diff options
Diffstat (limited to 'gcc/explow.c')
| -rw-r--r-- | gcc/explow.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/gcc/explow.c b/gcc/explow.c index 4c99d4e2871..b31e3751c6f 100644 --- a/gcc/explow.c +++ b/gcc/explow.c @@ -2011,6 +2011,13 @@ anti_adjust_stack_and_probe_stack_clash (rtx size) if (size != CONST0_RTX (Pmode) && targetm.stack_clash_protection_final_dynamic_probe (residual)) { + /* SIZE could be zero at runtime and in that case *sp could hold + live data. Furthermore, we don't want to probe into the red + zone. + + Go ahead and just guard a probe at *sp on SIZE != 0 at runtime + if SIZE is not a compile time constant. */ + /* Ideally we would just probe at *sp. However, if SIZE is not a compile-time constant, but is zero at runtime, then *sp might hold live data. So probe at *sp if we know that @@ -2023,9 +2030,12 @@ anti_adjust_stack_and_probe_stack_clash (rtx size) } else { - emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx, - -GET_MODE_SIZE (word_mode))); + rtx label = gen_label_rtx (); + emit_cmp_and_jump_insns (size, CONST0_RTX (GET_MODE (size)), + EQ, NULL_RTX, Pmode, 1, label); + emit_stack_probe (stack_pointer_rtx); emit_insn (gen_blockage ()); + emit_label (label); } } } |