diff options
Diffstat (limited to 'gnu/usr.bin/gcc/loop.c')
| -rw-r--r-- | gnu/usr.bin/gcc/loop.c | 36 |
1 files changed, 27 insertions, 9 deletions
diff --git a/gnu/usr.bin/gcc/loop.c b/gnu/usr.bin/gcc/loop.c index c87f1c33eec..3e780203977 100644 --- a/gnu/usr.bin/gcc/loop.c +++ b/gnu/usr.bin/gcc/loop.c @@ -6042,13 +6042,16 @@ maybe_eliminate_biv_1 (x, insn, bl, eliminate_p, where) { /* Can replace with any giv that was reduced and that has (MULT_VAL != 0) and (ADD_VAL == 0). - Require a constant for MULT_VAL, so we know it's nonzero. */ + Require a constant for MULT_VAL, so we know it's nonzero. + ??? We disable this optimization to avoid potential + overflows. */ for (v = bl->giv; v; v = v->next_iv) if (CONSTANT_P (v->mult_val) && v->mult_val != const0_rtx && v->add_val == const0_rtx && ! v->ignore && ! v->maybe_dead && v->always_computable - && v->mode == mode) + && v->mode == mode + && 0) { if (! eliminate_p) return 1; @@ -6068,12 +6071,19 @@ maybe_eliminate_biv_1 (x, insn, bl, eliminate_p, where) /* Look for a giv with (MULT_VAL != 0) and (ADD_VAL != 0); replace test insn with a compare insn (cmp REDUCED_GIV ADD_VAL). - Require a constant for MULT_VAL, so we know it's nonzero. */ + Require a constant for MULT_VAL, so we know it's nonzero. + ??? Do this only if ADD_VAL is a pointer to avoid a potential + overflow problem. */ for (v = bl->giv; v; v = v->next_iv) if (CONSTANT_P (v->mult_val) && v->mult_val != const0_rtx && ! v->ignore && ! v->maybe_dead && v->always_computable - && v->mode == mode) + && v->mode == mode + && (GET_CODE (v->add_val) == SYMBOL_REF + || GET_CODE (v->add_val) == LABEL_REF + || GET_CODE (v->add_val) == CONST + || (GET_CODE (v->add_val) == REG + && REGNO_POINTER_FLAG (REGNO (v->add_val))))) { if (! eliminate_p) return 1; @@ -6128,7 +6138,11 @@ maybe_eliminate_biv_1 (x, insn, bl, eliminate_p, where) for (v = bl->giv; v; v = v->next_iv) if (CONSTANT_P (v->mult_val) && INTVAL (v->mult_val) > 0 - && CONSTANT_P (v->add_val) + && (GET_CODE (v->add_val) == SYMBOL_REF + || GET_CODE (v->add_val) == LABEL_REF + || GET_CODE (v->add_val) == CONST + || (GET_CODE (v->add_val) == REG + && REGNO_POINTER_FLAG (REGNO (v->add_val)))) && ! v->ignore && ! v->maybe_dead && v->always_computable && v->mode == mode) { @@ -6161,12 +6175,14 @@ maybe_eliminate_biv_1 (x, insn, bl, eliminate_p, where) } /* Look for giv with positive constant mult_val and nonconst add_val. - Insert insns to calculate new compare value. */ + Insert insns to calculate new compare value. + ??? Turn this off due to possible overflow. */ for (v = bl->giv; v; v = v->next_iv) if (CONSTANT_P (v->mult_val) && INTVAL (v->mult_val) > 0 && ! v->ignore && ! v->maybe_dead && v->always_computable - && v->mode == mode) + && v->mode == mode + && 0) { rtx tem; @@ -6192,12 +6208,14 @@ maybe_eliminate_biv_1 (x, insn, bl, eliminate_p, where) if (invariant_p (arg) == 1) { /* Look for giv with constant positive mult_val and nonconst - add_val. Insert insns to compute new compare value. */ + add_val. Insert insns to compute new compare value. + ??? Turn this off due to possible overflow. */ for (v = bl->giv; v; v = v->next_iv) if (CONSTANT_P (v->mult_val) && INTVAL (v->mult_val) > 0 && ! v->ignore && ! v->maybe_dead && v->always_computable - && v->mode == mode) + && v->mode == mode + && 0) { rtx tem; |