Test dead-decoration removal.

Test/baseResults/spv.noDeadDecorations.vert.out

+spv.noDeadDecorations.vert
+Warning, version 310 is not yet complete; most version-specific features are present, but some are missing.
+
+
+Linked vertex stage:
+
+
+// Module Version 10000
+// Generated by (magic number): 80001
+// Id's are bound by 32
+
+                              Capability Shader
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Vertex 4  "main" 22
+                              Source ESSL 310
+                              Name 4  "main"
+                              Name 10  "func(f1;"
+                              Name 9  "a"
+                              Name 20  "gl_PerVertex"
+                              MemberName 20(gl_PerVertex) 0  "gl_Position"
+                              MemberName 20(gl_PerVertex) 1  "gl_PointSize"
+                              Name 22  ""
+                              Name 26  "param"
+                              Decorate 10(func(f1;) RelaxedPrecision
+                              Decorate 9(a) RelaxedPrecision
+                              Decorate 12 RelaxedPrecision
+                              Decorate 13 RelaxedPrecision
+                              MemberDecorate 20(gl_PerVertex) 0 BuiltIn Position
+                              MemberDecorate 20(gl_PerVertex) 1 BuiltIn PointSize
+                              Decorate 20(gl_PerVertex) Block
+                              Decorate 27 RelaxedPrecision
+               2:             TypeVoid
+               3:             TypeFunction 2
+               6:             TypeFloat 32
+               7:             TypePointer Function 6(float)
+               8:             TypeFunction 6(float) 7(ptr)
+              16:    6(float) Constant 3212836864
+              19:             TypeVector 6(float) 4
+20(gl_PerVertex):             TypeStruct 19(fvec4) 6(float)
+              21:             TypePointer Output 20(gl_PerVertex)
+              22:     21(ptr) Variable Output
+              23:             TypeInt 32 1
+              24:     23(int) Constant 0
+              25:    6(float) Constant 0
+              28:             TypeInt 32 0
+              29:     28(int) Constant 0
+              30:             TypePointer Output 6(float)
+         4(main):           2 Function None 3
+               5:             Label
+       26(param):      7(ptr) Variable Function
+                              Store 26(param) 25
+              27:    6(float) FunctionCall 10(func(f1;) 26(param)
+              31:     30(ptr) AccessChain 22 24 29
+                              Store 31 27
+                              Return
+                              FunctionEnd
+    10(func(f1;):    6(float) Function None 8
+            9(a):      7(ptr) FunctionParameter
+              11:             Label
+              12:    6(float) Load 9(a)
+              13:    6(float) FNegate 12
+                              ReturnValue 13
+                              FunctionEnd

Test/spv.noDeadDecorations.vert

+#version 310 es
+precision mediump float;
+
+float func(float a)
+{
+    return -a;
+    a = a * -1.0;
+}
+
+void main()
+{
+    gl_Position.x = func(0.0);
+}

Test/test-spirv-list

@@ -64,6 +64,7 @@ spv.matrix2.frag
 spv.memoryQualifier.frag
 spv.merge-unreachable.frag
 spv.newTexture.frag
+spv.noDeadDecorations.vert
 spv.nonSquare.vert
 spv.Operations.frag
 spv.intOps.vert