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| author | Richard Henderson <rth@cygnus.com> | 2000-08-16 00:56:04 -0700 |
|---|---|---|
| committer | Richard Henderson <rth@gcc.gnu.org> | 2000-08-16 00:56:04 -0700 |
| commit | 853d88280aa4989f22b716b55f80b0d36ae5fc27 (patch) | |
| tree | 063dee2e529b7990805b0203f057fade59de7b59 /gcc/combine.c | |
| parent | cbd273a8034166dc9f5c5d2db54d549103d2bf0c (diff) | |
| download | gcc-853d88280aa4989f22b716b55f80b0d36ae5fc27.zip gcc-853d88280aa4989f22b716b55f80b0d36ae5fc27.tar.gz gcc-853d88280aa4989f22b716b55f80b0d36ae5fc27.tar.bz2 | |
combine.c (simplify_shift_const): Revert previous two changes.
* combine.c (simplify_shift_const): Revert previous two
changes. If SHIFT_COUNT_TRUNCATED, crop the shift count
before the main loop.
From-SVN: r35742
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index e4be714..9e7083b 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -8851,6 +8851,14 @@ simplify_shift_const (x, code, result_mode, varop, input_count) count = input_count; + /* Make sure and truncate the "natural" shift on the way in. We don't + want to do this inside the loop as it makes it more difficult to + combine shifts. */ +#ifdef SHIFT_COUNT_TRUNCATED + if (SHIFT_COUNT_TRUNCATED) + count %= GET_MODE_BITSIZE (mode); +#endif + /* Unless one of the branches of the `if' in this loop does a `continue', we will `break' the loop after the `if'. */ @@ -8879,11 +8887,10 @@ simplify_shift_const (x, code, result_mode, varop, input_count) ? result_mode : mode); /* Handle cases where the count is greater than the size of the mode - minus 1. If SHIFT_COUNT_TRUNCATED, there aren't really any such - cases. Otherwise, for ASHIFT, use the size minus one as the count - (this can occur when simplifying (lshiftrt (ashiftrt ..))). For - rotates, take the count modulo the size. For other shifts, the - result is zero. + minus 1. For ASHIFT, use the size minus one as the count (this can + occur when simplifying (lshiftrt (ashiftrt ..))). For rotates, + take the count modulo the size. For other shifts, the result is + zero. Since these shifts are being produced by the compiler by combining multiple operations, each of which are defined, we know what the @@ -8891,11 +8898,6 @@ simplify_shift_const (x, code, result_mode, varop, input_count) if (count > GET_MODE_BITSIZE (shift_mode) - 1) { -#ifdef SHIFT_COUNT_TRUNCATED - if (SHIFT_COUNT_TRUNCATED) - count %= GET_MODE_BITSIZE (shift_mode); - else -#endif if (code == ASHIFTRT) count = GET_MODE_BITSIZE (shift_mode) - 1; else if (code == ROTATE || code == ROTATERT) @@ -9149,8 +9151,6 @@ simplify_shift_const (x, code, result_mode, varop, input_count) break; count += first_count; - if (count >= GET_MODE_BITSIZE (shift_mode)) - count = GET_MODE_BITSIZE (shift_mode) - 1; varop = XEXP (varop, 0); continue; } @@ -9204,9 +9204,6 @@ simplify_shift_const (x, code, result_mode, varop, input_count) else count = signed_count; - if (count >= GET_MODE_BITSIZE (shift_mode)) - count = GET_MODE_BITSIZE (shift_mode) - 1; - varop = XEXP (varop, 0); continue; } |