Mesa (master): pan/bi: Interpret register allocation results
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Thu Mar 12 12:53:27 UTC 2020
Module: Mesa
Branch: master
Commit: dcc50f4302d9904e5c433d8bd81af6fcb3159479
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=dcc50f4302d9904e5c433d8bd81af6fcb3159479
Author: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Date: Thu Mar 12 08:05:58 2020 -0400
pan/bi: Interpret register allocation results
Once LCRA has run, we have a map from IR indices to byte offsets into
the register file, so we need to "install" these results, rewriting the
IR to use native registers and fixing up writemasks/swizzles to
substitute vectorization for adjacent registers (for LCRA, we're
modeling in terms of real vectors).
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4158>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4158>
---
src/panfrost/bifrost/bi_ra.c | 95 ++++++++++++++++++++++++++++++++++
src/panfrost/bifrost/bifrost_compile.c | 1 +
2 files changed, 96 insertions(+)
diff --git a/src/panfrost/bifrost/bi_ra.c b/src/panfrost/bifrost/bi_ra.c
index b30f0e7aceb..8c0fa92a12e 100644
--- a/src/panfrost/bifrost/bi_ra.c
+++ b/src/panfrost/bifrost/bi_ra.c
@@ -89,6 +89,99 @@ bi_allocate_registers(bi_context *ctx, bool *success)
return l;
}
+static unsigned
+bi_reg_from_index(struct lcra_state *l, unsigned index, unsigned offset)
+{
+ /* Did we run RA for this index at all */
+ if (index >= l->node_count)
+ return index;
+
+ /* LCRA didn't bother solving this index (how lazy!) */
+ signed solution = l->solutions[index];
+ if (solution < 0)
+ return index;
+
+ solution += offset;
+
+ assert((solution & 0x3) == 0);
+ unsigned reg = solution / 4;
+ return BIR_INDEX_REGISTER | reg;
+}
+
+static void
+bi_adjust_src_ra(bi_instruction *ins, struct lcra_state *l, unsigned src)
+{
+ if (ins->src[src] >= l->node_count)
+ return;
+
+ bool vector = (bi_class_props[ins->type] & BI_VECTOR);
+ unsigned offset = 0;
+
+ if (vector) {
+ /* TODO: Do we do anything here? */
+ } else {
+ /* Use the swizzle as component select */
+ nir_alu_type T = ins->src_types[src];
+ unsigned size = nir_alu_type_get_type_size(T);
+ unsigned bytes = (MAX2(size, 8) / 8);
+ unsigned comps_per_reg = 4 / bytes;
+ unsigned components = bi_get_component_count(ins);
+
+ for (unsigned i = 0; i < components; ++i) {
+ unsigned off = ins->swizzle[src][i] / comps_per_reg;
+ off *= 4; /* 32-bit registers */
+
+ /* We can't cross register boundaries in a swizzle */
+ if (i == 0)
+ offset = off;
+ else
+ assert(off == offset);
+
+ ins->swizzle[src][i] %= comps_per_reg;
+ }
+ }
+
+ ins->src[src] = bi_reg_from_index(l, ins->src[src], offset);
+}
+
+static void
+bi_adjust_dest_ra(bi_instruction *ins, struct lcra_state *l)
+{
+ if (ins->dest >= l->node_count)
+ return;
+
+ bool vector = (bi_class_props[ins->type] & BI_VECTOR);
+ unsigned offset = 0;
+
+ if (!vector) {
+ /* Look at the writemask to get an offset, specifically the
+ * trailing zeros */
+
+ unsigned tz = __builtin_ctz(ins->writemask);
+
+ /* Recall writemask is one bit per byte, so tz is in bytes */
+ unsigned regs = tz / 4;
+ offset = regs * 4;
+
+ /* Adjust writemask to compensate */
+ ins->writemask >>= offset;
+ }
+
+ ins->dest = bi_reg_from_index(l, ins->dest, offset);
+
+}
+
+static void
+bi_install_registers(bi_context *ctx, struct lcra_state *l)
+{
+ bi_foreach_instr_global(ctx, ins) {
+ bi_adjust_dest_ra(ins, l);
+
+ bi_foreach_src(ins, s)
+ bi_adjust_src_ra(ins, l, s);
+ }
+}
+
void
bi_register_allocate(bi_context *ctx)
{
@@ -108,5 +201,7 @@ bi_register_allocate(bi_context *ctx)
assert(success);
} while(!success);
+ bi_install_registers(ctx, l);
+
lcra_free(l);
}
diff --git a/src/panfrost/bifrost/bifrost_compile.c b/src/panfrost/bifrost/bifrost_compile.c
index b9cb89d961b..f25f7424409 100644
--- a/src/panfrost/bifrost/bifrost_compile.c
+++ b/src/panfrost/bifrost/bifrost_compile.c
@@ -864,6 +864,7 @@ bifrost_compile_shader_nir(nir_shader *nir, panfrost_program *program, unsigned
bi_print_shader(ctx, stdout);
bi_schedule(ctx);
bi_register_allocate(ctx);
+ bi_print_shader(ctx, stdout);
ralloc_free(ctx);
}
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