diff options
| author | Richard Kenner <kenner@gcc.gnu.org> | 1994-07-30 12:58:42 -0400 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1994-07-30 12:58:42 -0400 |
| commit | 67a3773731b8a4f7a6f4f69e67d4b7ef69296136 (patch) | |
| tree | 88c52a751c27dd41d2a6c69b4ce11096be18ff91 /gcc/cse.c | |
| parent | 96c9d70dda35cd5901c6905172c44e472d49dc21 (diff) | |
| download | gcc-67a3773731b8a4f7a6f4f69e67d4b7ef69296136.tar.gz | |
(fold_rtx, case MEM): Surround TRUNCATE for jump table entry with a CONST.
(fold_rtx, case '1'): Handle operand 0 of a CONST.
(fold_rtx, case PLUS): Handle (const (minus (label_ref) (label_ref))).
From-SVN: r7832
Diffstat (limited to 'gcc/cse.c')
| -rw-r--r-- | gcc/cse.c | 40 |
1 files changed, 32 insertions, 8 deletions
diff --git a/gcc/cse.c b/gcc/cse.c index b4947d04c50..adc99329407 100644 --- a/gcc/cse.c +++ b/gcc/cse.c @@ -5001,7 +5001,11 @@ fold_rtx (x, insn) if (GET_MODE (table) != Pmode) new = gen_rtx (TRUNCATE, GET_MODE (table), new); - return new; + /* Indicate this is a constant. This isn't a + valid form of CONST, but it will only be used + to fold the next insns and then discarded, so + it should be safe. */ + return gen_rtx (CONST, GET_MODE (new), new); } } } @@ -5174,13 +5178,26 @@ fold_rtx (x, insn) switch (GET_RTX_CLASS (code)) { case '1': - /* We can't simplify extension ops unless we know the original mode. */ - if ((code == ZERO_EXTEND || code == SIGN_EXTEND) - && mode_arg0 == VOIDmode) - break; - new = simplify_unary_operation (code, mode, - const_arg0 ? const_arg0 : folded_arg0, - mode_arg0); + { + int is_const = 0; + + /* We can't simplify extension ops unless we know the + original mode. */ + if ((code == ZERO_EXTEND || code == SIGN_EXTEND) + && mode_arg0 == VOIDmode) + break; + + /* If we had a CONST, strip it off and put it back later if we + fold. */ + if (const_arg0 != 0 && GET_CODE (const_arg0) == CONST) + is_const = 1, const_arg0 = XEXP (const_arg0, 0); + + new = simplify_unary_operation (code, mode, + const_arg0 ? const_arg0 : folded_arg0, + mode_arg0); + if (new != 0 && is_const) + new = gen_rtx (CONST, mode, new); + } break; case '<': @@ -5358,6 +5375,13 @@ fold_rtx (x, insn) if (y != 0 && GET_CODE (XEXP (y, 1)) == LABEL_REF && XEXP (XEXP (y, 1), 0) == XEXP (const_arg1, 0)) return XEXP (y, 0); + + /* Now try for a CONST of a MINUS like the above. */ + if ((y = lookup_as_function (folded_arg0, CONST)) != 0 + && GET_CODE (XEXP (y, 0)) == MINUS + && GET_CODE (XEXP (XEXP (y, 0), 1)) == LABEL_REF + && XEXP (XEXP (XEXP (y, 0),1), 0) == XEXP (const_arg1, 0)) + return XEXP (XEXP (y, 0), 0); } /* If second operand is a register equivalent to a negative |