diff options
| author | law <law@138bc75d-0d04-0410-961f-82ee72b054a4> | 1998-10-05 09:05:58 +0000 |
|---|---|---|
| committer | law <law@138bc75d-0d04-0410-961f-82ee72b054a4> | 1998-10-05 09:05:58 +0000 |
| commit | fc84b6f26828d89c4c34d17d5cc6a813aca0a972 (patch) | |
| tree | 9ece943458af2f7b8f7e40902dc98b737f1316d0 /gcc/combine.c | |
| parent | 12914686d56ac93a91d67c3c23f8e96e853777a2 (diff) | |
| download | gcc-fc84b6f26828d89c4c34d17d5cc6a813aca0a972.tar.gz | |
8
* combine.c (simplify_rtx): Do not replace TRUNCATE with a SUBREG if
truncation is not a no-op.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@22835 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index ce488e294c4..420a60fca5f 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -3773,9 +3773,12 @@ simplify_rtx (x, op0_mode, last, in_dest) return SUBREG_REG (XEXP (x, 0)); /* If we know that the value is already truncated, we can - replace the TRUNCATE with a SUBREG. */ - if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (XEXP (x, 0))) - >= GET_MODE_BITSIZE (mode) + 1) + replace the TRUNCATE with a SUBREG if TRULY_NOOP_TRUNCATION is + nonzero for the corresponding modes. */ + if (TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode), + GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))) + && num_sign_bit_copies (XEXP (x, 0), GET_MODE (XEXP (x, 0))) + >= GET_MODE_BITSIZE (mode) + 1) return gen_lowpart_for_combine (mode, XEXP (x, 0)); /* A truncate of a comparison can be replaced with a subreg if |