[Mesa-dev] [PATCH 3/3] freedreno/ir3: do idiv lowering after main opt loop

[Rob Clark]

From: Rob Clark <robclark at freedesktop.org>

Give algebraic-opt pass a chance to catch udiv by const power-of-two,
before running lower-idiv pass.

Signed-off-by: Rob Clark <robclark at freedesktop.org>
---
 src/gallium/drivers/freedreno/ir3/ir3_nir.c | 43 ++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/src/gallium/drivers/freedreno/ir3/ir3_nir.c b/src/gallium/drivers/freedreno/ir3/ir3_nir.c
index 7e3ccc0..6784987 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_nir.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_nir.c
@@ -77,6 +77,27 @@ ir3_key_lowers_nir(const struct ir3_shader_key *key)
 
 #define OPT_V(nir, pass, ...) NIR_PASS_V(nir, pass, ##__VA_ARGS__)
 
+static void
+ir3_optimize_loop(nir_shader *s)
+{
+	bool progress;
+	do {
+		progress = false;
+
+		OPT_V(s, nir_lower_vars_to_ssa);
+		OPT_V(s, nir_lower_alu_to_scalar);
+		OPT_V(s, nir_lower_phis_to_scalar);
+
+		progress |= OPT(s, nir_copy_prop);
+		progress |= OPT(s, nir_opt_dce);
+		progress |= OPT(s, nir_opt_cse);
+		progress |= OPT(s, ir3_nir_lower_if_else);
+		progress |= OPT(s, nir_opt_algebraic);
+		progress |= OPT(s, nir_opt_constant_folding);
+
+	} while (progress);
+}
+
 struct nir_shader *
 ir3_optimize_nir(struct ir3_shader *shader, nir_shader *s,
 		const struct ir3_shader_key *key)
@@ -84,7 +105,6 @@ ir3_optimize_nir(struct ir3_shader *shader, nir_shader *s,
 	struct nir_lower_tex_options tex_options = {
 			.lower_rect = 0,
 	};
-	bool progress;
 
 	if (key) {
 		switch (shader->type) {
@@ -140,24 +160,15 @@ ir3_optimize_nir(struct ir3_shader *shader, nir_shader *s,
 	}
 
 	OPT_V(s, nir_lower_tex, &tex_options);
-	OPT_V(s, nir_lower_idiv);
 	OPT_V(s, nir_lower_load_const_to_scalar);
 
-	do {
-		progress = false;
-
-		OPT_V(s, nir_lower_vars_to_ssa);
-		OPT_V(s, nir_lower_alu_to_scalar);
-		OPT_V(s, nir_lower_phis_to_scalar);
+	ir3_optimize_loop(s);
 
-		progress |= OPT(s, nir_copy_prop);
-		progress |= OPT(s, nir_opt_dce);
-		progress |= OPT(s, nir_opt_cse);
-		progress |= OPT(s, ir3_nir_lower_if_else);
-		progress |= OPT(s, nir_opt_algebraic);
-		progress |= OPT(s, nir_opt_constant_folding);
-
-	} while (progress);
+	/* do idiv lowering after first opt loop to give a chance for
+	 * divide by immed power-of-two to be caught first:
+	 */
+	if (OPT(s, nir_lower_idiv))
+		ir3_optimize_loop(s);
 
 	OPT_V(s, nir_remove_dead_variables, nir_var_local);
 
-- 
2.5.5