aco: combine more s_add+s_lshl to s_lshl<n>_add by ignoring uses

Even if the s_lshl is used more that once, it can still be combined.

fossils-db (Vega10):
Totals from 771 (0.55% of 139517) affected shaders:
SGPRs: 46216 -> 46304 (+0.19%); split: -0.02%, +0.21%
VGPRs: 38488 -> 38464 (-0.06%)
SpillSGPRs: 1894 -> 1875 (-1.00%); split: -3.12%, +2.11%
CodeSize: 5681856 -> 5679844 (-0.04%); split: -0.07%, +0.03%
MaxWaves: 5320 -> 5323 (+0.06%)
Instrs: 1093960 -> 1093474 (-0.04%); split: -0.09%, +0.05%
Cycles: 47198380 -> 47258872 (+0.13%); split: -0.06%, +0.19%
VMEM: 176036 -> 176283 (+0.14%); split: +0.16%, -0.02%
SMEM: 53397 -> 53255 (-0.27%); split: +0.03%, -0.30%
VClause: 23156 -> 23152 (-0.02%); split: -0.03%, +0.01%
SClause: 35716 -> 35726 (+0.03%); split: -0.00%, +0.03%
Copies: 139395 -> 139871 (+0.34%); split: -0.04%, +0.39%
Branches: 33808 -> 33798 (-0.03%); split: -0.04%, +0.01%
PreSGPRs: 35381 -> 35331 (-0.14%); split: -0.20%, +0.06%

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7539>

diff --git a/src/amd/compiler/aco_optimizer.cpp b/src/amd/compiler/aco_optimizer.cpp
index 9d62190..89fcdee 100644 (file)
--- a/src/amd/compiler/aco_optimizer.cpp
+++ b/src/amd/compiler/aco_optimizer.cpp
@@ -2207,7 +2207,7 @@ bool combine_salu_lshl_add(opt_ctx& ctx, aco_ptr<Instruction>& instr)
       return false;
 
    for (unsigned i = 0; i < 2; i++) {
-      Instruction *op2_instr = follow_operand(ctx, instr->operands[i]);
+      Instruction *op2_instr = follow_operand(ctx, instr->operands[i], true);
       if (!op2_instr || op2_instr->opcode != aco_opcode::s_lshl_b32 ||
           ctx.uses[op2_instr->definitions[1].tempId()])
          continue;

diff --git a/src/amd/compiler/tests/test_optimizer.cpp b/src/amd/compiler/tests/test_optimizer.cpp
index 00e4cde..4be2f62 100644 (file)
--- a/src/amd/compiler/tests/test_optimizer.cpp
+++ b/src/amd/compiler/tests/test_optimizer.cpp
@@ -143,9 +143,9 @@ BEGIN_TEST(optimize.add_lshl)
                        Operand(inputs[0]), Operand(3u));
       writeout(0, bld.sop2(aco_opcode::s_add_u32, bld.def(s1), bld.def(s1, scc), shift, Operand(4u)));
 
-      //! s1: %lshl, s1: %_:scc = s_lshl_b32 %a, 3
-      //! v1: %add = v_add_u32 %lshl, %b
-      //! v1: %res1 = v_add3_u32 %add, %lshl, 4
+      //! s1: %lshl1, s1: %_:scc = s_lshl3_add_u32 %a, 4
+      //! v1: %lshl_add = v_lshl_add_u32 %a, 3, %b
+      //! v1: %res1 = v_add_u32 %lshl1, %lshl_add
       //! p_unit_test 1, %res1
       shift = bld.sop2(aco_opcode::s_lshl_b32, bld.def(s1), bld.def(s1, scc),
                        Operand(inputs[0]), Operand(3u));