diff options
| -rw-r--r-- | gcc/function.c | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/gcc/function.c b/gcc/function.c index ba1265b3ace..6dfc17cac1d 100644 --- a/gcc/function.c +++ b/gcc/function.c @@ -2675,7 +2675,7 @@ instantiate_virtual_regs_1 (loc, object, extra_insns) /* Handle special case of virtual register plus constant. */ if (CONSTANT_P (XEXP (x, 1))) { - rtx old; + rtx old, new_offset; /* Check for (plus (plus VIRT foo) (const_int)) first. */ if (GET_CODE (XEXP (x, 0)) == PLUS) @@ -2722,18 +2722,26 @@ instantiate_virtual_regs_1 (loc, object, extra_insns) return 1; } - old = XEXP (x, 0); - XEXP (x, 0) = new; - new = plus_constant (XEXP (x, 1), offset); + new_offset = plus_constant (XEXP (x, 1), offset); - /* If the new constant is zero, try to replace the sum with its - first operand. */ - if (new == const0_rtx - && validate_change (object, loc, XEXP (x, 0), 0)) + /* If the new constant is zero, try to replace the sum with just + the register. */ + if (new_offset == const0_rtx + && validate_change (object, loc, new, 0)) return 1; - /* Next try to replace constant with new one. */ - if (!validate_change (object, &XEXP (x, 1), new, 0)) + /* Next try to replace the register and new offset. + There are two changes to validate here and we can't assume that + in the case of old offset equals new just changing the register + will yield a valid insn. In the interests of a little efficiency, + however, we only call validate change once (we don't queue up the + changes and then call apply_change_group). */ + + old = XEXP (x, 0); + if (offset == 0 + ? ! validate_change (object, &XEXP (x, 0), new, 0) + : (XEXP (x, 0) = new, + ! validate_change (object, &XEXP (x, 1), new_offset, 0))) { if (! extra_insns) { @@ -2744,15 +2752,16 @@ instantiate_virtual_regs_1 (loc, object, extra_insns) /* Otherwise copy the new constant into a register and replace constant with that register. */ temp = gen_reg_rtx (Pmode); + XEXP (x, 0) = new; if (validate_change (object, &XEXP (x, 1), temp, 0)) - emit_insn_before (gen_move_insn (temp, new), object); + emit_insn_before (gen_move_insn (temp, new_offset), object); else { /* If that didn't work, replace this expression with a register containing the sum. */ - new = gen_rtx (PLUS, Pmode, XEXP (x, 0), new); XEXP (x, 0) = old; + new = gen_rtx (PLUS, Pmode, new, new_offset); start_sequence (); temp = force_operand (new, NULL_RTX); |
