diff options
Diffstat (limited to 'gcc/cse.c')
| -rw-r--r-- | gcc/cse.c | 49 |
1 files changed, 42 insertions, 7 deletions
diff --git a/gcc/cse.c b/gcc/cse.c index 255c4dbea4c..b06c6693d02 100644 --- a/gcc/cse.c +++ b/gcc/cse.c @@ -4524,14 +4524,49 @@ cse_insn (rtx_insn *insn) canonicalize_insn (insn, &sets, n_sets); /* If this insn has a REG_EQUAL note, store the equivalent value in SRC_EQV, - if different, or if the DEST is a STRICT_LOW_PART. The latter condition - is necessary because SRC_EQV is handled specially for this case, and if - it isn't set, then there will be no equivalence for the destination. */ + if different, or if the DEST is a STRICT_LOW_PART/ZERO_EXTRACT. The + latter condition is necessary because SRC_EQV is handled specially for + this case, and if it isn't set, then there will be no equivalence + for the destination. */ if (n_sets == 1 && REG_NOTES (insn) != 0 - && (tem = find_reg_note (insn, REG_EQUAL, NULL_RTX)) != 0 - && (! rtx_equal_p (XEXP (tem, 0), SET_SRC (sets[0].rtl)) - || GET_CODE (SET_DEST (sets[0].rtl)) == STRICT_LOW_PART)) - src_eqv = copy_rtx (XEXP (tem, 0)); + && (tem = find_reg_note (insn, REG_EQUAL, NULL_RTX)) != 0) + { + if ((! rtx_equal_p (XEXP (tem, 0), SET_SRC (sets[0].rtl))) + || GET_CODE (SET_DEST (sets[0].rtl)) == STRICT_LOW_PART) + src_eqv = copy_rtx (XEXP (tem, 0)); + + /* If DEST is of the form ZERO_EXTACT, as in: + (set (zero_extract:SI (reg:SI 119) + (const_int 16 [0x10]) + (const_int 16 [0x10])) + (const_int 51154 [0xc7d2])) + REG_EQUAL note will specify the value of register (reg:SI 119) at this + point. Note that this is different from SRC_EQV. We can however + calculate SRC_EQV with the position and width of ZERO_EXTRACT. */ + else if (GET_CODE (SET_DEST (sets[0].rtl)) == ZERO_EXTRACT + && CONST_INT_P (src_eqv) + && CONST_INT_P (XEXP (SET_DEST (sets[0].rtl), 1)) + && CONST_INT_P (XEXP (SET_DEST (sets[0].rtl), 2))) + { + rtx dest_reg = XEXP (SET_DEST (sets[0].rtl), 0); + rtx width = XEXP (SET_DEST (sets[0].rtl), 1); + rtx pos = XEXP (SET_DEST (sets[0].rtl), 2); + HOST_WIDE_INT val = INTVAL (src_eqv); + HOST_WIDE_INT mask; + unsigned int shift; + if (BITS_BIG_ENDIAN) + shift = GET_MODE_PRECISION (GET_MODE (dest_reg)) + - INTVAL (pos) - INTVAL (width); + else + shift = INTVAL (pos); + if (INTVAL (width) == HOST_BITS_PER_WIDE_INT) + mask = ~(HOST_WIDE_INT) 0; + else + mask = ((HOST_WIDE_INT) 1 << INTVAL (width)) - 1; + val = (val >> shift) & mask; + src_eqv = GEN_INT (val); + } + } /* Set sets[i].src_elt to the class each source belongs to. Detect assignments from or to volatile things |