diff --git a/src/gallium/auxiliary/gallivm/lp_bld_nir.c b/src/gallium/auxiliary/gallivm/lp_bld_nir.c
index 8db40661231..3669e6e6fc1 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_nir.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_nir.c
@@ -1021,7 +1021,7 @@ static void visit_alu(struct lp_build_nir_context *bld_base, const nir_alu_instr
          result[i] = cast_type(bld_base, src[i], nir_op_infos[instr->op].input_types[i], src_bit_size[i]);
       }
    } else if (instr->op == nir_op_fsum4 || instr->op == nir_op_fsum3 || instr->op == nir_op_fsum2) {
-      for (unsigned c = 0; c < nir_src_num_components(instr->src[0].src); c++) {
+      for (unsigned c = 0; c < nir_op_infos[instr->op].input_sizes[0]; c++) {
          LLVMValueRef temp_chan = LLVMBuildExtractValue(gallivm->builder,
                                                           src[0], c, "");
          temp_chan = cast_type(bld_base, temp_chan, nir_op_infos[instr->op].input_types[0], src_bit_size[0]);