val: fix MSVC warning C4146 (minus on unsigned) (KhronosGroup#6282)

DXC is building with -Werror, and doing `-1u` to get an all ones yiels
a `unary minus operator applied to unsigned type, result still unsigned`
warning.

Author: Keenuts

source/val/validate_composites.cpp

@@ -16,6 +16,8 @@
 
 // Validates correctness of composite SPIR-V instructions.
 
+#include <climits>
+
 #include "source/opcode.h"
 #include "source/spirv_target_env.h"
 #include "source/val/instruction.h"
@@ -640,7 +642,7 @@ spv_result_t ValidateCompositeConstructCoopMatQCOM(ValidationState_t& _,
 
   // Is the scope Subgrouop ?
   {
-    unsigned scope = -1u;
+    unsigned scope = UINT_MAX;
     unsigned scope_id = result_type_inst->GetOperandAs<unsigned>(2u);
     bool status = _.GetConstantValueAs<unsigned>(scope_id, scope);
     bool is_scope_spec_const =
@@ -653,7 +655,7 @@ spv_result_t ValidateCompositeConstructCoopMatQCOM(ValidationState_t& _,
     }
   }
 
-  unsigned ar_len = -1u;
+  unsigned ar_len = UINT_MAX;
   unsigned src_arr_len_id = source_type_inst->GetOperandAs<unsigned>(2u);
   bool ar_len_status = _.GetConstantValueAs<unsigned>(src_arr_len_id, ar_len);
   bool is_src_arr_len_spec_const =
@@ -676,7 +678,7 @@ spv_result_t ValidateCompositeConstructCoopMatQCOM(ValidationState_t& _,
   unsigned res_col_id = result_type_inst->GetOperandAs<unsigned>(4u);
   unsigned res_use_id = result_type_inst->GetOperandAs<unsigned>(5u);
 
-  unsigned cm_use = -1u;
+  unsigned cm_use = UINT_MAX;
   bool cm_use_status = _.GetConstantValueAs<unsigned>(res_use_id, cm_use);
 
   switch (static_cast<spv::CooperativeMatrixUse>(cm_use)) {
@@ -691,7 +693,7 @@ spv_result_t ValidateCompositeConstructCoopMatQCOM(ValidationState_t& _,
       }
 
       // result coopmat column length check
-      unsigned n_cols = -1u;
+      unsigned n_cols = UINT_MAX;
       bool status = _.GetConstantValueAs<unsigned>(res_col_id, n_cols);
       bool is_res_col_spec_const =
           spvOpcodeIsSpecConstant(_.FindDef(res_col_id)->opcode());
@@ -738,7 +740,7 @@ spv_result_t ValidateCompositeConstructCoopMatQCOM(ValidationState_t& _,
       }
 
       // result coopmat row length check
-      unsigned n_rows = -1u;
+      unsigned n_rows = UINT_MAX;
       bool status = _.GetConstantValueAs<unsigned>(res_row_id, n_rows);
       bool is_res_row_spec_const =
           spvOpcodeIsSpecConstant(_.FindDef(res_row_id)->opcode());
@@ -785,7 +787,7 @@ spv_result_t ValidateCompositeConstructCoopMatQCOM(ValidationState_t& _,
       }
 
       // source array length check
-      unsigned n_cols = -1u;
+      unsigned n_cols = UINT_MAX;
       bool status = _.GetConstantValueAs<unsigned>(res_col_id, n_cols);
       bool is_res_col_spec_const =
           spvOpcodeIsSpecConstant(_.FindDef(res_col_id)->opcode());
@@ -848,7 +850,7 @@ spv_result_t ValidateCompositeExtractCoopMatQCOM(ValidationState_t& _,
 
   // Is the scope Subgrouop ?
   {
-    unsigned scope = -1u;
+    unsigned scope = UINT_MAX;
     unsigned scope_id = source_type_inst->GetOperandAs<unsigned>(2u);
     bool status = _.GetConstantValueAs<unsigned>(scope_id, scope);
     bool is_scope_spec_const =
@@ -861,7 +863,7 @@ spv_result_t ValidateCompositeExtractCoopMatQCOM(ValidationState_t& _,
     }
   }
 
-  unsigned ar_len = -1u;
+  unsigned ar_len = UINT_MAX;
   unsigned res_arr_len_id = result_type_inst->GetOperandAs<unsigned>(2u);
   bool ar_len_status = _.GetConstantValueAs<unsigned>(res_arr_len_id, ar_len);
   bool is_res_arr_len_spec_const =
@@ -874,7 +876,7 @@ spv_result_t ValidateCompositeExtractCoopMatQCOM(ValidationState_t& _,
   unsigned src_col_id = source_type_inst->GetOperandAs<unsigned>(4u);
   unsigned src_use_id = source_type_inst->GetOperandAs<unsigned>(5u);
 
-  unsigned cm_use = -1u;
+  unsigned cm_use = UINT_MAX;
   bool cm_use_status = _.GetConstantValueAs<unsigned>(src_use_id, cm_use);
 
   switch (static_cast<spv::CooperativeMatrixUse>(cm_use)) {
@@ -889,7 +891,7 @@ spv_result_t ValidateCompositeExtractCoopMatQCOM(ValidationState_t& _,
       }
 
       // source coopmat column length check
-      unsigned n_cols = -1u;
+      unsigned n_cols = UINT_MAX;
       bool status = _.GetConstantValueAs<unsigned>(src_col_id, n_cols);
       bool is_src_col_spec_const =
           spvOpcodeIsSpecConstant(_.FindDef(src_col_id)->opcode());
@@ -937,7 +939,7 @@ spv_result_t ValidateCompositeExtractCoopMatQCOM(ValidationState_t& _,
       }
 
       // source coopmat row length check
-      unsigned n_rows = -1u;
+      unsigned n_rows = UINT_MAX;
       bool status = _.GetConstantValueAs<unsigned>(src_row_id, n_rows);
       bool is_src_row_spec_const =
           spvOpcodeIsSpecConstant(_.FindDef(src_row_id)->opcode());
@@ -985,7 +987,7 @@ spv_result_t ValidateCompositeExtractCoopMatQCOM(ValidationState_t& _,
       }
 
       // result type check
-      unsigned n_cols = -1u;
+      unsigned n_cols = UINT_MAX;
       bool status = _.GetConstantValueAs<unsigned>(src_col_id, n_cols);
       bool is_src_col_spec_const =
           spvOpcodeIsSpecConstant(_.FindDef(src_col_id)->opcode());