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author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2021-03-13 14:03:20 +0100 |
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committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2021-04-18 23:45:41 +0200 |
commit | 99bf609861c3bc9ba313a81642988da92838c9e2 (patch) | |
tree | db342d7d500b04e2029f175a87ac952401db6728 | |
parent | eb4cdd21b7d0cedbbeff7f70e24473706ccce5a6 (diff) | |
download | sparse-99bf609861c3bc9ba313a81642988da92838c9e2.tar.gz |
TRUNC(x) {==,!=} C --> AND(x,M) {==,!=} C
It's not 100% clear than this is indeed a simplification but:
1) from a pure instruction count point of view, it doesn't make
things worst
2) in most place where it applies, the masking is made redundant
and is thus eliminated
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
-rw-r--r-- | simplify.c | 14 |
1 files changed, 14 insertions, 0 deletions
@@ -1392,6 +1392,20 @@ static int simplify_compare_constant(struct instruction *insn, long long value) break; } break; + case OP_TRUNC: + osize = def->orig_type->bit_size; + switch (insn->opcode) { + case OP_SET_EQ: case OP_SET_NE: + if (one_use(def->target)) { + insn->itype = def->orig_type; + def->type = def->orig_type; + def->size = osize; + def->src2 = value_pseudo(bits); + return replace_opcode(def, OP_AND); + } + break; + } + break; case OP_ZEXT: osize = def->orig_type->bit_size; bits = bits_mask(osize); |