diff options
Diffstat (limited to 'gcc/cse.c')
| -rw-r--r-- | gcc/cse.c | 64 |
1 files changed, 40 insertions, 24 deletions
@@ -618,7 +618,7 @@ static rtx cse_process_notes (rtx, rtx); static void invalidate_skipped_set (rtx, rtx, void *); static void invalidate_skipped_block (rtx); static rtx cse_basic_block (rtx, rtx, struct branch_path *); -static void count_reg_usage (rtx, int *, int); +static void count_reg_usage (rtx, int *, rtx, int); static int check_for_label_ref (rtx *, void *); extern void dump_class (struct table_elt*); static void get_cse_reg_info_1 (unsigned int regno); @@ -7079,10 +7079,16 @@ check_for_label_ref (rtx *rtl, void *data) /* Count the number of times registers are used (not set) in X. COUNTS is an array in which we accumulate the count, INCR is how much - we count each register usage. */ + we count each register usage. + + Don't count a usage of DEST, which is the SET_DEST of a SET which + contains X in its SET_SRC. This is because such a SET does not + modify the liveness of DEST. + DEST is set to pc_rtx for a trapping insn, which means that we must count + uses of a SET_DEST regardless because the insn can't be deleted here. */ static void -count_reg_usage (rtx x, int *counts, int incr) +count_reg_usage (rtx x, int *counts, rtx dest, int incr) { enum rtx_code code; rtx note; @@ -7095,7 +7101,8 @@ count_reg_usage (rtx x, int *counts, int incr) switch (code = GET_CODE (x)) { case REG: - counts[REGNO (x)] += incr; + if (x != dest) + counts[REGNO (x)] += incr; return; case PC: @@ -7112,23 +7119,28 @@ count_reg_usage (rtx x, int *counts, int incr) /* If we are clobbering a MEM, mark any registers inside the address as being used. */ if (MEM_P (XEXP (x, 0))) - count_reg_usage (XEXP (XEXP (x, 0), 0), counts, incr); + count_reg_usage (XEXP (XEXP (x, 0), 0), counts, NULL_RTX, incr); return; case SET: /* Unless we are setting a REG, count everything in SET_DEST. */ if (!REG_P (SET_DEST (x))) - count_reg_usage (SET_DEST (x), counts, incr); - count_reg_usage (SET_SRC (x), counts, incr); + count_reg_usage (SET_DEST (x), counts, NULL_RTX, incr); + count_reg_usage (SET_SRC (x), counts, + dest ? dest : SET_DEST (x), + incr); return; case CALL_INSN: - count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, incr); - /* Fall through. */ - case INSN: case JUMP_INSN: - count_reg_usage (PATTERN (x), counts, incr); + /* We expect dest to be NULL_RTX here. If the insn may trap, mark + this fact by setting DEST to pc_rtx. */ + if (flag_non_call_exceptions && may_trap_p (PATTERN (x))) + dest = pc_rtx; + if (code == CALL_INSN) + count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, dest, incr); + count_reg_usage (PATTERN (x), counts, dest, incr); /* Things used in a REG_EQUAL note aren't dead since loop may try to use them. */ @@ -7143,12 +7155,12 @@ count_reg_usage (rtx x, int *counts, int incr) Process all the arguments. */ do { - count_reg_usage (XEXP (eqv, 0), counts, incr); + count_reg_usage (XEXP (eqv, 0), counts, dest, incr); eqv = XEXP (eqv, 1); } while (eqv && GET_CODE (eqv) == EXPR_LIST); else - count_reg_usage (eqv, counts, incr); + count_reg_usage (eqv, counts, dest, incr); } return; @@ -7158,15 +7170,19 @@ count_reg_usage (rtx x, int *counts, int incr) /* FUNCTION_USAGE expression lists may include (CLOBBER (mem /u)), involving registers in the address. */ || GET_CODE (XEXP (x, 0)) == CLOBBER) - count_reg_usage (XEXP (x, 0), counts, incr); + count_reg_usage (XEXP (x, 0), counts, NULL_RTX, incr); - count_reg_usage (XEXP (x, 1), counts, incr); + count_reg_usage (XEXP (x, 1), counts, NULL_RTX, incr); return; case ASM_OPERANDS: + /* If the asm is volatile, then this insn cannot be deleted, + and so the inputs *must* be live. */ + if (MEM_VOLATILE_P (x)) + dest = NULL_RTX; /* Iterate over just the inputs, not the constraints as well. */ for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--) - count_reg_usage (ASM_OPERANDS_INPUT (x, i), counts, incr); + count_reg_usage (ASM_OPERANDS_INPUT (x, i), counts, dest, incr); return; case INSN_LIST: @@ -7180,10 +7196,10 @@ count_reg_usage (rtx x, int *counts, int incr) for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) { if (fmt[i] == 'e') - count_reg_usage (XEXP (x, i), counts, incr); + count_reg_usage (XEXP (x, i), counts, dest, incr); else if (fmt[i] == 'E') for (j = XVECLEN (x, i) - 1; j >= 0; j--) - count_reg_usage (XVECEXP (x, i, j), counts, incr); + count_reg_usage (XVECEXP (x, i, j), counts, dest, incr); } } @@ -7270,11 +7286,11 @@ dead_libcall_p (rtx insn, int *counts) new = XEXP (note, 0); /* While changing insn, we must update the counts accordingly. */ - count_reg_usage (insn, counts, -1); + count_reg_usage (insn, counts, NULL_RTX, -1); if (validate_change (insn, &SET_SRC (set), new, 0)) { - count_reg_usage (insn, counts, 1); + count_reg_usage (insn, counts, NULL_RTX, 1); remove_note (insn, find_reg_note (insn, REG_RETVAL, NULL_RTX)); remove_note (insn, note); return true; @@ -7285,14 +7301,14 @@ dead_libcall_p (rtx insn, int *counts) new = force_const_mem (GET_MODE (SET_DEST (set)), new); if (new && validate_change (insn, &SET_SRC (set), new, 0)) { - count_reg_usage (insn, counts, 1); + count_reg_usage (insn, counts, NULL_RTX, 1); remove_note (insn, find_reg_note (insn, REG_RETVAL, NULL_RTX)); remove_note (insn, note); return true; } } - count_reg_usage (insn, counts, 1); + count_reg_usage (insn, counts, NULL_RTX, 1); return false; } @@ -7317,7 +7333,7 @@ delete_trivially_dead_insns (rtx insns, int nreg) counts = xcalloc (nreg, sizeof (int)); for (insn = insns; insn; insn = NEXT_INSN (insn)) if (INSN_P (insn)) - count_reg_usage (insn, counts, 1); + count_reg_usage (insn, counts, NULL_RTX, 1); /* Go from the last insn to the first and delete insns that only set unused registers or copy a register to itself. As we delete an insn, remove @@ -7355,7 +7371,7 @@ delete_trivially_dead_insns (rtx insns, int nreg) if (! live_insn) { - count_reg_usage (insn, counts, -1); + count_reg_usage (insn, counts, NULL_RTX, -1); delete_insn_and_edges (insn); ndead++; } |