re PR rtl-optimization/46315 (-O2 -fno-strict-overflow causes wrong code generation)

	PR rtl-optimization/46315
	* rtl.h (remove_reg_equal_equiv_notes_for_regno): Declare.
	* rtlanal.c (remove_reg_equal_equiv_notes_for_regno): New function
	extracted from...
	* dce.c (delete_corresponding_reg_eq_notes): ...here.  Rename into...
	(remove_reg_equal_equiv_notes_for_defs): ...this.
	(delete_unmarked_insns): Adjust to above renaming.
	* ifcvt.c (dead_or_predicable): Remove REG_EQUAL and REG_EQUIV notes
	referring to registers set in the insns being moved, if any.

	* df-core.c (df_ref_dump): New function extracted from...
	(df_refs_chain_dump): ...here.  Call it.
	(df_regs_chain_dump): Likewise.
	* df-problems.c (df_chain_dump): Print 'e' for uses in notes.
	* df-scan.c (df_scan_start_dump): Likewise.  Fix long line.

From-SVN: r166827

1 files changed, 27 insertions, 0 deletions

diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index 930828a..eb4d3ab 100644
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -1941,6 +1941,33 @@ remove_reg_equal_equiv_notes (rtx insn)
     }
 }
 
+/* Remove all REG_EQUAL and REG_EQUIV notes referring to REGNO.  */
+
+void
+remove_reg_equal_equiv_notes_for_regno (unsigned int regno)
+{
+  df_ref eq_use;
+
+  if (!df)
+    return;
+
+  /* This loop is a little tricky.  We cannot just go down the chain because
+     it is being modified by some actions in the loop.  So we just iterate
+     over the head.  We plan to drain the list anyway.  */
+  while ((eq_use = DF_REG_EQ_USE_CHAIN (regno)) != NULL)
+    {
+      rtx insn = DF_REF_INSN (eq_use);
+      rtx note = find_reg_equal_equiv_note (insn);
+
+      /* This assert is generally triggered when someone deletes a REG_EQUAL
+	 or REG_EQUIV note by hacking the list manually rather than calling
+	 remove_note.  */
+      gcc_assert (note);
+
+      remove_note (insn, note);
+    }
+}
+
 /* Search LISTP (an EXPR_LIST) for an entry whose first operand is NODE and
    return 1 if it is found.  A simple equality test is used to determine if
    NODE matches.  */