Mesa (master): aco: disable some instruction combining if it could change an exec operand

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Module: Mesa
Branch: master
Commit: d45e9451cf47014d37816baf2656981a1c715e50
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=d45e9451cf47014d37816baf2656981a1c715e50

Author: Rhys Perry <pendingchaos02 at gmail.com>
Date:   Tue Jan 28 12:04:48 2020 +0000

aco: disable some instruction combining if it could change an exec operand

Found by observation. No pipeline-db changes.

Signed-off-by: Rhys Perry <pendingchaos02 at gmail.com>
Reviewed-by: Daniel Schürmann <daniel at schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3599>

---

 src/amd/compiler/aco_optimizer.cpp | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/amd/compiler/aco_optimizer.cpp b/src/amd/compiler/aco_optimizer.cpp
index 5f2e5637b71..c729cbc68f4 100644
--- a/src/amd/compiler/aco_optimizer.cpp
+++ b/src/amd/compiler/aco_optimizer.cpp
@@ -665,6 +665,11 @@ Operand get_constant_op(opt_ctx &ctx, uint32_t val, bool is64bit = false)
    return op;
 }
 
+bool fixed_to_exec(Operand op)
+{
+   return op.isFixed() && op.physReg() == exec;
+}
+
 void label_instruction(opt_ctx &ctx, Block& block, aco_ptr<Instruction>& instr)
 {
    if (instr->isSALU() || instr->isVALU() || instr->format == Format::PSEUDO) {
@@ -1155,7 +1160,7 @@ void label_instruction(opt_ctx &ctx, Block& block, aco_ptr<Instruction>& instr)
       break;
    case aco_opcode::s_and_b32:
    case aco_opcode::s_and_b64:
-      if (instr->operands[1].isFixed() && instr->operands[1].physReg() == exec && instr->operands[0].isTemp()) {
+      if (fixed_to_exec(instr->operands[1]) && instr->operands[0].isTemp()) {
          if (ctx.info[instr->operands[0].tempId()].is_uniform_bool()) {
             /* Try to get rid of the superfluous s_cselect + s_and_b64 that comes from turning a uniform bool into divergent */
             ctx.info[instr->definitions[1].tempId()].set_temp(ctx.info[instr->operands[0].tempId()].temp);
@@ -1640,6 +1645,8 @@ bool match_op3_for_vop3(opt_ctx &ctx, aco_opcode op1, aco_opcode op2,
    Instruction *op2_instr = follow_operand(ctx, op1_instr->operands[swap]);
    if (!op2_instr || op2_instr->opcode != op2)
       return false;
+   if (fixed_to_exec(op2_instr->operands[0]) || fixed_to_exec(op2_instr->operands[1]))
+      return false;
 
    VOP3A_instruction *op1_vop3 = op1_instr->isVOP3() ? static_cast<VOP3A_instruction *>(op1_instr) : NULL;
    VOP3A_instruction *op2_vop3 = op2_instr->isVOP3() ? static_cast<VOP3A_instruction *>(op2_instr) : NULL;
@@ -1851,6 +1858,8 @@ bool combine_salu_n2(opt_ctx& ctx, aco_ptr<Instruction>& instr)
       Instruction *op2_instr = follow_operand(ctx, instr->operands[i]);
       if (!op2_instr || (op2_instr->opcode != aco_opcode::s_not_b32 && op2_instr->opcode != aco_opcode::s_not_b64))
          continue;
+      if (fixed_to_exec(op2_instr->operands[0]))
+         continue;
 
       if (instr->operands[!i].isLiteral() && op2_instr->operands[0].isLiteral() &&
           instr->operands[!i].constantValue() != op2_instr->operands[0].constantValue())
@@ -1891,7 +1900,9 @@ bool combine_salu_lshl_add(opt_ctx& ctx, aco_ptr<Instruction>& instr)
 
    for (unsigned i = 0; i < 2; i++) {
       Instruction *op2_instr = follow_operand(ctx, instr->operands[i]);
-      if (!op2_instr || op2_instr->opcode != aco_opcode::s_lshl_b32 || !op2_instr->operands[1].isConstant())
+      if (!op2_instr || op2_instr->opcode != aco_opcode::s_lshl_b32)
+         continue;
+      if (!op2_instr->operands[1].isConstant() || fixed_to_exec(op2_instr->operands[0]))
          continue;
 
       uint32_t shift = op2_instr->operands[1].constantValue();