Add comments to tests for clarity of purpose

Author: Icohedron

llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-0.ll

@@ -1,5 +1,9 @@
 ; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
 
+; This test checks to ensure that setting the LLVM module flag "dx.resmayalias"
+; to 0 has no effect on the DXIL shader flag analysis for the flag
+; ResMayNotAlias.
+
 target triple = "dxil-pc-shadermodel6.8-library"
 
 ; CHECK:      Combined Shader Flags for Module

llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-1.ll

@@ -1,5 +1,9 @@
 ; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
 
+; This test checks to ensure that setting the LLVM module flag "dx.resmayalias"
+; to 1 prevents the DXIL shader flag analysis from setting the flag
+; ResMayNotAlias.
+
 target triple = "dxil-pc-shadermodel6.8-library"
 
 ; CHECK:      Combined Shader Flags for Module

llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.6.ll

@@ -1,5 +1,9 @@
 ; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
 
+; This test checks to ensure the behavior of the DXIL shader flag analysis
+; for the flag ResMayNotAlias is correct when the DXIL Version is 1.6. The
+; ResMayNotAlias flag (0x20000000) should not be set at all.
+
 target triple = "dxil-pc-shadermodel6.6-library"
 
 ; CHECK:      Combined Shader Flags for Module

llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.7.ll

@@ -1,5 +1,10 @@
 ; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
 
+; This test checks to ensure the behavior of the DXIL shader flag analysis
+; for the flag ResMayNotAlias is correct when the DXIL Version is 1.7. The
+; ResMayNotAlias flag (0x20000000) should be set on all functions if there are
+; one or more UAVs present globally in the module.
+
 target triple = "dxil-pc-shadermodel6.7-library"
 
 ; CHECK:      Combined Shader Flags for Module

llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.8.ll

@@ -1,5 +1,10 @@
 ; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
 
+; This test checks to ensure the behavior of the DXIL shader flag analysis
+; for the flag ResMayNotAlias is correct when the DXIL Version is 1.8. The
+; ResMayNotAlias flag (0x20000000) should only be set when a function uses a
+; UAV.
+
 target triple = "dxil-pc-shadermodel6.8-library"
 
 ; CHECK:      Combined Shader Flags for Module