diff options
Diffstat (limited to 'gcc/regmove.c')
| -rw-r--r-- | gcc/regmove.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/gcc/regmove.c b/gcc/regmove.c index ab1a469..a411183 100644 --- a/gcc/regmove.c +++ b/gcc/regmove.c @@ -1117,23 +1117,28 @@ regmove_backward_pass (void) break; } - /* We can't make this change if SRC is read or + /* We can't make this change if DST is mentioned at + all in P, since we are going to change its value. + We can't make this change if SRC is read or partially written in P, since we are going to - eliminate SRC. We can't make this change - if DST is mentioned at all in P, - since we are going to change its value. */ - if (reg_overlap_mentioned_p (src, PATTERN (p))) + eliminate SRC. However, if it's a debug insn, we + can't refrain from making the change, for this + would cause codegen differences, so instead we + invalidate debug expressions that reference DST, + and adjust references to SRC in them so that they + become references to DST. */ + if (reg_mentioned_p (dst, PATTERN (p))) { if (DEBUG_INSN_P (p)) - validate_replace_rtx_group (dst, src, insn); + validate_change (p, &INSN_VAR_LOCATION_LOC (p), + gen_rtx_UNKNOWN_VAR_LOC (), 1); else break; } - if (reg_mentioned_p (dst, PATTERN (p))) + if (reg_overlap_mentioned_p (src, PATTERN (p))) { if (DEBUG_INSN_P (p)) - validate_change (p, &INSN_VAR_LOCATION_LOC (p), - gen_rtx_UNKNOWN_VAR_LOC (), 1); + validate_replace_rtx_group (src, dst, p); else break; } |