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| author | Richard Stallman <rms@gnu.org> | 1992-11-26 05:34:24 +0000 |
|---|---|---|
| committer | Richard Stallman <rms@gnu.org> | 1992-11-26 05:34:24 +0000 |
| commit | 3e3ea975fcafcb1280bd480f06058066d2a26b5f (patch) | |
| tree | ada8ded647fd38b2aa0ac4a0a5e782c0f33a927c /gcc/combine.c | |
| parent | 711f122a854e3b3845abc2a43378d4073ae41ac1 (diff) | |
| download | gcc-3e3ea975fcafcb1280bd480f06058066d2a26b5f.zip gcc-3e3ea975fcafcb1280bd480f06058066d2a26b5f.tar.gz gcc-3e3ea975fcafcb1280bd480f06058066d2a26b5f.tar.bz2 | |
(make_extraction): When making a low part subreg of a reg,
use inner_mode, not is_mode.
(num_sign_bit_copies): Inhibit x-1 special case
when x is a paradoxical subreg.
From-SVN: r2802
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 76fbe1b..1021391 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -4632,8 +4632,8 @@ make_extraction (mode, inner, pos, pos_rtx, len, a SUBREG and it would sometimes return a new hard register. */ new = gen_rtx (SUBREG, tmode, inner, (WORDS_BIG_ENDIAN - && GET_MODE_SIZE (is_mode) > UNITS_PER_WORD - ? ((GET_MODE_SIZE (is_mode) - GET_MODE_SIZE (tmode)) + && GET_MODE_SIZE (inner_mode) > UNITS_PER_WORD + ? ((GET_MODE_SIZE (inner_mode) - GET_MODE_SIZE (tmode)) / UNITS_PER_WORD) : 0)); else @@ -6345,7 +6345,12 @@ num_sign_bit_copies (x, mode) be such a carry. Furthermore, if the positive number is known to be 0 or 1, we know the result is either -1 or 0. */ - if (code == PLUS && XEXP (x, 1) == constm1_rtx) + if (code == PLUS && XEXP (x, 1) == constm1_rtx + /* Don't do this if XEXP (x, 0) is a paradoxical subreg + because in principle we don't know what the high bits are. */ + && !(GET_CODE (XEXP (x, 0)) == SUBREG + && (GET_MODE_SIZE (GET_MODE (XEXP (XEXP (x, 0), 0))) + < GET_MODE_SIZE (GET_MODE (XEXP (x, 0)))))) { sig = significant_bits (XEXP (x, 0), mode); if ((((HOST_WIDE_INT) 1 << (bitwidth - 1)) & sig) == 0) |