This makes sure we cleanup at least some of the spurious copies
that can be introduced for example by jump-threading and that confuse
uninitialized var analysis.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
2013-08-29 Richard Biener <rguent...@suse.de>
PR middle-end/57287
* tree-ssa-copy.c (may_propagate_copy): Allow propagating
of default defs that appear in abnormal PHI nodes.
* gcc.dg/pr57287-2.c: New testcase.
Index: gcc/tree-ssa-copy.c
===================================================================
*** gcc/tree-ssa-copy.c (revision 202068)
--- gcc/tree-ssa-copy.c (working copy)
*************** may_propagate_copy (tree dest, tree orig
*** 60,66 ****
/* If ORIG flows in from an abnormal edge, it cannot be propagated. */
if (TREE_CODE (orig) == SSA_NAME
! && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig))
return false;
/* If DEST is an SSA_NAME that flows from an abnormal edge, then it
--- 60,72 ----
/* If ORIG flows in from an abnormal edge, it cannot be propagated. */
if (TREE_CODE (orig) == SSA_NAME
! && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig)
! /* If it is the default definition and an automatic variable then
! we can though and it is important that we do to avoid
! uninitialized regular copies. */
! && !(SSA_NAME_IS_DEFAULT_DEF (orig)
! && (SSA_NAME_VAR (orig) == NULL_TREE
! || TREE_CODE (SSA_NAME_VAR (orig)) == VAR_DECL)))
return false;
/* If DEST is an SSA_NAME that flows from an abnormal edge, then it
Index: gcc/testsuite/gcc.dg/pr57287-2.c
===================================================================
*** gcc/testsuite/gcc.dg/pr57287-2.c (revision 0)
--- gcc/testsuite/gcc.dg/pr57287-2.c (working copy)
***************
*** 0 ****
--- 1,35 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O2 -Wall" } */
+
+ #include <setjmp.h>
+
+ struct node
+ {
+ struct node *next;
+ char *name;
+ } *list;
+
+ struct node *list;
+ struct node *head (void);
+
+ sigjmp_buf *bar (void);
+
+ int baz (void)
+ {
+ struct node *n;
+ int varseen = 0;
+
+ list = head ();
+ for (n = list; n; n = n->next)
+ {
+ if (!varseen)
+ varseen = 1;
+
+ sigjmp_buf *buf = bar (); /* { dg-bogus "may be used uninitialized" ""
} */
+ __sigsetjmp (*buf, 1);
+ }
+
+ if (!varseen)
+ return 0;
+ return 1;
+ }
