991 for already optimized out comdat virtual functions
it may be tempting to not necessarily give up because the copy will be
@ -134,35 +140,17 @@ can_refer_decl_in_current_unit_p (tree decl, tree from_decl)
units where they are used and when the other unit was compiled with LTO
it is possible that vtable was kept public while the function itself
was privatized. */
if (!flag_ltrans && (!DECL_COMDAT (decl) || !cgraph_function_flags_ready))
if (!cgraph_function_flags_ready)
return true;
/* OK we are seeing either COMDAT or static variable. In this case we must
check that the definition is still around so we can refer it. */
if (TREE_CODE (decl) == FUNCTION_DECL)
{
node = cgraph_get_node (decl);
/* Check that we still have function body and that we didn't took
the decision to eliminate offline copy of the function yet.
The second is important when devirtualization happens during final
compilation stage when making a new reference no longer makes callee
to be compiled. */
if (!node || !node->definition || node->global.inlined_to)
{
gcc_checking_assert (!TREE_ASM_WRITTEN (decl));
return false;
}
}
else if (TREE_CODE (decl) == VAR_DECL)
{
vnode = varpool_get_node (decl);
if (!vnode || !vnode->definition)
{
gcc_checking_assert (!TREE_ASM_WRITTEN (decl));
return false;
}
}
return true;
snode = symtab_get_node (decl);
if (!snode
|| ((!snode->definition || DECL_EXTERNAL (decl))
&& (!snode->in_other_partition
|| (!snode->forced_by_abi && !snode->force_output))))
return false;
node = dyn_cast <cgraph_node *> (snode);
return !node || !node->global.inlined_to;
}
/* CVAL is value taken from DECL_INITIAL of variable. Try to transform it into

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2014-05-20 Jan Hubicka <hubicka@ucw.cz>
PR tree-optimization/60899
g++.dg/ipa/devirt-11.C: Update template.
2014-05-20 Edward Smith-Rowland <3dw4rd@verizon.net>
PR C++/61038

7
gcc/testsuite/g++.dg/ipa/devirt-11.C
View File

@ -42,8 +42,7 @@ bar ()
baz ();
c + d;
}
/* While inlining function called once we should devirtualize a new call to fn2
and two to fn3. While doing so the new symbol for fn2 needs to be
introduced. */
/* { dg-final { scan-ipa-dump-times "Discovered a virtual call to a known target" 3 "inline" } } */
/* While inlining function called once we should devirtualize a new call to fn3.
Because fn2 is already removed, we should not devirtualize. */
/* { dg-final { scan-ipa-dump-times "Discovered a virtual call to a known target" 1 "inline" } } */
/* { dg-final { cleanup-ipa-dump "inline" } } */