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| author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2017-08-07 00:53:06 +0200 |
|---|---|---|
| committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2018-08-08 09:55:12 +0200 |
| commit | 616b8d3d171eb1d17a2854ff75ec1380eda4e68d (patch) | |
| tree | abf33832a1d8c2725022ffa6256e8d57fd918f08 | |
| parent | 52b7cd665eb13098ea8ccd45ccac2bb5b85f423d (diff) | |
| download | sparse-dev-616b8d3d171eb1d17a2854ff75ec1380eda4e68d.tar.gz | |
simplify ((x & M') | y ) & M into (y & M) when (M' & M) == 0
This is a common pattern for bitfield simplification.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
| -rw-r--r-- | simplify.c | 23 | ||||
| -rw-r--r-- | validation/optim/mask-out.c | 1 |
2 files changed, 23 insertions, 1 deletions
@@ -775,18 +775,41 @@ static int simplify_seteq_setne(struct instruction *insn, long long value) return 0; } +static int simplify_and_or_mask(struct instruction *insn, pseudo_t and, pseudo_t other, unsigned long long mask) +{ + struct instruction *def = and->def; + + if (!constant(def->src2)) + return 0; + if (def->src2->value & mask) + return 0; + return replace_pseudo(insn, &insn->src1, other); +} + static int simplify_constant_mask(struct instruction *insn, unsigned long long mask) { pseudo_t old = insn->src1; unsigned long long omask; unsigned long long nmask; struct instruction *def; + pseudo_t src1, src2; int osize; switch (DEF_OPCODE(def, old)) { case OP_FPCMP ... OP_BINCMP_END: osize = 1; goto oldsize; + case OP_OR: + // Let's handle ((A & M') | B ) & M + // or (B | (A & M')) & M + // when M' & M == 0 + src1 = def->src1; + src2 = def->src2; + if (def_opcode(src1) == OP_AND) + return simplify_and_or_mask(insn, src1, src2, mask); + if (def_opcode(src2) == OP_AND) + return simplify_and_or_mask(insn, src2, src1, mask); + break; case OP_ZEXT: osize = def->orig_type->bit_size; /* fall through */ diff --git a/validation/optim/mask-out.c b/validation/optim/mask-out.c index bf116873..ac85aec8 100644 --- a/validation/optim/mask-out.c +++ b/validation/optim/mask-out.c @@ -6,7 +6,6 @@ unsigned mask(unsigned a, unsigned b) /* * check-name: mask-out * check-command: test-linearize -Wno-decl $file - * check-known-to-fail * * check-output-ignore * check-output-excludes: %arg1 |