return false;
}
+/* A subroutine of s390_expand_cs_hqi which returns a register which holds VAL
+ of mode MODE shifted by COUNT bits. */
+
+static inline rtx
+s390_expand_mask_and_shift (rtx val, enum machine_mode mode, rtx count)
+{
+ val = expand_simple_binop (SImode, AND, val, GEN_INT (GET_MODE_MASK (mode)),
+ NULL_RTX, 1, OPTAB_DIRECT);
+ return expand_simple_binop (SImode, ASHIFT, val, count,
+ NULL_RTX, 1, OPTAB_DIRECT);
+}
+
+/* Structure to hold the initial parameters for a compare_and_swap operation
+ in HImode and QImode. */
+
+struct alignment_context
+{
+ rtx memsi; /* SI aligned memory location. */
+ rtx shift; /* Bit offset with regard to lsb. */
+ rtx modemask; /* Mask of the HQImode shifted by SHIFT bits. */
+ rtx modemaski; /* ~modemask */
+ bool aligned; /* True if memory is aliged, false else. */
+};
+
+/* A subroutine of s390_expand_cs_hqi to initialize the structure AC for
+ transparent simplifying, if the memory alignment is known to be at least
+ 32bit. MEM is the memory location for the actual operation and MODE its
+ mode. */
+
+static void
+init_alignment_context (struct alignment_context *ac, rtx mem,
+ enum machine_mode mode)
+{
+ ac->shift = GEN_INT (GET_MODE_SIZE (SImode) - GET_MODE_SIZE (mode));
+ ac->aligned = (MEM_ALIGN (mem) >= GET_MODE_BITSIZE (SImode));
+
+ if (ac->aligned)
+ ac->memsi = adjust_address (mem, SImode, 0); /* Memory is aligned. */
+ else
+ {
+ /* Alignment is unknown. */
+ rtx byteoffset, addr, align;
+
+ /* Force the address into a register. */
+ addr = force_reg (Pmode, XEXP (mem, 0));
+
+ /* Align it to SImode. */
+ align = expand_simple_binop (Pmode, AND, addr,
+ GEN_INT (-GET_MODE_SIZE (SImode)),
+ NULL_RTX, 1, OPTAB_DIRECT);
+ /* Generate MEM. */
+ ac->memsi = gen_rtx_MEM (SImode, align);
+ MEM_VOLATILE_P (ac->memsi) = MEM_VOLATILE_P (mem);
+ set_mem_align (ac->memsi, GET_MODE_BITSIZE (SImode));
+
+ /* Calculate shiftcount. */
+ byteoffset = expand_simple_binop (Pmode, AND, addr,
+ GEN_INT (GET_MODE_SIZE (SImode) - 1),
+ NULL_RTX, 1, OPTAB_DIRECT);
+ /* As we already have some offset, evaluate the remaining distance. */
+ ac->shift = expand_simple_binop (SImode, MINUS, ac->shift, byteoffset,
+ NULL_RTX, 1, OPTAB_DIRECT);
+
+ }
+ /* Shift is the byte count, but we need the bitcount. */
+ ac->shift = expand_simple_binop (SImode, MULT, ac->shift, GEN_INT (BITS_PER_UNIT),
+ NULL_RTX, 1, OPTAB_DIRECT);
+ /* Calculate masks. */
+ ac->modemask = expand_simple_binop (SImode, ASHIFT,
+ GEN_INT (GET_MODE_MASK (mode)), ac->shift,
+ NULL_RTX, 1, OPTAB_DIRECT);
+ ac->modemaski = expand_simple_unop (SImode, NOT, ac->modemask, NULL_RTX, 1);
+}
+
+/* Expand an atomic compare and swap operation for HImode and QImode. MEM is
+ the memory location, CMP the old value to compare MEM with and NEW the value
+ to set if CMP == MEM.
+ CMP is never in memory for compare_and_swap_cc because
+ expand_bool_compare_and_swap puts it into a register for later compare. */
+
+void
+s390_expand_cs_hqi (enum machine_mode mode, rtx target, rtx mem, rtx cmp, rtx new)
+{
+ struct alignment_context ac;
+ rtx cmpv, newv, val, resv, cc;
+ rtx res = gen_reg_rtx (SImode);
+ rtx csloop = gen_label_rtx ();
+ rtx csend = gen_label_rtx ();
+
+ gcc_assert (register_operand (target, VOIDmode));
+ gcc_assert (MEM_P (mem));
+
+ init_alignment_context (&ac, mem, mode);
+
+ /* Shift the values to the correct bit positions. */
+ if (!(ac.aligned && MEM_P (cmp)))
+ cmp = s390_expand_mask_and_shift (cmp, mode, ac.shift);
+ if (!(ac.aligned && MEM_P (new)))
+ new = s390_expand_mask_and_shift (new, mode, ac.shift);
+
+ /* Load full word. Subsequent loads are performed by CS. */
+ val = expand_simple_binop (SImode, AND, ac.memsi, ac.modemaski,
+ NULL_RTX, 1, OPTAB_DIRECT);
+
+ /* Start CS loop. */
+ emit_label (csloop);
+ /* val = "<mem>00..0<mem>"
+ * cmp = "00..0<cmp>00..0"
+ * new = "00..0<new>00..0"
+ */
+
+ /* Patch cmp and new with val at correct position. */
+ if (ac.aligned && MEM_P (cmp))
+ {
+ cmpv = force_reg (SImode, val);
+ store_bit_field (cmpv, GET_MODE_BITSIZE (mode), 0, SImode, cmp);
+ }
+ else
+ cmpv = force_reg (SImode, expand_simple_binop (SImode, IOR, cmp, val,
+ NULL_RTX, 1, OPTAB_DIRECT));
+ if (ac.aligned && MEM_P (new))
+ {
+ newv = force_reg (SImode, val);
+ store_bit_field (newv, GET_MODE_BITSIZE (mode), 0, SImode, new);
+ }
+ else
+ newv = force_reg (SImode, expand_simple_binop (SImode, IOR, new, val,
+ NULL_RTX, 1, OPTAB_DIRECT));
+
+ /* Emit compare_and_swap pattern. */
+ emit_insn (gen_sync_compare_and_swap_ccsi (res, ac.memsi, cmpv, newv));
+
+ /* Jump to end if we're done (likely?). */
+ s390_emit_jump (csend, s390_emit_compare (EQ, cmpv, ac.memsi));
+
+ /* Check for changes outside mode. */
+ resv = expand_simple_binop (SImode, AND, res, ac.modemaski,
+ NULL_RTX, 1, OPTAB_DIRECT);
+ cc = s390_emit_compare (NE, resv, val);
+ emit_move_insn (val, resv);
+ /* Loop internal if so. */
+ s390_emit_jump (csloop, cc);
+
+ emit_label (csend);
+
+ /* Return the correct part of the bitfield. */
+ convert_move (target, expand_simple_binop (SImode, LSHIFTRT, res, ac.shift,
+ NULL_RTX, 1, OPTAB_DIRECT), 1);
+}
+
/* This is called from dwarf2out.c via TARGET_ASM_OUTPUT_DWARF_DTPREL.
We need to emit DTP-relative relocations. */
projects / thirdparty / gcc.git / commitdiff
