re PR rtl-optimization/56178 (Miscompilation of Ada front-end with profiled bootstrap)

	PR rtl-optimization/56178
	* cse.c (cse_insn): Do not create a REG_EQUAL note if the source is a
	SUBREG of a register.  Tidy up related block of code.
	* fwprop.c (forward_propagate_and_simplify): Do not create a REG_EQUAL
	note if the source is a register or a SUBREG of a register.

From-SVN: r195841

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 175b85bb2648d7a81d9cfd2cc5986cd81389b32b..b7914b5dfe1807416855c57763590beae5e56de3 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2013-02-07  Eric Botcazou  <ebotcazou@adacore.com>
+
+       PR rtl-optimization/56178
+       * cse.c (cse_insn): Do not create a REG_EQUAL note if the source is a
+       SUBREG of a register.  Tidy up related block of code.
+       * fwprop.c (forward_propagate_and_simplify): Do not create a REG_EQUAL
+       note if the source is a register or a SUBREG of a register.
+
 2013-02-07  Jakub Jelinek  <jakub@redhat.com>
 
        PR target/56228

diff --git a/gcc/cse.c b/gcc/cse.c
index 32bed42befeb954a3a02622211a0d1eef3650849..b200fef4dfbac1dc9fd0ec0a2f46c736b3f85052 100644 (file)
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -5311,33 +5311,33 @@ cse_insn (rtx insn)
        }
 
       /* If this is a single SET, we are setting a register, and we have an
-        equivalent constant, we want to add a REG_NOTE.   We don't want
-        to write a REG_EQUAL note for a constant pseudo since verifying that
-        that pseudo hasn't been eliminated is a pain.  Such a note also
-        won't help anything.
+        equivalent constant, we want to add a REG_EQUAL note if the constant
+        is different from the source.  We don't want to do it for a constant
+        pseudo since verifying that this pseudo hasn't been eliminated is a
+        pain; moreover such a note won't help anything.
 
         Avoid a REG_EQUAL note for (CONST (MINUS (LABEL_REF) (LABEL_REF)))
         which can be created for a reference to a compile time computable
         entry in a jump table.  */
-
-      if (n_sets == 1 && src_const && REG_P (dest)
+      if (n_sets == 1
+         && REG_P (dest)
+         && src_const
          && !REG_P (src_const)
-         && ! (GET_CODE (src_const) == CONST
-               && GET_CODE (XEXP (src_const, 0)) == MINUS
-               && GET_CODE (XEXP (XEXP (src_const, 0), 0)) == LABEL_REF
-               && GET_CODE (XEXP (XEXP (src_const, 0), 1)) == LABEL_REF))
+         && !(GET_CODE (src_const) == SUBREG
+              && REG_P (SUBREG_REG (src_const)))
+         && !(GET_CODE (src_const) == CONST
+              && GET_CODE (XEXP (src_const, 0)) == MINUS
+              && GET_CODE (XEXP (XEXP (src_const, 0), 0)) == LABEL_REF
+              && GET_CODE (XEXP (XEXP (src_const, 0), 1)) == LABEL_REF)
+         && !rtx_equal_p (src, src_const))
        {
-         /* We only want a REG_EQUAL note if src_const != src.  */
-         if (! rtx_equal_p (src, src_const))
-           {
-             /* Make sure that the rtx is not shared.  */
-             src_const = copy_rtx (src_const);
+         /* Make sure that the rtx is not shared.  */
+         src_const = copy_rtx (src_const);
 
-             /* Record the actual constant value in a REG_EQUAL note,
-                making a new one if one does not already exist.  */
-             set_unique_reg_note (insn, REG_EQUAL, src_const);
-             df_notes_rescan (insn);
-           }
+         /* Record the actual constant value in a REG_EQUAL note,
+            making a new one if one does not already exist.  */
+         set_unique_reg_note (insn, REG_EQUAL, src_const);
+         df_notes_rescan (insn);
        }
 
       /* Now deal with the destination.  */

diff --git a/gcc/fwprop.c b/gcc/fwprop.c
index 6a82deabfd10a0a9a828664331117b4e4e44eb0d..17cc62aa2e4e2cfcfd1dc0135ef20722301b12dd 100644 (file)
--- a/gcc/fwprop.c
+++ b/gcc/fwprop.c
@@ -1316,10 +1316,16 @@ forward_propagate_and_simplify (df_ref use, rtx def_insn, rtx def_set)
         separately try plugging the definition in the note and simplifying.
         And only install a REQ_EQUAL note when the destination is a REG
         that isn't mentioned in USE_SET, as the note would be invalid
-        otherwise.  */
-      set_reg_equal = (note == NULL_RTX && REG_P (SET_DEST (use_set))
-                      && ! reg_mentioned_p (SET_DEST (use_set),
-                                            SET_SRC (use_set)));
+        otherwise.  We also don't want to install a note if we are merely
+        propagating a pseudo since verifying that this pseudo isn't dead
+        is a pain; moreover such a note won't help anything.  */
+      set_reg_equal = (note == NULL_RTX
+                      && REG_P (SET_DEST (use_set))
+                      && !REG_P (src)
+                      && !(GET_CODE (src) == SUBREG
+                           && REG_P (SUBREG_REG (src)))
+                      && !reg_mentioned_p (SET_DEST (use_set),
+                                           SET_SRC (use_set)));
     }
 
   if (GET_MODE (*loc) == VOIDmode)