diff options
Diffstat (limited to 'gcc/cse.c')
| -rw-r--r-- | gcc/cse.c | 16 |
1 files changed, 7 insertions, 9 deletions
@@ -6575,8 +6575,9 @@ check_for_label_ref (rtx *rtl, void *data) Don't count a usage of DEST, which is the SET_DEST of a SET which contains X in its SET_SRC. This is because such a SET does not modify the liveness of DEST. - DEST is set to pc_rtx for a trapping insn, which means that we must count - uses of a SET_DEST regardless because the insn can't be deleted here. */ + DEST is set to pc_rtx for a trapping insn, or for an insn with side effects. + We must then count uses of a SET_DEST regardless, because the insn can't be + deleted here. */ static void count_reg_usage (rtx x, int *counts, rtx dest, int incr) @@ -6629,9 +6630,10 @@ count_reg_usage (rtx x, int *counts, rtx dest, int incr) case CALL_INSN: case INSN: case JUMP_INSN: - /* We expect dest to be NULL_RTX here. If the insn may trap, mark - this fact by setting DEST to pc_rtx. */ - if (insn_could_throw_p (x)) + /* We expect dest to be NULL_RTX here. If the insn may trap, + or if it cannot be deleted due to side-effects, mark this fact + by setting DEST to pc_rtx. */ + if (insn_could_throw_p (x) || side_effects_p (PATTERN (x))) dest = pc_rtx; if (code == CALL_INSN) count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, dest, incr); @@ -6671,10 +6673,6 @@ count_reg_usage (rtx x, int *counts, rtx dest, int incr) return; case ASM_OPERANDS: - /* If the asm is volatile, then this insn cannot be deleted, - and so the inputs *must* be live. */ - if (MEM_VOLATILE_P (x)) - dest = NULL_RTX; /* Iterate over just the inputs, not the constraints as well. */ for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--) count_reg_usage (ASM_OPERANDS_INPUT (x, i), counts, dest, incr); |