Fix for IO conditions in pipelined loops in FSM mode.

PiperOrigin-RevId: 605452944
google · Feb 9, 2024 · bea249d · bea249d
1 parent e55d8a1
commit bea249d
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Showing 2 changed files with 143 additions and 2 deletions.
diff --git a/xls/contrib/xlscc/translate_block.cc b/xls/contrib/xlscc/translate_block.cc
@@ -973,13 +973,20 @@ absl::StatusOr<Translator::SubFSMReturn> Translator::GenerateSubFSM(
                         outer_prepared.xls_func->return_value_count, body_loc);
 
   xls::BValue context_out = pb.TupleIndex(ret_io_value, /*idx=*/0, body_loc);
+  xls::BValue enter_condition =
+      pb.TupleIndex(ret_io_value, /*idx=*/1, body_loc);
+  XLS_CHECK_EQ(enter_condition.GetType()->GetFlatBitCount(), 1);
 
   // Generate inner FSM
   XLS_ASSIGN_OR_RETURN(
       PipelinedLoopContentsReturn contents_ret,
       GenerateIR_PipelinedLoopContents(
           *sub_proc_invoked, pb, outer_prepared.token, context_out,
-          /*in_state_condition=*/outer_state.in_this_state,
+          /*in_state_condition=*/
+          pb.And(outer_state.in_this_state, enter_condition, body_loc,
+                 /*name=*/
+                 absl::StrFormat("%s_loop_contents_condition",
+                                 sub_proc_invoked->name_prefix)),
           /*in_fsm=*/true));
 
   outer_prepared.token = contents_ret.token_out;
@@ -1001,8 +1008,17 @@ absl::StatusOr<Translator::SubFSMReturn> Translator::GenerateSubFSM(
       absl::StrFormat("%s_state_%i_context_receive_invoke", fsm_prefix,
                       outer_state.index));
 
+  xls::BValue not_enter_condition = pb.Not(
+      enter_condition, body_loc,
+      /*name=*/
+      absl::StrFormat("%s_not_enter_condition", sub_proc_invoked->name_prefix));
+
   return SubFSMReturn{
-      .exit_state_condition = contents_ret.do_break,
+      .exit_state_condition =
+          pb.Or(not_enter_condition, contents_ret.do_break, body_loc,
+                /*name=*/
+                absl::StrFormat("%s_not_exit_state_condition",
+                                sub_proc_invoked->name_prefix)),
       .return_value = context_receive_ret_val,
       .extra_next_state_values = contents_ret.extra_next_state_values};
 }

diff --git a/xls/contrib/xlscc/unit_tests/translator_proc_test.cc b/xls/contrib/xlscc/unit_tests/translator_proc_test.cc
@@ -6678,6 +6678,131 @@ TEST_P(TranslatorProcTest, PipelinedLoopSerialDataDependency) {
   }
 }
 
