--- /dev/null
+/*
+ * Copyright (C) 2022 Alyssa Rosenzweig <alyssa@rosenzweig.io>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "agx_compiler.h"
+#include "agx_builder.h"
+
+/*
+ * Lower 64-bit moves to 32-bit moves. Although there are not 64-bit moves in
+ * the ISA, it is convenient to pretend there are for instruction selection.
+ * They are lowered trivially after register allocation.
+ *
+ * General 64-bit lowering happens in nir_lower_int64.
+ */
+static bool
+lower(agx_builder *b, agx_instr *I)
+{
+ if (I->op != AGX_OPCODE_MOV && I->op != AGX_OPCODE_MOV_IMM)
+ return false;
+
+ if (I->dest[0].size != AGX_SIZE_64)
+ return false;
+
+ agx_index dest = I->dest[0];
+ dest.size = AGX_SIZE_32;
+
+ if (I->op == AGX_OPCODE_MOV) {
+ assert(I->src[0].type == AGX_INDEX_REGISTER ||
+ I->src[0].type == AGX_INDEX_UNIFORM);
+ assert(I->src[0].size == AGX_SIZE_64);
+ agx_index src = I->src[0];
+ src.size = AGX_SIZE_32;
+
+ /* Low 32-bit */
+ agx_mov_to(b, dest, src);
+
+ /* High 32-bits */
+ dest.value += 2;
+ src.value += 2;
+ agx_mov_to(b, dest, src);
+ } else {
+ /* Low 32-bit */
+ agx_mov_imm_to(b, dest, I->imm & BITFIELD_MASK(32));
+
+ /* High 32-bits */
+ dest.value += 2;
+ agx_mov_imm_to(b, dest, I->imm >> 32);
+ }
+
+ return true;
+}
+
+void
+agx_lower_64bit_postra(agx_context *ctx)
+{
+ agx_foreach_instr_global_safe(ctx, I) {
+ agx_builder b = agx_init_builder(ctx, agx_before_instr(I));
+
+ if (lower(&b, I))
+ agx_remove_instruction(I);
+ }
+}