diff --git a/src/amd/compiler/aco_optimizer_postRA.cpp b/src/amd/compiler/aco_optimizer_postRA.cpp
index 510b9e196da..6435a54ef4e 100644
--- a/src/amd/compiler/aco_optimizer_postRA.cpp
+++ b/src/amd/compiler/aco_optimizer_postRA.cpp
@@ -109,13 +109,13 @@ struct pr_opt_ctx {
          std::fill(instr_idx_by_regs[block->index].begin(), instr_idx_by_regs[block->index].end(),
                    not_written_yet);
       } else if (block->kind & block_kind_loop_header) {
-         /* Initialize with content from loop preheader */
-         memcpy(&instr_idx_by_regs[block->index][0], &instr_idx_by_regs[block->index - 1][0],
-                max_reg_cnt * sizeof(Idx));
-
-         /* Assume exec writes on back-edges */
-         instr_idx_by_regs[block->index][126] = overwritten_untrackable;
-         instr_idx_by_regs[block->index][127] = overwritten_untrackable;
+         /* Instructions inside the loop may overwrite registers of temporaries that are
+          * not live inside the loop, but we can't detect that because we haven't processed
+          * the blocks in the loop yet. As a workaround, mark all registers as untrackable.
+          * TODO: Consider improving this in the future.
+          */
+         std::fill(instr_idx_by_regs[block->index].begin(), instr_idx_by_regs[block->index].end(),
+                   overwritten_untrackable);
       } else {
          reset_block_regs(block->linear_preds, block->index, 0, max_sgpr_cnt);
          reset_block_regs(block->linear_preds, block->index, 251, 3);