Support Uint to Int implicit conversions at #extension GL_ARB_gpu_shader5.

Signed-off-by: ZhiqianXia <xzq0528@outlook.com>

Test/GL_ARB_gpu_shader5.u2i.vert

@@ -0,0 +1,11 @@
+#version 150
+#extension GL_ARB_gpu_shader5 : require
+
+uniform int u1;
+uniform int u2;
+out   vec4 result;
+void main()
+{
+    uint v = 0;
+    v = uint(u2) - u1;  // implicit conversions
+}

Test/baseResults/GL_ARB_gpu_shader5.u2i.vert.out

@@ -0,0 +1,57 @@
+GL_ARB_gpu_shader5.u2i.vert
+WARNING: 0:2: '#extension' : extension is only partially supported: GL_ARB_gpu_shader5
+
+Shader version: 150
+Requested GL_ARB_gpu_shader5
+0:? Sequence
+0:7  Function Definition: main( ( global void)
+0:7    Function Parameters: 
+0:9    Sequence
+0:9      Sequence
+0:9        move second child to first child ( temp uint)
+0:9          'v' ( temp uint)
+0:9          Constant:
+0:9            0 (const uint)
+0:10      move second child to first child ( temp uint)
+0:10        'v' ( temp uint)
+0:10        subtract ( temp uint)
+0:10          Convert int to uint ( temp uint)
+0:10            'u2' ( uniform int)
+0:10          Convert int to uint ( temp uint)
+0:10            'u1' ( uniform int)
+0:?   Linker Objects
+0:?     'u1' ( uniform int)
+0:?     'u2' ( uniform int)
+0:?     'result' ( smooth out 4-component vector of float)
+0:?     'gl_VertexID' ( gl_VertexId int VertexId)
+0:?     'gl_InstanceID' ( gl_InstanceId int InstanceId)
+
+
+Linked vertex stage:
+
+
+Shader version: 150
+Requested GL_ARB_gpu_shader5
+0:? Sequence
+0:7  Function Definition: main( ( global void)
+0:7    Function Parameters: 
+0:9    Sequence
+0:9      Sequence
+0:9        move second child to first child ( temp uint)
+0:9          'v' ( temp uint)
+0:9          Constant:
+0:9            0 (const uint)
+0:10      move second child to first child ( temp uint)
+0:10        'v' ( temp uint)
+0:10        subtract ( temp uint)
+0:10          Convert int to uint ( temp uint)
+0:10            'u2' ( uniform int)
+0:10          Convert int to uint ( temp uint)
+0:10            'u1' ( uniform int)
+0:?   Linker Objects
+0:?     'u1' ( uniform int)
+0:?     'u2' ( uniform int)
+0:?     'result' ( smooth out 4-component vector of float)
+0:?     'gl_VertexID' ( gl_VertexId int VertexId)
+0:?     'gl_InstanceID' ( gl_InstanceId int InstanceId)
+

glslang/MachineIndependent/Intermediate.cpp

@@ -1739,7 +1739,7 @@ bool TIntermediate::canImplicitlyPromote(TBasicType from, TBasicType to, TOperat
         case EbtUint:
             switch (from) {
             case EbtInt:
-                return version >= 400 || getSource() == EShSourceHlsl;
+                return version >= 400 || getSource() == EShSourceHlsl || IsRequestedExtension(E_GL_ARB_gpu_shader5);
             case EbtBool:
                 return getSource() == EShSourceHlsl;
             case EbtInt16:

glslang/MachineIndependent/localintermediate.h

@@ -926,6 +926,11 @@ public:
         return false;
     }
 
+    bool IsRequestedExtension(const char* extension) const
+    {
+        return (requestedExtensions.find(extension) != requestedExtensions.end());
+    }
+
     void addToCallGraph(TInfoSink&, const TString& caller, const TString& callee);
     void merge(TInfoSink&, TIntermediate&);
     void finalCheck(TInfoSink&, bool keepUncalled);

gtests/AST.FromFile.cpp

@@ -282,6 +282,7 @@ INSTANTIATE_TEST_SUITE_P(
         "terminate.vert",
         "negativeWorkGroupSize.comp",
         "textureoffset_sampler2darrayshadow.vert",
+        "GL_ARB_gpu_shader5.u2i.vert",
     })),
     FileNameAsCustomTestSuffix
 );