From 441294962cd65d44febdbe9ef0b0d99b5d27cec8 Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Thu, 14 Feb 2019 09:42:38 -0800
Subject: [PATCH] v3d: Fix the check for "is the last thrsw inside control
 flow"

The execute.file check used to be good enough, until I stopped setting up
the execute mask for uniform ifs.

No known tests fixed, noticed while doing a refactor.

Fixes: 080506057310 ("v3d: Handle dynamically uniform IF statements with uniform control flow.")
---
 src/broadcom/compiler/nir_to_vir.c   | 24 ++++++++++++++++--------
 src/broadcom/compiler/v3d_compiler.h |  1 +
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/broadcom/compiler/nir_to_vir.c b/src/broadcom/compiler/nir_to_vir.c
index 86f4a3a12c1..7ab3b4f60ce 100644
--- a/src/broadcom/compiler/nir_to_vir.c
+++ b/src/broadcom/compiler/nir_to_vir.c
@@ -121,7 +121,7 @@ vir_emit_thrsw(struct v3d_compile *c)
          */
         c->last_thrsw = vir_NOP(c);
         c->last_thrsw->qpu.sig.thrsw = true;
-        c->last_thrsw_at_top_level = (c->execute.file == QFILE_NULL);
+        c->last_thrsw_at_top_level = !c->in_control_flow;
 }
 
 static uint32_t
@@ -2085,10 +2085,10 @@ ntq_emit_nonuniform_if(struct v3d_compile *c, nir_if *if_stmt)
         else
                 else_block = vir_new_block(c);
 
-        bool was_top_level = false;
+        bool was_uniform_control_flow = false;
         if (c->execute.file == QFILE_NULL) {
                 c->execute = vir_MOV(c, vir_uniform_ui(c, 0));
-                was_top_level = true;
+                was_uniform_control_flow = true;
         }
 
         /* Set up the flags for the IF condition (taking the THEN branch). */
@@ -2097,7 +2097,7 @@ ntq_emit_nonuniform_if(struct v3d_compile *c, nir_if *if_stmt)
         /* Update the flags+cond to mean "Taking the ELSE branch (!cond) and
          * was previously active (execute Z) for updating the exec flags.
          */
-        if (was_top_level) {
+        if (was_uniform_control_flow) {
                 cond = v3d_qpu_cond_invert(cond);
         } else {
                 struct qinst *inst = vir_MOV_dest(c, vir_nop_reg(), c->execute);
@@ -2152,7 +2152,7 @@ ntq_emit_nonuniform_if(struct v3d_compile *c, nir_if *if_stmt)
         vir_link_blocks(c->cur_block, after_block);
 
         vir_set_emit_block(c, after_block);
-        if (was_top_level)
+        if (was_uniform_control_flow)
                 c->execute = c->undef;
         else
                 ntq_activate_execute_for_block(c);
@@ -2161,12 +2161,15 @@ ntq_emit_nonuniform_if(struct v3d_compile *c, nir_if *if_stmt)
 static void
 ntq_emit_if(struct v3d_compile *c, nir_if *nif)
 {
+        bool was_in_control_flow = c->in_control_flow;
+        c->in_control_flow = true;
         if (c->execute.file == QFILE_NULL &&
             nir_src_is_dynamically_uniform(nif->condition)) {
                 ntq_emit_uniform_if(c, nif);
         } else {
                 ntq_emit_nonuniform_if(c, nif);
         }
+        c->in_control_flow = was_in_control_flow;
 }
 
 static void
@@ -2245,10 +2248,13 @@ static void ntq_emit_cf_list(struct v3d_compile *c, struct exec_list *list);
 static void
 ntq_emit_loop(struct v3d_compile *c, nir_loop *loop)
 {
-        bool was_top_level = false;
+        bool was_in_control_flow = c->in_control_flow;
+        c->in_control_flow = true;
+
+        bool was_uniform_control_flow = false;
         if (c->execute.file == QFILE_NULL) {
                 c->execute = vir_MOV(c, vir_uniform_ui(c, 0));
-                was_top_level = true;
+                was_uniform_control_flow = true;
         }
 
         struct qblock *save_loop_cont_block = c->loop_cont_block;
@@ -2286,7 +2292,7 @@ ntq_emit_loop(struct v3d_compile *c, nir_loop *loop)
         vir_link_blocks(c->cur_block, c->loop_break_block);
 
         vir_set_emit_block(c, c->loop_break_block);
-        if (was_top_level)
+        if (was_uniform_control_flow)
                 c->execute = c->undef;
         else
                 ntq_activate_execute_for_block(c);
@@ -2295,6 +2301,8 @@ ntq_emit_loop(struct v3d_compile *c, nir_loop *loop)
         c->loop_cont_block = save_loop_cont_block;
 
         c->loops++;
+
+        c->in_control_flow = was_in_control_flow;
 }
 
 static void
diff --git a/src/broadcom/compiler/v3d_compiler.h b/src/broadcom/compiler/v3d_compiler.h
index d29579b8f35..3817afe5ce6 100644
--- a/src/broadcom/compiler/v3d_compiler.h
+++ b/src/broadcom/compiler/v3d_compiler.h
@@ -538,6 +538,7 @@ struct v3d_compile {
          * yes, otherwise a block number + 1 that the channel jumped to.
          */
         struct qreg execute;
+        bool in_control_flow;
 
         struct qreg line_x, point_x, point_y;
 
-- 
2.30.2