diff options
Diffstat (limited to 'contrib/gcc/loop.c')
| -rw-r--r-- | contrib/gcc/loop.c | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/contrib/gcc/loop.c b/contrib/gcc/loop.c index 284d891cf21e..c0888fa6ce28 100644 --- a/contrib/gcc/loop.c +++ b/contrib/gcc/loop.c @@ -6275,7 +6275,7 @@ basic_induction_var (loop, x, mode, dest_reg, p, inc_val, mult_val, location) { enum rtx_code code; rtx *argp, arg; - rtx insn, set = 0; + rtx insn, set = 0, last, inc; code = GET_CODE (x); *location = NULL; @@ -6303,7 +6303,26 @@ basic_induction_var (loop, x, mode, dest_reg, p, inc_val, mult_val, location) if (loop_invariant_p (loop, arg) != 1) return 0; - *inc_val = convert_modes (GET_MODE (dest_reg), GET_MODE (x), arg, 0); + /* convert_modes can emit new instructions, e.g. when arg is a loop + invariant MEM and dest_reg has a different mode. + These instructions would be emitted after the end of the function + and then *inc_val would be an unitialized pseudo. + Detect this and bail in this case. + Other alternatives to solve this can be introducing a convert_modes + variant which is allowed to fail but not allowed to emit new + instructions, emit these instructions before loop start and let + it be garbage collected if *inc_val is never used or saving the + *inc_val initialization sequence generated here and when *inc_val + is going to be actually used, emit it at some suitable place. */ + last = get_last_insn (); + inc = convert_modes (GET_MODE (dest_reg), GET_MODE (x), arg, 0); + if (get_last_insn () != last) + { + delete_insns_since (last); + return 0; + } + + *inc_val = inc; *mult_val = const1_rtx; *location = argp; return 1; @@ -6384,7 +6403,15 @@ basic_induction_var (loop, x, mode, dest_reg, p, inc_val, mult_val, location) && GET_MODE_CLASS (mode) != MODE_CC) { /* Possible bug here? Perhaps we don't know the mode of X. */ - *inc_val = convert_modes (GET_MODE (dest_reg), mode, x, 0); + last = get_last_insn (); + inc = convert_modes (GET_MODE (dest_reg), mode, x, 0); + if (get_last_insn () != last) + { + delete_insns_since (last); + return 0; + } + + *inc_val = inc; *mult_val = const0_rtx; return 1; } |