glasm: Catch more register leaks

Add support for null registers. These are used when an instruction has
no usages.

This comes handy when an instruction is only used for its CC value, with
the caveat of having to invalidate all pseudo-instructions before
defining the instruction itself in the register allocator. This commits
changes this.

Workaround a bug on Nvidia's condition codes conditional execution using
branches.

1 files changed, 17 insertions, 10 deletions

diff --git a/src/shader_recompiler/backend/glasm/emit_glasm_image.cpp b/src/shader_recompiler/backend/glasm/emit_glasm_image.cpp
index a7def0897..34725b8c6 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm_image.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm_image.cpp
@@ -181,7 +181,6 @@ void StoreSparse(EmitContext& ctx, IR::Inst* sparse_inst) {
     ctx.Add("MOV.S {},-1;"
             "MOV.S {}(NONRESIDENT),0;",
             sparse_ret, sparse_ret);
-    sparse_inst->Invalidate();
 }
 
 std::string_view FormatStorage(ImageFormat format) {
@@ -215,12 +214,20 @@ void ImageAtomic(EmitContext& ctx, IR::Inst& inst, const IR::Value& index, Regis
     const Register ret{ctx.reg_alloc.Define(inst)};
     ctx.Add("ATOMIM.{} {},{},{},{},{};", op, ret, value, coord, image, type);
 }
+
+IR::Inst* PrepareSparse(IR::Inst& inst) {
+    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    if (sparse_inst) {
+        sparse_inst->Invalidate();
+    }
+    return sparse_inst;
+}
 } // Anonymous namespace
 
 void EmitImageSampleImplicitLod(EmitContext& ctx, IR::Inst& inst, const IR::Value& index,
                                 const IR::Value& coord, Register bias_lc, const IR::Value& offset) {
     const auto info{inst.Flags<IR::TextureInstInfo>()};
-    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const auto sparse_inst{PrepareSparse(inst)};
     const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
     const std::string_view lod_clamp_mod{info.has_lod_clamp ? ".LODCLAMP" : ""};
     const std::string_view type{TextureType(info)};
@@ -259,7 +266,7 @@ void EmitImageSampleImplicitLod(EmitContext& ctx, IR::Inst& inst, const IR::Valu
 void EmitImageSampleExplicitLod(EmitContext& ctx, IR::Inst& inst, const IR::Value& index,
                                 const IR::Value& coord, ScalarF32 lod, const IR::Value& offset) {
     const auto info{inst.Flags<IR::TextureInstInfo>()};
-    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const auto sparse_inst{PrepareSparse(inst)};
     const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
     const std::string_view type{TextureType(info)};
     const std::string texture{Texture(ctx, info, index)};
@@ -288,7 +295,7 @@ void EmitImageSampleDrefImplicitLod(EmitContext& ctx, IR::Inst& inst, const IR::
     }
     const ScalarF32 dref_val{ctx.reg_alloc.Consume(dref)};
     const Register bias_lc_vec{ctx.reg_alloc.Consume(bias_lc)};
-    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const auto sparse_inst{PrepareSparse(inst)};
     const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
     const std::string_view type{TextureType(info)};
     const std::string texture{Texture(ctx, info, index)};
@@ -393,7 +400,7 @@ void EmitImageSampleDrefExplicitLod(EmitContext& ctx, IR::Inst& inst, const IR::
     }
     const ScalarF32 dref_val{ctx.reg_alloc.Consume(dref)};
     const ScalarF32 lod_val{ctx.reg_alloc.Consume(lod)};
-    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const auto sparse_inst{PrepareSparse(inst)};
     const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
     const std::string_view type{TextureType(info)};
     const std::string texture{Texture(ctx, info, index)};
@@ -436,7 +443,7 @@ void EmitImageGather(EmitContext& ctx, IR::Inst& inst, const IR::Value& index,
     const auto [off_x, off_y]{AllocOffsetsRegs(ctx, offset2)};
     const auto info{inst.Flags<IR::TextureInstInfo>()};
     const char comp{"xyzw"[info.gather_component]};
-    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const auto sparse_inst{PrepareSparse(inst)};
     const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
     const std::string_view type{TextureType(info)};
     const std::string texture{Texture(ctx, info, index)};
@@ -462,7 +469,7 @@ void EmitImageGatherDref(EmitContext& ctx, IR::Inst& inst, const IR::Value& inde
     // Allocate offsets early so they don't overwrite any consumed register
     const auto [off_x, off_y]{AllocOffsetsRegs(ctx, offset2)};
     const auto info{inst.Flags<IR::TextureInstInfo>()};
-    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const auto sparse_inst{PrepareSparse(inst)};
     const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
     const std::string_view type{TextureType(info)};
     const std::string texture{Texture(ctx, info, index)};
@@ -500,7 +507,7 @@ void EmitImageGatherDref(EmitContext& ctx, IR::Inst& inst, const IR::Value& inde
 void EmitImageFetch(EmitContext& ctx, IR::Inst& inst, const IR::Value& index,
                     const IR::Value& coord, const IR::Value& offset, ScalarS32 lod, ScalarS32 ms) {
     const auto info{inst.Flags<IR::TextureInstInfo>()};
-    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const auto sparse_inst{PrepareSparse(inst)};
     const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
     const std::string_view type{TextureType(info)};
     const std::string texture{Texture(ctx, info, index)};
@@ -547,7 +554,7 @@ void EmitImageGradient(EmitContext& ctx, IR::Inst& inst, const IR::Value& index,
         dpdx = ScopedRegister{ctx.reg_alloc};
         dpdy = ScopedRegister{ctx.reg_alloc};
     }
-    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const auto sparse_inst{PrepareSparse(inst)};
     const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
     const std::string_view type{TextureType(info)};
     const std::string texture{Texture(ctx, info, index)};
@@ -581,7 +588,7 @@ void EmitImageGradient(EmitContext& ctx, IR::Inst& inst, const IR::Value& index,
 
 void EmitImageRead(EmitContext& ctx, IR::Inst& inst, const IR::Value& index, Register coord) {
     const auto info{inst.Flags<IR::TextureInstInfo>()};
-    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const auto sparse_inst{PrepareSparse(inst)};
     const std::string_view format{FormatStorage(info.image_format)};
     const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
     const std::string_view type{TextureType(info)};