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authorJason Ekstrand <[email protected]>2019-06-20 11:12:54 -0500
committerJason Ekstrand <[email protected]>2019-07-10 00:20:59 +0000
commit8f7405ed9d473c1729d48c5add4f0d9fe147c75a (patch)
tree7403e2a252fe6208c06673a6cd27d7eec4bd70e6
parent9a3cb6f5fec040dea4a229b93f789995b36f9c09 (diff)
nir: Add some helpers for chasing SSA values properly
There are various cases in which we want to chase SSA values through ALU ops ranging from hand-written optimizations to back-end translation code. In all these cases, it can be very tricky to do properly because of swizzles. This set of helpers lets you easily work with a single component of an SSA def and chase through ALU ops safely. Reviewed-by: Timothy Arceri <[email protected]>
-rw-r--r--src/compiler/nir/nir.h80
1 files changed, 80 insertions, 0 deletions
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 3d50c89bf0b..4fa50940e17 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2002,6 +2002,86 @@ NIR_DEFINE_SRC_AS_CONST(double, float)
#undef NIR_DEFINE_SRC_AS_CONST
+typedef struct {
+ nir_ssa_def *def;
+ unsigned comp;
+} nir_ssa_scalar;
+
+static inline bool
+nir_ssa_scalar_is_const(nir_ssa_scalar s)
+{
+ return s.def->parent_instr->type == nir_instr_type_load_const;
+}
+
+static inline nir_const_value
+nir_ssa_scalar_as_const_value(nir_ssa_scalar s)
+{
+ assert(s.comp < s.def->num_components);
+ nir_load_const_instr *load = nir_instr_as_load_const(s.def->parent_instr);
+ return load->value[s.comp];
+}
+
+#define NIR_DEFINE_SCALAR_AS_CONST(type, suffix) \
+static inline type \
+nir_ssa_scalar_as_##suffix(nir_ssa_scalar s) \
+{ \
+ return nir_const_value_as_##suffix( \
+ nir_ssa_scalar_as_const_value(s), s.def->bit_size); \
+}
+
+NIR_DEFINE_SCALAR_AS_CONST(int64_t, int)
+NIR_DEFINE_SCALAR_AS_CONST(uint64_t, uint)
+NIR_DEFINE_SCALAR_AS_CONST(bool, bool)
+NIR_DEFINE_SCALAR_AS_CONST(double, float)
+
+#undef NIR_DEFINE_SCALAR_AS_CONST
+
+static inline bool
+nir_ssa_scalar_is_alu(nir_ssa_scalar s)
+{
+ return s.def->parent_instr->type == nir_instr_type_alu;
+}
+
+static inline nir_op
+nir_ssa_scalar_alu_op(nir_ssa_scalar s)
+{
+ return nir_instr_as_alu(s.def->parent_instr)->op;
+}
+
+static inline nir_ssa_scalar
+nir_ssa_scalar_chase_alu_src(nir_ssa_scalar s, unsigned alu_src_idx)
+{
+ nir_ssa_scalar out = { NULL, 0 };
+
+ nir_alu_instr *alu = nir_instr_as_alu(s.def->parent_instr);
+ assert(alu_src_idx < nir_op_infos[alu->op].num_inputs);
+
+ /* Our component must be written */
+ assert(s.comp < s.def->num_components);
+ assert(alu->dest.write_mask & (1u << s.comp));
+
+ assert(alu->src[alu_src_idx].src.is_ssa);
+ out.def = alu->src[alu_src_idx].src.ssa;
+
+ if (nir_op_infos[alu->op].input_sizes[alu_src_idx] == 0) {
+ /* The ALU src is unsized so the source component follows the
+ * destination component.
+ */
+ out.comp = alu->src[alu_src_idx].swizzle[s.comp];
+ } else {
+ /* This is a sized source so all source components work together to
+ * produce all the destination components. Since we need to return a
+ * scalar, this only works if the source is a scalar.
+ */
+ assert(nir_op_infos[alu->op].input_sizes[alu_src_idx] == 1);
+ out.comp = alu->src[alu_src_idx].swizzle[0];
+ }
+ assert(out.comp < out.def->num_components);
+
+ return out;
+}
+
+
/*
* Control flow
*