agx: Implement simple copyprop

Cleans up some of the mess.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16268>

src/asahi/compiler/agx_optimizer.c

@@ -151,6 +151,29 @@ agx_optimizer_fmov_rev(agx_instr *I, agx_instr *use)
    return true;
 }
 
+static void
+agx_optimizer_copyprop(agx_instr **defs, agx_instr *I, unsigned srcs)
+{
+   for (unsigned s = 0; s < srcs; ++s) {
+      agx_index src = I->src[s];
+      if (src.type != AGX_INDEX_NORMAL) continue;
+
+      agx_instr *def = defs[src.value];
+      if (def->op != AGX_OPCODE_MOV) continue;
+
+      /* At the moment, not all instructions support size conversions. Notably
+       * RA pseudo instructions don't handle size conversions. This should be
+       * refined in the future.
+       */
+      if (def->src[0].size != src.size) continue;
+
+      /* Immediate inlining happens elsewhere */
+      if (def->src[0].type == AGX_INDEX_IMMEDIATE) continue;
+
+      I->src[s] = agx_replace_index(src, def->src[0]);
+   }
+}
+
 static void
 agx_optimizer_forward(agx_context *ctx)
 {
@@ -164,6 +187,9 @@ agx_optimizer_forward(agx_context *ctx)
             defs[I->dest[d].value] = I;
       }
 
+      /* Optimize moves */
+      agx_optimizer_copyprop(defs, I, info.nr_srcs);
+
       /* Propagate fmov down */
       if (info.is_float)
          agx_optimizer_fmov(defs, I, info.nr_srcs);

src/asahi/compiler/test/test-optimizer.cpp

@@ -72,3 +72,41 @@ TEST_F(Optimizer, FusedFABSNEG)
    CASE(agx_fmul_to(b, wz, wx, agx_fmov(b, agx_neg(agx_abs(wx)))),
         agx_fmul_to(b, wz, wx, agx_neg(agx_abs(wx))));
 }
+
+TEST_F(Optimizer, Copyprop)
+{
+   CASE(agx_fmul_to(b, wz, wx, agx_mov(b, wy)), agx_fmul_to(b, wz, wx, wy));
+   CASE(agx_fmul_to(b, wz, agx_mov(b, wx), agx_mov(b, wy)), agx_fmul_to(b, wz, wx, wy));
+}
+
+TEST_F(Optimizer, InlineHazards)
+{
+   NEGCASE(agx_p_combine_to(b, wx, agx_mov_imm(b, AGX_SIZE_32, 0), wy, wz, wz));
+}
+
+TEST_F(Optimizer, CopypropRespectsAbsNeg)
+{
+   CASE(agx_fadd_to(b, wz, agx_abs(agx_mov(b, wx)), wy),
+        agx_fadd_to(b, wz, agx_abs(wx), wy));
+
+   CASE(agx_fadd_to(b, wz, agx_neg(agx_mov(b, wx)), wy),
+        agx_fadd_to(b, wz, agx_neg(wx), wy));
+
+   CASE(agx_fadd_to(b, wz, agx_neg(agx_abs(agx_mov(b, wx))), wy),
+        agx_fadd_to(b, wz, agx_neg(agx_abs(wx)), wy));
+}
+
+TEST_F(Optimizer, IntCopyprop)
+{
+   CASE(agx_xor_to(b, wz, agx_mov(b, wx), wy),
+        agx_xor_to(b, wz, wx, wy));
+}
+
+TEST_F(Optimizer, IntCopypropDoesntConvert)
+{
+   NEGCASE({
+         agx_index cvt = agx_temp(b->shader, AGX_SIZE_32);
+         agx_mov_to(b, cvt, hx);
+         agx_xor_to(b, wz, cvt, wy);
+   });
+}