diff options
Diffstat (limited to 'gcc/ira.c')
| -rw-r--r-- | gcc/ira.c | 60 |
1 files changed, 40 insertions, 20 deletions
@@ -4037,16 +4037,27 @@ pseudo_for_reload_consideration_p (int regno) return (reg_renumber[regno] >= 0 || ira_conflicts_p); } -/* Init LIVE_SUBREGS[ALLOCNUM] and LIVE_SUBREGS_USED[ALLOCNUM] using - REG to the number of nregs, and INIT_VALUE to get the - initialization. ALLOCNUM need not be the regno of REG. */ +/* Return true if we can track the individual bytes of subreg X. + When returning true, set *OUTER_SIZE to the number of bytes in + X itself, *INNER_SIZE to the number of bytes in the inner register + and *START to the offset of the first byte. */ +static bool +get_subreg_tracking_sizes (rtx x, HOST_WIDE_INT *outer_size, + HOST_WIDE_INT *inner_size, HOST_WIDE_INT *start) +{ + rtx reg = regno_reg_rtx[REGNO (SUBREG_REG (x))]; + *outer_size = GET_MODE_SIZE (GET_MODE (x)); + *inner_size = GET_MODE_SIZE (GET_MODE (reg)); + *start = SUBREG_BYTE (x); + return true; +} + +/* Init LIVE_SUBREGS[ALLOCNUM] and LIVE_SUBREGS_USED[ALLOCNUM] for + a register with SIZE bytes, making the register live if INIT_VALUE. */ static void init_live_subregs (bool init_value, sbitmap *live_subregs, - bitmap live_subregs_used, int allocnum, rtx reg) + bitmap live_subregs_used, int allocnum, int size) { - unsigned int regno = REGNO (SUBREG_REG (reg)); - int size = GET_MODE_SIZE (GET_MODE (regno_reg_rtx[regno])); - gcc_assert (size > 0); /* Been there, done that. */ @@ -4155,19 +4166,26 @@ build_insn_chain (void) && (!DF_REF_FLAGS_IS_SET (def, DF_REF_CONDITIONAL))) { rtx reg = DF_REF_REG (def); - - /* We can model subregs, but not if they are - wrapped in ZERO_EXTRACTS. */ + HOST_WIDE_INT outer_size, inner_size, start; + + /* We can usually track the liveness of individual + bytes within a subreg. The only exceptions are + subregs wrapped in ZERO_EXTRACTs and subregs whose + size is not known; in those cases we need to be + conservative and treat the definition as a partial + definition of the full register rather than a full + definition of a specific part of the register. */ if (GET_CODE (reg) == SUBREG - && !DF_REF_FLAGS_IS_SET (def, DF_REF_ZERO_EXTRACT)) + && !DF_REF_FLAGS_IS_SET (def, DF_REF_ZERO_EXTRACT) + && get_subreg_tracking_sizes (reg, &outer_size, + &inner_size, &start)) { - unsigned int start = SUBREG_BYTE (reg); - unsigned int last = start - + GET_MODE_SIZE (GET_MODE (reg)); + HOST_WIDE_INT last = start + outer_size; init_live_subregs (bitmap_bit_p (live_relevant_regs, regno), - live_subregs, live_subregs_used, regno, reg); + live_subregs, live_subregs_used, regno, + inner_size); if (!DF_REF_FLAGS_IS_SET (def, DF_REF_STRICT_LOW_PART)) @@ -4252,18 +4270,20 @@ build_insn_chain (void) if (regno < FIRST_PSEUDO_REGISTER || pseudo_for_reload_consideration_p (regno)) { + HOST_WIDE_INT outer_size, inner_size, start; if (GET_CODE (reg) == SUBREG && !DF_REF_FLAGS_IS_SET (use, DF_REF_SIGN_EXTRACT - | DF_REF_ZERO_EXTRACT)) + | DF_REF_ZERO_EXTRACT) + && get_subreg_tracking_sizes (reg, &outer_size, + &inner_size, &start)) { - unsigned int start = SUBREG_BYTE (reg); - unsigned int last = start - + GET_MODE_SIZE (GET_MODE (reg)); + HOST_WIDE_INT last = start + outer_size; init_live_subregs (bitmap_bit_p (live_relevant_regs, regno), - live_subregs, live_subregs_used, regno, reg); + live_subregs, live_subregs_used, regno, + inner_size); /* Ignore the paradoxical bits. */ if (last > SBITMAP_SIZE (live_subregs[regno])) |