Enforce stable order for dominated phi variables.

reference/opt/shaders-msl/asm/frag/undef-variable-store.asm.frag

@@ -18,8 +18,8 @@ fragment main0_out main0()
     float4 _20;
     float4 _21;
     float4 _38;
-    float4 _52;
     float4 _51;
+    float4 _52;
     _51 = _50;
     for (;;)
     {

reference/opt/shaders-msl/comp/loop.comp

@@ -43,8 +43,8 @@ kernel void main0(uint3 gl_GlobalInvocationID [[thread_position_in_grid]], devic
     uint _186;
     if (_24.in_data[gl_GlobalInvocationID.x].y == 20.0)
     {
-        uint _184;
         int _183;
+        uint _184;
         _183 = 0;
         _184 = 0u;
         for (;;)

reference/opt/shaders-msl/comp/torture-loop.comp

@@ -31,8 +31,8 @@ kernel void main0(uint3 gl_GlobalInvocationID [[thread_position_in_grid]], devic
     uint _73;
     int _83;
     _30 = _24.in_data[gl_GlobalInvocationID.x];
-    int _94;
     float4 _93;
+    int _94;
     _93 = _30;
     _94 = 0;
     for (;;)
@@ -55,8 +55,8 @@ kernel void main0(uint3 gl_GlobalInvocationID [[thread_position_in_grid]], devic
     int _96;
     _95 = _93;
     _96 = _40;
-    uint _101;
     float4 _100;
+    uint _101;
     for (uint _97 = 0u, _99 = _98; _97 < 16u; _75 = _97 + uint(1), _77 = _96 + 1, _95 = _100, _96 = _77, _97 = _75, _99 = _101)
     {
         _100 = _95;

reference/opt/shaders/asm/frag/undef-variable-store.asm.frag

@@ -11,8 +11,8 @@ void main()
     vec4 _20;
     vec4 _21;
     vec4 _38;
-    vec4 _52;
     vec4 _51;
+    vec4 _52;
     _51 = _50;
     for (;;)
     {

reference/opt/shaders/comp/torture-loop.comp

@@ -29,8 +29,8 @@ void main()
     uint _73;
     int _83;
     _30 = _24.in_data[gl_GlobalInvocationID.x];
-    int _94;
     vec4 _93;
+    int _94;
     _93 = _30;
     _94 = 0;
     for (;;)
@@ -53,8 +53,8 @@ void main()
     int _96;
     _95 = _93;
     _96 = _40;
-    uint _101;
     vec4 _100;
+    uint _101;
     for (uint _97 = 0u, _99 = _98; _97 < 16u; _75 = _97 + uint(1), _77 = _96 + 1, _95 = _100, _96 = _77, _97 = _75, _99 = _101)
     {
         _100 = _95;

spirv_glsl.cpp

@@ -7900,6 +7900,9 @@ bool CompilerGLSL::attempt_emit_loop_header(SPIRBlock &block, SPIRBlock::Method
 
 void CompilerGLSL::flush_undeclared_variables(SPIRBlock &block)
 {
+	// Enforce declaration order for regression testing purposes.
+	sort(begin(block.dominated_variables), end(block.dominated_variables));
+
 	for (auto &v : block.dominated_variables)
 	{
 		auto &var = get<SPIRVariable>(v);