diff options
author | Uros Bizjak <ubizjak@gmail.com> | 2012-04-02 10:04:10 +0000 |
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committer | Uros Bizjak <ubizjak@gmail.com> | 2012-04-02 10:04:10 +0000 |
commit | e29d0c53caff9174a68bf6aac09153e1b16f8c79 (patch) | |
tree | 25a87d90e52dfd9812287295b22efbecb3a3a3a1 /gcc/combine.c | |
parent | efe23f1adada05509106d9fe65e2e79c98f38e04 (diff) |
Partially revert:
2012-03-29 Richard Guenther <rguenther@suse.de>
* rtl.h (extended_count): Remove.
* combine.c (extended_count): Remove.
git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@186077 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/combine.c')
-rw-r--r-- | gcc/combine.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index de3afccb446..7eaaf476c6e 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -9674,6 +9674,31 @@ reg_num_sign_bit_copies_for_combine (const_rtx x, enum machine_mode mode, return NULL; } +/* Return the number of "extended" bits there are in X, when interpreted + as a quantity in MODE whose signedness is indicated by UNSIGNEDP. For + unsigned quantities, this is the number of high-order zero bits. + For signed quantities, this is the number of copies of the sign bit + minus 1. In both case, this function returns the number of "spare" + bits. For example, if two quantities for which this function returns + at least 1 are added, the addition is known not to overflow. + + This function will always return 0 unless called during combine, which + implies that it must be called from a define_split. */ + +unsigned int +extended_count (const_rtx x, enum machine_mode mode, int unsignedp) +{ + if (nonzero_sign_valid == 0) + return 0; + + return (unsignedp + ? (HWI_COMPUTABLE_MODE_P (mode) + ? (unsigned int) (GET_MODE_PRECISION (mode) - 1 + - floor_log2 (nonzero_bits (x, mode))) + : 0) + : num_sign_bit_copies (x, mode) - 1); +} + /* This function is called from `simplify_shift_const' to merge two outer operations. Specifically, we have already found that we need to perform operation *POP0 with constant *PCONST0 at the outermost |