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authorJason Ekstrand <jason.ekstrand@intel.com>2016-03-17 11:38:54 -0700
committerJason Ekstrand <jason.ekstrand@intel.com>2016-03-23 16:28:06 -0700
commit5f39e3e16510b840f53ef6172631cca8a9f0eaeb (patch)
treee823ad365a6ea08a20bb61b874f2184f4962f73d
parent0dbda153aae548a4087f7364c9013583a076e0e9 (diff)
downloadmesa-5f39e3e16510b840f53ef6172631cca8a9f0eaeb.tar.gz
nir/cse: Properly handle nir_ssa_def.exact
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
-rw-r--r--src/compiler/nir/nir_instr_set.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/src/compiler/nir/nir_instr_set.c b/src/compiler/nir/nir_instr_set.c
index 3f5da496092..e244122e466 100644
--- a/src/compiler/nir/nir_instr_set.c
+++ b/src/compiler/nir/nir_instr_set.c
@@ -52,6 +52,7 @@ hash_alu(uint32_t hash, const nir_alu_instr *instr)
{
hash = HASH(hash, instr->op);
hash = HASH(hash, instr->dest.dest.ssa.num_components);
+ /* We explicitly don't hash instr->dest.dest.exact */
if (nir_op_infos[instr->op].algebraic_properties & NIR_OP_IS_COMMUTATIVE) {
assert(nir_op_infos[instr->op].num_inputs == 2);
@@ -267,6 +268,8 @@ nir_instrs_equal(const nir_instr *instr1, const nir_instr *instr2)
if (alu1->dest.dest.ssa.num_components != alu2->dest.dest.ssa.num_components)
return false;
+ /* We explicitly don't hash instr->dest.dest.exact */
+
if (nir_op_infos[alu1->op].algebraic_properties & NIR_OP_IS_COMMUTATIVE) {
assert(nir_op_infos[alu1->op].num_inputs == 2);
return (nir_alu_srcs_equal(alu1, alu2, 0, 0) &&
@@ -496,8 +499,17 @@ nir_instr_set_add_or_rewrite(struct set *instr_set, nir_instr *instr)
struct set_entry *entry = _mesa_set_search(instr_set, instr);
if (entry) {
nir_ssa_def *def = nir_instr_get_dest_ssa_def(instr);
- nir_ssa_def *new_def =
- nir_instr_get_dest_ssa_def((nir_instr *) entry->key);
+ nir_instr *match = (nir_instr *) entry->key;
+ nir_ssa_def *new_def = nir_instr_get_dest_ssa_def(match);
+
+ /* It's safe to replace a exact instruction with an inexact one as
+ * long as we make it exact. If we got here, the two instructions are
+ * exactly identical in every other way so, once we've set the exact
+ * bit, they are the same.
+ */
+ if (instr->type == nir_instr_type_alu && nir_instr_as_alu(instr)->exact)
+ nir_instr_as_alu(match)->exact = true;
+
nir_ssa_def_rewrite_uses(def, nir_src_for_ssa(new_def));
return true;
}