Mesa (master): freedreno/ir3: add a pass to collect SSA uses

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Module: Mesa
Branch: master
Commit: 72f6b03aec42dcfa7b38aa4eb1c94a0143e2aed0
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=72f6b03aec42dcfa7b38aa4eb1c94a0143e2aed0

Author: Rob Clark <robdclark at chromium.org>
Date:   Thu Mar 12 14:18:04 2020 -0700

freedreno/ir3: add a pass to collect SSA uses

We don't really track these as the ir is transformed, but it would be a
useful thing for some passes to have.  So add a pass to collect this
information.  It uses instr->data (generic per-pass ptr), with the
hashsets hanging under a mem_ctx for easy disposal at the end of the
pass.

Signed-off-by: Rob Clark <robdclark at chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4423>

---

 src/freedreno/ir3/ir3.c | 24 ++++++++++++++++++++++++
 src/freedreno/ir3/ir3.h | 13 +++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/src/freedreno/ir3/ir3.c b/src/freedreno/ir3/ir3.c
index bf842701868..4ac50aec0a3 100644
--- a/src/freedreno/ir3/ir3.c
+++ b/src/freedreno/ir3/ir3.c
@@ -1128,3 +1128,27 @@ ir3_lookup_array(struct ir3 *ir, unsigned id)
 			return arr;
 	return NULL;
 }
+
+void
+ir3_find_ssa_uses(struct ir3 *ir, void *mem_ctx)
+{
+	/* We could do this in a single pass if we can assume instructions
+	 * are always sorted.  Which currently might not always be true.
+	 * (In particular after ir3_group pass, but maybe other places.)
+	 */
+	foreach_block (block, &ir->block_list)
+		foreach_instr (instr, &block->instr_list)
+			instr->uses = NULL;
+
+	foreach_block (block, &ir->block_list) {
+		foreach_instr (instr, &block->instr_list) {
+			struct ir3_instruction *src;
+
+			foreach_ssa_src (src, instr) {
+				if (!src->uses)
+					src->uses = _mesa_pointer_set_create(mem_ctx);
+				_mesa_set_add(src->uses, instr);
+			}
+		}
+	}
+}
diff --git a/src/freedreno/ir3/ir3.h b/src/freedreno/ir3/ir3.h
index c8abd50b034..ed51189ae3d 100644
--- a/src/freedreno/ir3/ir3.h
+++ b/src/freedreno/ir3/ir3.h
@@ -325,6 +325,11 @@ struct ir3_instruction {
 	 */
 	void *data;
 
+	/**
+	 * Valid if pass calls ir3_find_ssa_uses().. see foreach_ssa_use()
+	 */
+	struct set *uses;
+
 	int sun;            /* Sethi–Ullman number, used by sched */
 	int use_count;      /* currently just updated/used by cp */
 
@@ -593,6 +598,14 @@ void ir3_clear_mark(struct ir3 *shader);
 
 unsigned ir3_count_instructions(struct ir3 *ir);
 
+void ir3_find_ssa_uses(struct ir3 *ir, void *mem_ctx);
+
+#include "util/set.h"
+#define foreach_ssa_use(__use, __instr) \
+	for (struct ir3_instruction *__use = (void *)~0; \
+	     __use && (__instr)->uses; __use = NULL) \
+		set_foreach ((__instr)->uses, __entry) \
+			if ((__use = (void *)__entry->key))
 
 #define MAX_ARRAYS 16