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| author | Jakub Jelinek <jakub@redhat.com> | 2013-07-08 10:48:40 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2013-07-08 10:48:40 +0200 |
| commit | 8140c06592fe11cfb82c54f0dc467705381a8785 (patch) | |
| tree | 38579d40ff3a272b2669af830c79e5de77e39b55 /gcc/simplify-rtx.c | |
| parent | 78d432da45406aaeb97b7485f548d07fc3ca7049 (diff) | |
| download | gcc-8140c06592fe11cfb82c54f0dc467705381a8785.zip gcc-8140c06592fe11cfb82c54f0dc467705381a8785.tar.gz gcc-8140c06592fe11cfb82c54f0dc467705381a8785.tar.bz2 | |
re PR target/57819 (Suboptimal shift patterns)
PR target/57819
* simplify-rtx.c (simplify_unary_operation_1) <case ZERO_EXTEND>:
Simplify (zero_extend:SI (subreg:QI (and:SI (reg:SI)
(const_int 63)) 0)).
* combine.c (make_extraction): Create ZERO_EXTEND or SIGN_EXTEND
using simplify_gen_unary instead of gen_rtx_*_EXTEND.
* config/i386/i386.md (*jcc_bt<mode>_1): New define_insn_and_split.
* gcc.target/i386/pr57819.c: New test.
From-SVN: r200775
Diffstat (limited to 'gcc/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index be54db8..17a3d12 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -1470,6 +1470,29 @@ simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op) } } + /* (zero_extend:M (subreg:N <X:O>)) is <X:O> (for M == O) or + (zero_extend:M <X:O>), if X doesn't have any non-zero bits outside + of mode N. E.g. + (zero_extend:SI (subreg:QI (and:SI (reg:SI) (const_int 63)) 0)) is + (and:SI (reg:SI) (const_int 63)). */ + if (GET_CODE (op) == SUBREG + && GET_MODE_PRECISION (GET_MODE (op)) + < GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op))) + && GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op))) + <= HOST_BITS_PER_WIDE_INT + && GET_MODE_PRECISION (mode) + >= GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op))) + && subreg_lowpart_p (op) + && (nonzero_bits (SUBREG_REG (op), GET_MODE (SUBREG_REG (op))) + & ~GET_MODE_MASK (GET_MODE (op))) == 0) + { + if (GET_MODE_PRECISION (mode) + == GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op)))) + return SUBREG_REG (op); + return simplify_gen_unary (ZERO_EXTEND, mode, SUBREG_REG (op), + GET_MODE (SUBREG_REG (op))); + } + #if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend) /* As we do not know which address space the pointer is referring to, we can do this only if the target does not support different pointer |