aco/optimizer: fix incorrect operand order assumption for neg(mul) opt

The code that labels instructions doesn't care about the order either.

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/14013
Cc: mesa-stable

Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37643>

src/amd/compiler/aco_optimizer.cpp

@@ -3757,7 +3757,7 @@ combine_instruction(opt_ctx& ctx, aco_ptr<Instruction>& instr)
 
    /* neg(mul(a, b)) -> mul(neg(a), b), abs(mul(a, b)) -> mul(abs(a), abs(b)) */
    if ((ctx.info[instr->definitions[0].tempId()].label & (label_neg | label_abs)) &&
-       ctx.uses[instr->operands[1].tempId()] == 1) {
+       ctx.uses[ctx.info[instr->definitions[0].tempId()].temp.id()] == 1) {
       Temp val = ctx.info[instr->definitions[0].tempId()].temp;
       Instruction* mul_instr = ctx.info[val.id()].parent_instr;