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aco: improve check for unreachable loop continue blocks

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The old code would have previously caught:
loop {
   ...
   break
}
when it was meant to just catch:
loop {
   if (...)
      break
   else
      break
}

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
CC: <mesa-stable@lists.freedesktop.org>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3658>
This commit is contained in:
Rhys Perry
2020-01-31 16:39:20 +00:00
committed by Marge Bot
parent 46e94fd854
commit 8d8c864beb
1 changed files with 10 additions and 6 deletions
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src/amd/compiler/aco_instruction_selection.cpp
+10 -6
View File
@@ -90,7 +90,7 @@ struct if_context {
Block BB_endif;
};
static void visit_cf_list(struct isel_context *ctx,
static bool visit_cf_list(struct isel_context *ctx,
struct exec_list *list);
static void add_logical_edge(unsigned pred_idx, Block *succ)
@@ -8566,7 +8566,7 @@ static void visit_loop(isel_context *ctx, nir_loop *loop)
unsigned loop_header_idx = loop_header->index;
loop_info_RAII loop_raii(ctx, loop_header_idx, &loop_exit);
append_logical_start(ctx->block);
visit_cf_list(ctx, &loop->body);
bool unreachable = visit_cf_list(ctx, &loop->body);
//TODO: what if a loop ends with a unconditional or uniformly branched continue and this branch is never taken?
if (!ctx->cf_info.has_branch) {
@@ -8611,8 +8611,11 @@ static void visit_loop(isel_context *ctx, nir_loop *loop)
bld.branch(aco_opcode::p_branch);
}
/* fixup phis in loop header from unreachable blocks */
if (ctx->cf_info.has_branch || ctx->cf_info.parent_loop.has_divergent_branch) {
/* Fixup phis in loop header from unreachable blocks.
* has_branch/has_divergent_branch also indicates if the loop ends with a
* break/continue instruction, but we don't emit those if unreachable=true */
if (unreachable) {
assert(ctx->cf_info.has_branch || ctx->cf_info.parent_loop.has_divergent_branch);
bool linear = ctx->cf_info.has_branch;
bool logical = ctx->cf_info.has_branch || ctx->cf_info.parent_loop.has_divergent_branch;
for (aco_ptr<Instruction>& instr : ctx->program->blocks[loop_header_idx].instructions) {
@@ -8956,7 +8959,7 @@ static bool visit_if(isel_context *ctx, nir_if *if_stmt)
}
}
static void visit_cf_list(isel_context *ctx,
static bool visit_cf_list(isel_context *ctx,
struct exec_list *list)
{
foreach_list_typed(nir_cf_node, node, node, list) {
@@ -8966,7 +8969,7 @@ static void visit_cf_list(isel_context *ctx,
break;
case nir_cf_node_if:
if (!visit_if(ctx, nir_cf_node_as_if(node)))
return;
return true;
break;
case nir_cf_node_loop:
visit_loop(ctx, nir_cf_node_as_loop(node));
@@ -8975,6 +8978,7 @@ static void visit_cf_list(isel_context *ctx,
unreachable("unimplemented cf list type");
}
}
return false;
}
static void export_vs_varying(isel_context *ctx, int slot, bool is_pos, int *next_pos)