This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty function

In message <>,
 >>Number:         10862
 >>Category:       optimization
 >>Synopsis:       [tree-ssa] Segfault for (essentially) empty function
 >>Confidential:   no
 >>Severity:       serious
 >>Priority:       medium
 >>Responsible:    unassigned
 >>State:          open
 >>Class:          sw-bug
 >>Submitter-Id:   net
 >>Arrival-Date:   Mon May 19 14:46:01 UTC 2003
 >>Originator:     Wolfgang Bangerth
 >>Release:        unknown-1.0
 >This one's rather funny (and was much simpler to reduce).
 >We ICE on a function that's essentially empty:
 >---------------------------------------template <int N> void foo () {
 >  int i;
 >  switch (i) {
 >    case 1:
 >          switch (N) {}
 >    default: ;
 >  }
 >template void foo<1> ();
 >g/x> /home/bangerth/bin/gcc-3.4-tree-ssa/bin/c++ -O2 -c
 > In function `void foo() [with int N = 1]':
 >   instantiated from here
 > internal compiler error: Segmentation fault
 >Please submit a full bug report,
 >with preprocessed source if appropriate.
 >See <URL:> for instructions.
This patch ought to fix this problem.

	* tree-ssa-dce.c (remove_conditional): If the conditional's block
	has no post dominator in the CFG, then wire it to the exit node.
	Avoid unnecessary check of bb->succ.

Index: tree-ssa-dce.c
RCS file: /cvs/gcc/gcc/gcc/Attic/tree-ssa-dce.c,v
retrieving revision
diff -c -3 -p -r1.1.2.37 tree-ssa-dce.c
*** tree-ssa-dce.c	16 May 2003 18:09:19 -0000
--- tree-ssa-dce.c	19 May 2003 16:50:25 -0000
*************** remove_conditional (basic_block bb)
*** 627,632 ****
--- 627,637 ----
    if (bb->succ)
+   /* If there is no post dominator, then this block is going to the
+      exit node.  */
+   if (pdom_bb == NULL)
+     pdom_bb = EXIT_BLOCK_PTR;
    /* If the post dominator has any PHI nodes in it at all, the 
       conditional has been marked as necessary. This means no PHI
       node updating is required. If there are any PHI nodes, its a bug
*************** remove_conditional (basic_block bb)
*** 642,647 ****
    /* Add an edge to BB's post dominator.  */
!   if (bb->succ == NULL)
!     make_edge (bb, pdom_bb,  EDGE_FALLTHRU);
--- 647,651 ----
    /* Add an edge to BB's post dominator.  */
!   make_edge (bb, pdom_bb,  EDGE_FALLTHRU);

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]