Merge pull request #451 from KhronosGroup/fix-437

Fix case where hoisted temporaries were used before being declared.

reference/opt/shaders/frag/hoisted-temporary-use-continue-block-as-value.frag

@@ -0,0 +1,37 @@
+#version 310 es
+precision mediump float;
+precision highp int;
+
+layout(location = 0) out vec4 FragColor;
+layout(location = 0) flat in mediump int vA;
+layout(location = 1) flat in mediump int vB;
+
+void main()
+{
+    FragColor = vec4(0.0);
+    mediump int _49;
+    int _60;
+    for (int _57 = 0, _58 = 0; _58 < vA; _57 = _60, _58 += _49)
+    {
+        if ((vA + _58) == 20)
+        {
+            _60 = 50;
+        }
+        else
+        {
+            int _59;
+            if ((vB + _58) == 40)
+            {
+                _59 = 60;
+            }
+            else
+            {
+                _59 = _57;
+            }
+            _60 = _59;
+        }
+        _49 = _60 + 10;
+        FragColor += vec4(1.0);
+    }
+}
+

reference/shaders/frag/hoisted-temporary-use-continue-block-as-value.frag

@@ -0,0 +1,31 @@
+#version 310 es
+precision mediump float;
+precision highp int;
+
+layout(location = 0) out vec4 FragColor;
+layout(location = 0) flat in mediump int vA;
+layout(location = 1) flat in mediump int vB;
+
+void main()
+{
+    FragColor = vec4(0.0);
+    mediump int k = 0;
+    mediump int j;
+    for (mediump int i = 0; i < vA; i += j)
+    {
+        if ((vA + i) == 20)
+        {
+            k = 50;
+        }
+        else
+        {
+            if ((vB + i) == 40)
+            {
+                k = 60;
+            }
+        }
+        j = k + 10;
+        FragColor += vec4(1.0);
+    }
+}
+

shaders/frag/hoisted-temporary-use-continue-block-as-value.frag

@@ -0,0 +1,24 @@
+#version 310 es
+precision mediump float;
+
+layout(location = 0) out vec4 FragColor;
+layout(location = 0) flat in int vA;
+layout(location = 1) flat in int vB;
+
+void main()
+{
+	FragColor = vec4(0.0);
+
+	int k = 0;
+	int j;
+	for (int i = 0; i < vA; i += j)
+	{
+		if ((vA + i) == 20)
+			k = 50;
+		else if ((vB + i) == 40)
+			k = 60;
+
+		j = k + 10;
+		FragColor += 1.0;
+	}
+}

spirv_glsl.cpp

@@ -8336,6 +8336,9 @@ void CompilerGLSL::emit_block_chain(SPIRBlock &block)
 		auto flags = meta[tmp.second].decoration.decoration_flags;
 		auto &type = get<SPIRType>(tmp.first);
 		statement(flags_to_precision_qualifiers_glsl(type, flags), variable_decl(type, to_name(tmp.second)), ";");
+
+		// The temporary might be read from before it's assigned, set up the expression now.
+		set<SPIRExpression>(tmp.second, to_name(tmp.second), tmp.first, true);
 	}
 
 	SPIRBlock::ContinueBlockType continue_type = SPIRBlock::ContinueNone;