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| author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2021-02-09 02:36:14 +0100 |
|---|---|---|
| committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2021-04-18 17:21:37 +0200 |
| commit | df7767c6c57284ec3deda589f3694d2170b21fd6 (patch) | |
| tree | ad444f1cd7ec2aa07f2e6c8d7b7e5654018e5ec3 | |
| parent | 28cd6d609ea460c6138f8cd17f89fc9885fb7dc2 (diff) | |
| download | sparse-df7767c6c57284ec3deda589f3694d2170b21fd6.tar.gz | |
simplify AND(x >= 0, x < C) --> (unsigned)x < C
Such compares with a signed value are relatively common and can be
easily be simplified into a single unsigned compare. So, do it.
Note: This simplification triggers only 27 times in a x86-64 defconfig
kernel. I expected more but I suppose it's because most checks
aren't done against a constant or are done with unsigned values.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
| -rw-r--r-- | simplify.c | 11 | ||||
| -rw-r--r-- | validation/optim/range-check1.c | 1 | ||||
| -rw-r--r-- | validation/optim/range-check2.c | 1 |
3 files changed, 11 insertions, 2 deletions
@@ -1920,6 +1920,17 @@ static int simplify_and_one_side(struct instruction *insn, pseudo_t *p1, pseudo_ if (def->src1 == defr->src1 && def->src2 == defr->src2) return replace_with_value(insn, 0); } + if (def->opcode == OP_SET_GE && is_zero(def->src2)) { + switch (DEF_OPCODE(defr, *p2)) { + case OP_SET_LE: + if (!is_positive(defr->src2, defr->itype->bit_size)) + break; + // (x >= 0) && (x <= C) --> (x u<= C) + insn->itype = defr->itype; + replace_binop(insn, OP_SET_BE, &insn->src1, defr->src1, &insn->src2, defr->src2); + return REPEAT_CSE; + } + } break; case OP_OR: if (DEF_OPCODE(defr, *p2) == OP_OR) { diff --git a/validation/optim/range-check1.c b/validation/optim/range-check1.c index 82b93991..358da045 100644 --- a/validation/optim/range-check1.c +++ b/validation/optim/range-check1.c @@ -8,7 +8,6 @@ _Bool check_ok(long i) /* * check-name: range-check1 * check-command: test-linearize -Wno-decl $file - * check-known-to-fail * * check-output-ignore * check-output-contains: setbe\\..*0x3ff diff --git a/validation/optim/range-check2.c b/validation/optim/range-check2.c index f565b84e..69c01b9d 100644 --- a/validation/optim/range-check2.c +++ b/validation/optim/range-check2.c @@ -8,7 +8,6 @@ _Bool check_ok(int i) /* * check-name: range-check2 * check-command: test-linearize -Wno-decl $file - * check-known-to-fail * * check-output-ignore * check-output-returns: 1 |