diff options
Diffstat (limited to 'gcc/fwprop.c')
| -rw-r--r-- | gcc/fwprop.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/gcc/fwprop.c b/gcc/fwprop.c index 6a82dea..17cc62a 100644 --- 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) |