freedreno/ir3/cf: handle multiple cov's properly

There can be multiple (for ex.) f32f16's from a single source, in
particular appearing in different blocks.  We need to update all uses
of the src which had conversion folded in, not all the uses of the
individual cov.  Also, to avoid invalidating the ssa use info that was
gathered at the beginning of the pass, don't actually eliminate the
cov, but instead change it to a simple mov that the cp pass can gobble
up.

Signed-off-by: Rob Clark <[email protected]>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5048>

1 files changed, 19 insertions, 8 deletions

diff --git a/src/freedreno/ir3/ir3_cf.c b/src/freedreno/ir3/ir3_cf.c
index ee717187a99..c1dc5385d36 100644
--- a/src/freedreno/ir3/ir3_cf.c
+++ b/src/freedreno/ir3/ir3_cf.c
@@ -65,14 +65,24 @@ all_uses_fp16_conv(struct ir3_instruction *conv_src)
 	return true;
 }
 
+/* For an instruction which has a conversion folded in, re-write the
+ * uses of *all* conv's that used that src to be a simple mov that
+ * cp can eliminate.  This avoids invalidating the SSA uses, it just
+ * shifts the use to a simple mov.
+ */
 static void
-rewrite_uses(struct ir3_instruction *conv, struct ir3_instruction *replace)
+rewrite_src_uses(struct ir3_instruction *src)
 {
-	foreach_ssa_use (use, conv) {
-		foreach_ssa_src_n (src, n, use) {
-			if (src == conv)
-				use->regs[n]->instr = replace;
+	foreach_ssa_use (use, src) {
+		assert(is_fp16_conv(use));
+
+		if (is_half(src)) {
+			use->regs[1]->flags |= IR3_REG_HALF;
+		} else {
+			use->regs[1]->flags &= ~IR3_REG_HALF;
 		}
+
+		use->cat1.src_type = use->cat1.dst_type;
 	}
 }
 
@@ -113,6 +123,7 @@ try_conversion_folding(struct ir3_instruction *conv)
 		if (src->cat1.dst_type != src->cat1.src_type &&
 			conv->cat1.src_type != src->cat1.dst_type)
 			return false;
+		break;
 	default:
 		break;
 	}
@@ -137,13 +148,13 @@ try_conversion_folding(struct ir3_instruction *conv)
 		}
 	}
 
-	if (conv->regs[0]->flags & IR3_REG_HALF) {
+	if (is_half(conv)) {
 		src->regs[0]->flags |= IR3_REG_HALF;
 	} else {
 		src->regs[0]->flags &= ~IR3_REG_HALF;
 	}
 
-	rewrite_uses(conv, src);
+	rewrite_src_uses(src);
 
 	return true;
 }
@@ -157,7 +168,7 @@ ir3_cf(struct ir3 *ir)
 	ir3_find_ssa_uses(ir, mem_ctx, false);
 
 	foreach_block (block, &ir->block_list) {
-		foreach_instr_safe (instr, &block->instr_list) {
+		foreach_instr (instr, &block->instr_list) {
 			progress |= try_conversion_folding(instr);
 		}
 	}