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* [Bug tree-optimization/65355] New: [4.8/4.9 Regression] vectorizer increase alignment of symbols already placed in anchors
@ 2015-03-08 23:34 hubicka at gcc dot gnu.org
  2015-03-09 14:43 ` [Bug tree-optimization/65355] [4.8/4.9/5 " rguenth at gcc dot gnu.org
                   ` (7 more replies)
  0 siblings, 8 replies; 9+ messages in thread
From: hubicka at gcc dot gnu.org @ 2015-03-08 23:34 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65355

            Bug ID: 65355
           Summary: [4.8/4.9 Regression] vectorizer increase alignment of
                    symbols already placed in anchors
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hubicka at gcc dot gnu.org

Increasing alignment of symbol does not work once RTL containing anchor was
produced.

Index: symtab.c
===================================================================
--- symtab.c  (revision 221268)
+++ symtab.c  (working copy)
@@ -1924,6 +1924,13 @@ symtab_node::can_increase_alignment_p (v
   if (TREE_ASM_WRITTEN (target->decl))
     return false;

+  /* If target is already placed in an anchor, we can not touch its
+     alignment.  */
+  if (DECL_RTL_SET_P (target->decl)
+      && MEM_P (DECL_RTL (target->decl))
+      && SYMBOL_REF_HAS_BLOCK_INFO_P (XEXP (DECL_RTL (target->decl), 0)))
+    return false;
+
   /* Constant pool entries may be shared.  */
   if (DECL_IN_CONSTANT_POOL (target->decl))
     return false;

sadly introduce quite few testsuite regressions for ppc-linux (checking that
alignmnet was increased). This is because notice_global_symbol produces RTL
early and thus blocks this.

I suppose notice_global_symbol needs to be redone to work on tree only. For
next stage1 we also probably want to drop the increase_alignmnets IPA pass and
run all late tree passes prior RTL generation.


^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2015-06-26 20:27 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-03-08 23:34 [Bug tree-optimization/65355] New: [4.8/4.9 Regression] vectorizer increase alignment of symbols already placed in anchors hubicka at gcc dot gnu.org
2015-03-09 14:43 ` [Bug tree-optimization/65355] [4.8/4.9/5 " rguenth at gcc dot gnu.org
2015-03-10  4:24 ` hubicka at gcc dot gnu.org
2015-03-11  9:19 ` [Bug tree-optimization/65355] [4.8/4.9 " jakub at gcc dot gnu.org
2015-03-11 20:31 ` pthaugen at gcc dot gnu.org
2015-03-13  1:09 ` hubicka at gcc dot gnu.org
2015-06-23  8:19 ` rguenth at gcc dot gnu.org
2015-06-26 19:54 ` [Bug tree-optimization/65355] [4.9 " jakub at gcc dot gnu.org
2015-06-26 20:27 ` jakub at gcc dot gnu.org

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