+TEST_P(TranslatorProcTest, PipelinedLoopConditionFalse) {
+  const std::string content = R"(
+       class Block {
+        public:
+         __xls_channel<int, __xls_channel_dir_In>& in;
+         __xls_channel<int, __xls_channel_dir_Out>& out;
+
+         #pragma hls_top
+         void Run() {
+          int value = in.read();
+
+          #pragma hls_pipeline_init_interval 1
+          for(int i=0;i<0;++i) {
+            out.write(55);
+          }
+
+          #pragma hls_pipeline_init_interval 1
+          for(int i=0;i<6;++i) {
+            out.write(value++);
+          }
+        }
+      };)";
+
+  absl::flat_hash_map<std::string, std::list<xls::Value>> inputs;
+  inputs["in"] = {xls::Value(xls::SBits(11, 32))};
+
+  {
+    absl::flat_hash_map<std::string, std::list<xls::Value>> outputs;
+    outputs["out"] = {
+        xls::Value(xls::SBits(11 + 0, 32)), xls::Value(xls::SBits(11 + 1, 32)),
+        xls::Value(xls::SBits(11 + 2, 32)), xls::Value(xls::SBits(11 + 3, 32)),
+        xls::Value(xls::SBits(11 + 4, 32)), xls::Value(xls::SBits(11 + 5, 32))};
+    ProcTest(content, /*block_spec=*/std::nullopt, inputs, outputs,
+             /* min_ticks = */ 1,
+             /* max_ticks = */ 100,
+             /* top_level_init_interval = */ 1);
+  }
+}
+
+TEST_P(TranslatorProcTest, PipelinedLoopConditional) {
+  const std::string content = R"(
+       class Block {
+        public:
+         __xls_channel<int, __xls_channel_dir_In>& in;
+         __xls_channel<int, __xls_channel_dir_Out>& out;
+
+         #pragma hls_top
+         void Run() {
+          int value = in.read();
+
+          if(0) {
+            #pragma hls_pipeline_init_interval 1
+            for(int i=0;i<0;++i) {
+              out.write(55);
+            }
+          }
+
+          if(1) {
+            #pragma hls_pipeline_init_interval 1
+            for(int i=0;i<6;++i) {
+              out.write(value++);
+            }
+          }
+        }
+      };)";
+
+  absl::flat_hash_map<std::string, std::list<xls::Value>> inputs;
+  inputs["in"] = {xls::Value(xls::SBits(11, 32))};
+
+  {
+    absl::flat_hash_map<std::string, std::list<xls::Value>> outputs;
+    outputs["out"] = {
+        xls::Value(xls::SBits(11 + 0, 32)), xls::Value(xls::SBits(11 + 1, 32)),
+        xls::Value(xls::SBits(11 + 2, 32)), xls::Value(xls::SBits(11 + 3, 32)),
+        xls::Value(xls::SBits(11 + 4, 32)), xls::Value(xls::SBits(11 + 5, 32))};
+    ProcTest(content, /*block_spec=*/std::nullopt, inputs, outputs,
+             /* min_ticks = */ 1,
+             /* max_ticks = */ 100,
+             /* top_level_init_interval = */ 1);
+  }
+}
+
+TEST_P(TranslatorProcTest, PipelinedLoopConditional2) {
+  const std::string content = R"(
+       class Block {
+        public:
+         __xls_channel<int, __xls_channel_dir_In>& in;
+         __xls_channel<int, __xls_channel_dir_Out>& out;
+
+         #pragma hls_top
+         void Run() {
+          int value = in.read();
+
+          if(0) {
+            #pragma hls_pipeline_init_interval 1
+            for(int i=0;i<1;++i) {
+              ++value;
+            }
+          }
+
+          if(1) {
+            #pragma hls_pipeline_init_interval 1
+            for(int i=0;i<6;++i) {
+              out.write(value++);
+            }
+          }
+        }
+      };)";
+
+  absl::flat_hash_map<std::string, std::list<xls::Value>> inputs;
+  inputs["in"] = {xls::Value(xls::SBits(11, 32))};
+
+  {
+    absl::flat_hash_map<std::string, std::list<xls::Value>> outputs;
+    outputs["out"] = {
+        xls::Value(xls::SBits(11 + 0, 32)), xls::Value(xls::SBits(11 + 1, 32)),
+        xls::Value(xls::SBits(11 + 2, 32)), xls::Value(xls::SBits(11 + 3, 32)),
+        xls::Value(xls::SBits(11 + 4, 32)), xls::Value(xls::SBits(11 + 5, 32))};
+    ProcTest(content, /*block_spec=*/std::nullopt, inputs, outputs,
+             /* min_ticks = */ 1,
+             /* max_ticks = */ 100,
+             /* top_level_init_interval = */ 1);
+  }
+}
+
 TEST_P(TranslatorProcTest, PipelinedLoopSerialAfterASAP) {
   const std::string content = R"(
        class Block {