OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

re PR c++/89698 (Run-time error due to optimization of field access after cast at -Os/-O2 and higher)

Browse Source 
2019-05-03  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/89698
	* gimple-fold.c (canonicalize_constructor_val): Early out
	for constants, handle unfolded INTEGER_CSTs as they appear in
	C++ virtual table ctors.

	* g++.dg/tree-ssa/pr89698.C: New testcase.

From-SVN: r270833
This commit is contained in:
Richard Biener 2019-05-03 07:07:28 +00:00 committed by Richard Biener
parent c0f9d1fd7e
commit 37f808c4a6
4 changed files with 53 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
gcc/ChangeLog
View File

@ -1,3 +1,10 @@
2019-05-03 Richard Biener <rguenther@suse.de>
PR tree-optimization/89698
* gimple-fold.c (canonicalize_constructor_val): Early out
for constants, handle unfolded INTEGER_CSTs as they appear in
C++ virtual table ctors.
2019-05-03 Richard Biener <rguenther@suse.de>
* passes.c (execute_function_todo): Remove dead code.

14
gcc/gimple-fold.c
View File

@ -207,6 +207,9 @@ create_tmp_reg_or_ssa_name (tree type, gimple *stmt)
tree
canonicalize_constructor_val (tree cval, tree from_decl)
{
if (CONSTANT_CLASS_P (cval))
return cval;
tree orig_cval = cval;
STRIP_NOPS (cval);
if (TREE_CODE (cval) == POINTER_PLUS_EXPR
@ -257,8 +260,15 @@ canonicalize_constructor_val (tree cval, tree from_decl)
cval = fold_convert (TREE_TYPE (orig_cval), cval);
return cval;
}
if (TREE_OVERFLOW_P (cval))
return drop_tree_overflow (cval);
/* In CONSTRUCTORs we may see unfolded constants like (int (*) ()) 0. */
if (TREE_CODE (cval) == INTEGER_CST)
{
if (TREE_OVERFLOW_P (cval))
cval = drop_tree_overflow (cval);
if (!useless_type_conversion_p (TREE_TYPE (orig_cval), TREE_TYPE (cval)))
cval = fold_convert (TREE_TYPE (orig_cval), cval);
return cval;
}
return orig_cval;
}

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2019-05-03 Richard Biener <rguenther@suse.de>
PR tree-optimization/89698
* g++.dg/tree-ssa/pr89698.C: New testcase.
2019-05-02 Iain Sandoe <iain@sandoe.co.uk>
* g++.dg/ext/instantiate2.C: Remove special-casing for Darwin.

29
gcc/testsuite/g++.dg/tree-ssa/pr89698.C Normal file
View File

@ -0,0 +1,29 @@
// { dg-do compile }
// { dg-options "-O -fdump-tree-fre1" }
class A {
virtual void f(){};
public:
int x;
A(int in): x(in) {};
};
class B: public A {
public:
int y;
B(int in):A(in-1), y(in) {};
};
void bar(void *);
void test()
{
B b(2);
A* bp = &b;
void* vp = dynamic_cast<void*>(bp);
bar (vp);
}
// We should be able to constant fold from the virtual table
// the offset added to bp for the dynamic cast and forward
// &b to the argument of bar
// { dg-final { scan-tree-dump "bar \\\(&b" "fre1" } }