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| author | Richard Kenner <kenner@gcc.gnu.org> | 1992-12-27 06:52:16 -0500 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1992-12-27 06:52:16 -0500 |
| commit | 818b11b942756b6af4e2dd01e2893e224076d40c (patch) | |
| tree | 427a97eebe48afa2f8c4e8369bce19e50ff1b38a /gcc/combine.c | |
| parent | 3b94d087e81d9b39a0944a325825d49b557f3423 (diff) | |
| download | gcc-818b11b942756b6af4e2dd01e2893e224076d40c.zip gcc-818b11b942756b6af4e2dd01e2893e224076d40c.tar.gz gcc-818b11b942756b6af4e2dd01e2893e224076d40c.tar.bz2 | |
(subst, comparison cases): Expand any compound operation that is an operand...
(subst, comparison cases): Expand any compound operation that is an
operand; rerun subst on simplified result in one new case.
From-SVN: r2922
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 360c81e..db80ef2 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -3370,17 +3370,27 @@ subst (x, from, to, in_dest, unique_copy) /* If STORE_FLAG_VALUE is 1, we can convert (ne x 0) to simply X if only the low-order bit is significant in X (such as when X is a ZERO_EXTRACT of one bit. Similarly, we can convert - EQ to (xor X 1). */ + EQ to (xor X 1). Remove any ZERO_EXTRACT we made when thinking + this was a comparison. It may now be simpler to use, e.g., an + AND. If a ZERO_EXTRACT is indeed appropriate, it will + be placed back by the call to make_compound_operation in the + SET case. */ if (new_code == NE && GET_MODE_CLASS (mode) == MODE_INT && op1 == const0_rtx && significant_bits (op0, GET_MODE (op0)) == 1) - return gen_lowpart_for_combine (mode, op0); + return gen_lowpart_for_combine (mode, + expand_compound_operation (op0)); else if (new_code == EQ && GET_MODE_CLASS (mode) == MODE_INT && op1 == const0_rtx && significant_bits (op0, GET_MODE (op0)) == 1) - return gen_rtx_combine (XOR, mode, - gen_lowpart_for_combine (mode, op0), - const1_rtx); + { + op0 = expand_compound_operation (op0); + + x = gen_rtx_combine (XOR, mode, + gen_lowpart_for_combine (mode, op0), + const1_rtx); + goto restart; + } #endif #if STORE_FLAG_VALUE == -1 @@ -3392,6 +3402,7 @@ subst (x, from, to, in_dest, unique_copy) && op1 == const0_rtx && significant_bits (op0, GET_MODE (op0)) == 1) { + op0 = expand_compound_operation (op0); x = gen_rtx_combine (NEG, mode, gen_lowpart_for_combine (mode, op0)); goto restart; @@ -3411,7 +3422,8 @@ subst (x, from, to, in_dest, unique_copy) && mode == GET_MODE (op0) && (i = exact_log2 (significant_bits (op0, GET_MODE (op0)))) >= 0) { - x = simplify_shift_const (NULL_RTX, ASHIFT, mode, op0, + x = simplify_shift_const (NULL_RTX, ASHIFT, mode, + expand_compound_operation (op0), GET_MODE_BITSIZE (mode) - 1 - i); if (GET_CODE (x) == AND && XEXP (x, 1) == const_true_rtx) return XEXP (x, 0); |