Check if we can use multiple initializers.

Need same type and qualifiers in GLSL and friends.

reference/shaders/comp/cfg.comp

@@ -63,9 +63,8 @@ void test()
             break;
         }
     }
-    int i = 0;
     float h;
-    for (; i < 20; i = i + 1, h = h + 10.0)
+    for (int i = 0; i < 20; i = i + 1, h = h + 10.0)
     {
     }
     _11.data = h;

reference/shaders/comp/loop.comp

@@ -60,11 +60,9 @@ void main()
         idat = idat * 2.0;
         k = k + 1;
     }
-    uint i_1 = 0u;
-    for (; i_1 < 16u; i_1 = i_1 + uint(1), k = k + 1)
+    for (uint i_1 = 0u; i_1 < 16u; i_1 = i_1 + uint(1), k = k + 1)
     {
-        uint j = 0u;
-        for (; j < 30u; j = j + uint(1))
+        for (uint j = 0u; j < 30u; j = j + uint(1))
         {
             idat = _24.mvp * idat;
         }

reference/shaders/comp/return.comp

@@ -21,8 +21,7 @@ void main()
             return;
         }
     }
-    int i = 0;
-    for (; i < 20; i = i + 1)
+    for (int i = 0; i < 20; i = i + 1)
     {
         if (i == 10)
         {

reference/shaders/comp/torture-loop.comp

@@ -33,11 +33,9 @@ void main()
             break;
         }
     }
-    uint i = 0u;
-    for (; i < 16u; i = i + uint(1), k = k + 1)
+    for (uint i = 0u; i < 16u; i = i + uint(1), k = k + 1)
     {
-        uint j = 0u;
-        for (; j < 30u; j = j + uint(1))
+        for (uint j = 0u; j < 30u; j = j + uint(1))
         {
             idat = _24.mvp * idat;
         }

spirv_glsl.cpp

@@ -5354,7 +5354,38 @@ void CompilerGLSL::emit_function(SPIRFunction &func, uint64_t return_flags)
 	if (!func.analyzed_variable_scope)
 	{
 		if (options.cfg_analysis)
+		{
 			analyze_variable_scope(func);
+
+			// Check if we can actually use the loop variables we found in analyze_variable_scope.
+			// To use multiple initializers, we need the same type and qualifiers.
+			for (auto block : func.blocks)
+			{
+				auto &b = get<SPIRBlock>(block);
+				if (b.loop_variables.size() < 2)
+					continue;
+
+				uint64_t flags = get_decoration_mask(b.loop_variables.front());
+				uint32_t type = get<SPIRVariable>(b.loop_variables.front()).basetype;
+				bool invalid_initializers = false;
+				for (auto loop_variable : b.loop_variables)
+				{
+					if (flags != get_decoration_mask(loop_variable) ||
+					    type != get<SPIRVariable>(b.loop_variables.front()).basetype)
+					{
+						invalid_initializers = true;
+						break;
+					}
+				}
+
+				if (invalid_initializers)
+				{
+					for (auto loop_variable : b.loop_variables)
+						get<SPIRVariable>(loop_variable).loop_variable = false;
+					b.loop_variables.clear();
+				}
+			}
+		}
 		else
 			entry_block.dominated_variables = func.local_variables;
 		func.analyzed_variable_scope = true;