diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 58 |
1 files changed, 52 insertions, 6 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 6bc921b..a96e4f7 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -1055,6 +1055,43 @@ can_combine_p (insn, i3, pred, succ, pdest, psrc) return 1; } +/* Check if PAT is an insn - or a part of it - used to set up an + argument for a function in a hard register. */ + +static int +sets_function_arg_p (pat) + rtx pat; +{ + int i; + rtx inner_dest; + + switch (GET_CODE (pat)) + { + case INSN: + return sets_function_arg_p (PATTERN (pat)); + + case PARALLEL: + for (i = XVECLEN (pat, 0); --i >= 0;) + if (sets_function_arg_p (XVECEXP (pat, 0, i))) + return 1; + + break; + + case SET: + inner_dest = SET_DEST (pat); + while (GET_CODE (inner_dest) == STRICT_LOW_PART + || GET_CODE (inner_dest) == SUBREG + || GET_CODE (inner_dest) == ZERO_EXTRACT) + inner_dest = XEXP (inner_dest, 0); + + return (GET_CODE (inner_dest) == REG + && REGNO (inner_dest) < FIRST_PSEUDO_REGISTER + && FUNCTION_ARG_REGNO_P (REGNO (inner_dest))); + } + + return 0; +} + /* LOC is the location within I3 that contains its pattern or the component of a PARALLEL of the pattern. We validate that it is valid for combining. @@ -1150,19 +1187,28 @@ combinable_i3pat (i3, loc, i2dest, i1dest, i1_not_in_src, pi3dest_killed) if ((inner_dest != dest && (reg_overlap_mentioned_p (i2dest, inner_dest) || (i1dest && reg_overlap_mentioned_p (i1dest, inner_dest)))) + /* This is the same test done in can_combine_p except that we allow a hard register with SMALL_REGISTER_CLASSES if SRC is a - CALL operation. - Moreover, we can't test all_adjacent; we don't have to, since - this instruction will stay in place, thus we are not considering - to increase the lifetime of INNER_DEST. */ + CALL operation. Moreover, we can't test all_adjacent; we don't + have to, since this instruction will stay in place, thus we are + not considering increasing the lifetime of INNER_DEST. + + Also, if this insn sets a function argument, combining it with + something that might need a spill could clobber a previous + function argument; the all_adjacent test in can_combine_p also + checks this; here, we do a more specific test for this case. */ + || (GET_CODE (inner_dest) == REG && REGNO (inner_dest) < FIRST_PSEUDO_REGISTER && (! HARD_REGNO_MODE_OK (REGNO (inner_dest), GET_MODE (inner_dest)) || (SMALL_REGISTER_CLASSES && GET_CODE (src) != CALL && ! REG_USERVAR_P (inner_dest) - && FUNCTION_VALUE_REGNO_P (REGNO (inner_dest))))) + && (FUNCTION_VALUE_REGNO_P (REGNO (inner_dest)) + || (FUNCTION_ARG_REGNO_P (REGNO (inner_dest)) + && i3 != 0 + && sets_function_arg_p (prev_nonnote_insn (i3))))))) || (i1_not_in_src && reg_overlap_mentioned_p (i1dest, src))) return 0; @@ -7188,7 +7234,7 @@ simplify_and_const_int (x, mode, varop, constop) /* We let num_sign_bit_copies recur into nonzero_bits as that is useful. We don't let nonzero_bits recur into num_sign_bit_copies, because that is less useful. We can't allow both, because that results in exponential - run time recusion. There is a nullstone testcase that triggered + run time recursion. There is a nullstone testcase that triggered this. This macro avoids accidental uses of num_sign_bit_copies. */ #define num_sign_bit_copies() |