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authorJason Ekstrand <[email protected]>2015-11-12 08:40:17 -0800
committerJason Ekstrand <[email protected]>2015-11-23 11:04:49 -0800
commit7e83fd85aa9e448aa588b3e981fdc8e026dd51b9 (patch)
tree986547ee7ac3a26d4ca20affbcd1fd04c4a5376c /src/glsl/nir
parent384396a69bdfec9971337863ae69266c7fa4a2e8 (diff)
nir: Add a ssa_def_rewrite_uses_after helper
Reviewed-by: Connor Abbott <[email protected]>
Diffstat (limited to 'src/glsl/nir')
-rw-r--r--src/glsl/nir/nir.c49
-rw-r--r--src/glsl/nir/nir.h2
2 files changed, 51 insertions, 0 deletions
diff --git a/src/glsl/nir/nir.c b/src/glsl/nir/nir.c
index 470469429dd..bfec11e53ff 100644
--- a/src/glsl/nir/nir.c
+++ b/src/glsl/nir/nir.c
@@ -1319,6 +1319,55 @@ nir_ssa_def_rewrite_uses(nir_ssa_def *def, nir_src new_src)
nir_if_rewrite_condition(use_src->parent_if, new_src);
}
+static bool
+is_instr_between(nir_instr *start, nir_instr *end, nir_instr *between)
+{
+ assert(start->block == end->block);
+
+ if (between->block != start->block)
+ return false;
+
+ /* Search backwards looking for "between" */
+ while (start != end) {
+ if (between == end)
+ return true;
+
+ end = nir_instr_prev(end);
+ assert(end);
+ }
+
+ return false;
+}
+
+/* Replaces all uses of the given SSA def with the given source but only if
+ * the use comes after the after_me instruction. This can be useful if you
+ * are emitting code to fix up the result of some instruction: you can freely
+ * use the result in that code and then call rewrite_uses_after and pass the
+ * last fixup instruction as after_me and it will replace all of the uses you
+ * want without touching the fixup code.
+ *
+ * This function assumes that after_me is in the same block as
+ * def->parent_instr and that after_me comes after def->parent_instr.
+ */
+void
+nir_ssa_def_rewrite_uses_after(nir_ssa_def *def, nir_src new_src,
+ nir_instr *after_me)
+{
+ assert(!new_src.is_ssa || def != new_src.ssa);
+
+ nir_foreach_use_safe(def, use_src) {
+ assert(use_src->parent_instr != def->parent_instr);
+ /* Since def already dominates all of its uses, the only way a use can
+ * not be dominated by after_me is if it is between def and after_me in
+ * the instruction list.
+ */
+ if (!is_instr_between(def->parent_instr, after_me, use_src->parent_instr))
+ nir_instr_rewrite_src(use_src->parent_instr, use_src, new_src);
+ }
+
+ nir_foreach_if_use_safe(def, use_src)
+ nir_if_rewrite_condition(use_src->parent_if, new_src);
+}
static bool foreach_cf_node(nir_cf_node *node, nir_foreach_block_cb cb,
bool reverse, void *state);
diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
index 28c85459021..2bdfcb80faf 100644
--- a/src/glsl/nir/nir.h
+++ b/src/glsl/nir/nir.h
@@ -1868,6 +1868,8 @@ void nir_ssa_dest_init(nir_instr *instr, nir_dest *dest,
void nir_ssa_def_init(nir_instr *instr, nir_ssa_def *def,
unsigned num_components, const char *name);
void nir_ssa_def_rewrite_uses(nir_ssa_def *def, nir_src new_src);
+void nir_ssa_def_rewrite_uses_after(nir_ssa_def *def, nir_src new_src,
+ nir_instr *after_me);
/* visits basic blocks in source-code order */
typedef bool (*nir_foreach_block_cb)(nir_block *block, void *state);