From 100a4bd98856cf16c1fe16b6c1f1ab2863916c37 Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Sun, 22 Sep 2019 20:15:09 -0400
Subject: vk_shader_compiler: Don't enclose branches with if(true) to avoid
 crashing AMD

---
 .../renderer_vulkan/vk_shader_decompiler.cpp       | 49 +++++++++++++++-------
 1 file changed, 33 insertions(+), 16 deletions(-)

(limited to 'src/video_core/renderer_vulkan')

diff --git a/src/video_core/renderer_vulkan/vk_shader_decompiler.cpp b/src/video_core/renderer_vulkan/vk_shader_decompiler.cpp
index 4527e9261..11effe4a1 100644
--- a/src/video_core/renderer_vulkan/vk_shader_decompiler.cpp
+++ b/src/video_core/renderer_vulkan/vk_shader_decompiler.cpp
@@ -646,7 +646,9 @@ private:
             Emit(OpBranchConditional(condition, true_label, skip_label));
             Emit(true_label);
 
+            ++conditional_nest_count;
             VisitBasicBlock(conditional->GetCode());
+            --conditional_nest_count;
 
             Emit(OpBranch(skip_label));
             Emit(skip_label);
@@ -1011,7 +1013,10 @@ private:
         UNIMPLEMENTED_IF(!target);
 
         Emit(OpStore(jmp_to, Constant(t_uint, target->GetValue())));
-        BranchingOp([&]() { Emit(OpBranch(continue_label)); });
+        Emit(OpBranch(continue_label));
+        if (conditional_nest_count == 0) {
+            Emit(OpLabel());
+        }
         return {};
     }
 
@@ -1019,7 +1024,10 @@ private:
         const Id op_a = VisitOperand<Type::Uint>(operation, 0);
 
         Emit(OpStore(jmp_to, op_a));
-        BranchingOp([&]() { Emit(OpBranch(continue_label)); });
+        Emit(OpBranch(continue_label));
+        if (conditional_nest_count == 0) {
+            Emit(OpLabel());
+        }
         return {};
     }
 
@@ -1046,7 +1054,10 @@ private:
 
         Emit(OpStore(flow_stack_top, previous));
         Emit(OpStore(jmp_to, target));
-        BranchingOp([&]() { Emit(OpBranch(continue_label)); });
+        Emit(OpBranch(continue_label));
+        if (conditional_nest_count == 0) {
+            Emit(OpLabel());
+        }
         return {};
     }
 
@@ -1103,12 +1114,28 @@ private:
 
     Id Exit(Operation operation) {
         PreExit();
-        BranchingOp([&]() { Emit(OpReturn()); });
+        if (conditional_nest_count > 0) {
+            Emit(OpReturn());
+        } else {
+            const Id dummy = OpLabel();
+            Emit(OpBranch(dummy));
+            Emit(dummy);
+            Emit(OpReturn());
+            Emit(OpLabel());
+        }
         return {};
     }
 
     Id Discard(Operation operation) {
-        BranchingOp([&]() { Emit(OpKill()); });
+        if (conditional_nest_count > 0) {
+            Emit(OpKill());
+        } else {
+            const Id dummy = OpLabel();
+            Emit(OpBranch(dummy));
+            Emit(dummy);
+            Emit(OpKill());
+            Emit(OpLabel());
+        }
         return {};
     }
 
@@ -1303,17 +1330,6 @@ private:
         return {};
     }
 
-    void BranchingOp(std::function<void()> call) {
-        const Id true_label = OpLabel();
-        const Id skip_label = OpLabel();
-        Emit(OpSelectionMerge(skip_label, spv::SelectionControlMask::Flatten));
-        Emit(OpBranchConditional(v_true, true_label, skip_label, 1, 0));
-        Emit(true_label);
-        call();
-
-        Emit(skip_label);
-    }
-
     std::tuple<Id, Id> CreateFlowStack() {
         // TODO(Rodrigo): Figure out the actual depth of the flow stack, for now it seems unlikely
         // that shaders will use 20 nested SSYs and PBKs.
@@ -1519,6 +1535,7 @@ private:
     const ShaderIR& ir;
     const ShaderStage stage;
     const Tegra::Shader::Header header;
+    u64 conditional_nest_count{};
 
     const Id t_void = Name(TypeVoid(), "void");
 
-- 
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