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| author | Michael Forney <mforney@mforney.org> | 2021-06-16 20:27:49 -0700 |
|---|---|---|
| committer | Quentin Carbonneaux <quentin@c9x.me> | 2021-06-17 22:16:42 +0200 |
| commit | 6d9ee1389572ae985f6a39bb99dbd10cdf42c123 (patch) | |
| tree | 18d0ad17085f2fd6702d168d676a7716eafafae2 /amd64 | |
| parent | e0b94a3d6ade2f99ded481318e9e6d9f16953662 (diff) | |
| download | roux-6d9ee1389572ae985f6a39bb99dbd10cdf42c123.tar.gz | |
amd64: fix conditional jump when compare is swapped and used elsewhere
selcmp may potentially swap the arguments and return 1 indicating that the opposite operation should be used. However, if the compare result is used for a conditional jump as well as elsewhere, the original compare op is used instead of the opposite. To fix this, add a check to see whether the opposite compare should be used, regardless of whether selcmp() is done now, or later on during sel(). Bug report and test case from Charlie Stanton.
Diffstat (limited to 'amd64')
| -rw-r--r-- | amd64/isel.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/amd64/isel.c b/amd64/isel.c index 56e4cf3..5f84561 100644 --- a/amd64/isel.c +++ b/amd64/isel.c @@ -383,9 +383,10 @@ seljmp(Blk *b, Fn *fn) b->jmp.type = Jjf + Cine; } else if (iscmp(fi->op, &k, &c)) { + if (rtype(fi->arg[0]) == RCon) + c = cmpop(c); if (t->nuse == 1) { - if (selcmp(fi->arg, k, fn)) - c = cmpop(c); + selcmp(fi->arg, k, fn); *fi = (Ins){.op = Onop}; } b->jmp.type = Jjf + c; |