* reg-notes.def (EQUAL): Mention significance of combination of
REG_EQUAL and REG_RETVAL.
* fwprop.c (try_fwprop_subst): Don't add REG_EQUAL to an
insn that has a REG_RETVAL.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@132053
138bc75d-0d04-0410-961f-
82ee72b054a4
+2008-02-01 Hans-Peter Nilsson <hp@axis.com>
+
+ PR rtl-optimization/34773
+ * reg-notes.def (EQUAL): Mention significance of combination of
+ REG_EQUAL and REG_RETVAL.
+ * fwprop.c (try_fwprop_subst): Don't add REG_EQUAL to an
+ insn that has a REG_RETVAL.
+
2008-02-01 Roger Sayle <roger@eyesopen.com>
PR bootstrap/33781
{
cancel_changes (0);
- /* Can also record a simplified value in a REG_EQUAL note, making a
- new one if one does not already exist. */
- if (set_reg_equal)
+ /* Can also record a simplified value in a REG_EQUAL note,
+ making a new one if one does not already exist.
+ Don't do this if the insn has a REG_RETVAL note, because the
+ combined presence means that the REG_EQUAL note refers to the
+ (full) contents of the libcall value. */
+ if (set_reg_equal && !find_reg_note (insn, REG_RETVAL, NULL_RTX))
{
if (dump_file)
fprintf (dump_file, " Setting REG_EQUAL note\n");
/* Like REG_EQUIV except that the destination is only momentarily
equal to the specified rtx. Therefore, it cannot be used for
- substitution; but it can be used for cse. */
+ substitution; but it can be used for cse. Together with a
+ REG_RETVAL note, it means that the insn sets the full contents of
+ the libcall value. */
REG_NOTE (EQUAL)
/* This insn copies the return-value of a library call out of the hard