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.
