diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 6b7bdd0..2de2a3e 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -8102,6 +8102,18 @@ make_compound_operation (rtx x, enum rtx_code in_code) rtx inner = SUBREG_REG (x), simplified; enum rtx_code subreg_code = in_code; + /* If the SUBREG is masking of a logical right shift, + make an extraction. */ + if (GET_CODE (inner) == LSHIFTRT + && GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (inner)) + && subreg_lowpart_p (x)) + { + new_rtx = make_compound_operation (XEXP (inner, 0), next_code); + new_rtx = make_extraction (mode, new_rtx, 0, XEXP (inner, 1), + mode_width, 1, 0, in_code == COMPARE); + break; + } + /* If in_code is COMPARE, it isn't always safe to pass it through to the recursive make_compound_operation call. */ if (subreg_code == COMPARE @@ -11994,6 +12006,29 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1) if (subreg_lowpart_p (op0) && GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0))) < mode_width) ; + else if (subreg_lowpart_p (op0) + && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT + && GET_MODE_CLASS (GET_MODE (SUBREG_REG (op0))) == MODE_INT + && (code == NE || code == EQ) + && (GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0))) + <= HOST_BITS_PER_WIDE_INT) + && !paradoxical_subreg_p (op0) + && (nonzero_bits (SUBREG_REG (op0), + GET_MODE (SUBREG_REG (op0))) + & ~GET_MODE_MASK (GET_MODE (op0))) == 0) + { + /* Remove outer subregs that don't do anything. */ + tem = gen_lowpart (GET_MODE (SUBREG_REG (op0)), op1); + + if ((nonzero_bits (tem, GET_MODE (SUBREG_REG (op0))) + & ~GET_MODE_MASK (GET_MODE (op0))) == 0) + { + op0 = SUBREG_REG (op0); + op1 = tem; + continue; + } + break; + } else break; |