[AMDGPU] Ported and adopted AMDLibCalls pass

The pass does simplifications of well known AMD library calls. If given -amdgpu-prelink option it works in a pre-link mode which allows to reference new library functions which will be linked in later. In addition it also used to process traditional AMD option -fuse-native which allows to replace some of the functions with their fast native implementations from the library. The necessary glue to pass the prelink option and translate -fuse-native is to be added to the driver. Differential Revision: https://reviews.llvm.org/D36436 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@310731 91177308-0d34-0410-b5e6-96231b3b80d8

Author: rampitec

lib/Target/AMDGPU/AMDGPU.h

@@ -52,6 +52,8 @@ FunctionPass *createSIDebuggerInsertNopsPass();
 FunctionPass *createSIInsertWaitsPass();
 FunctionPass *createSIInsertWaitcntsPass();
 FunctionPass *createSIFixWWMLivenessPass();
+FunctionPass *createAMDGPUSimplifyLibCallsPass();
+FunctionPass *createAMDGPUUseNativeCallsPass();
 FunctionPass *createAMDGPUCodeGenPreparePass();
 FunctionPass *createAMDGPUMachineCFGStructurizerPass();
 FunctionPass *createAMDGPURewriteOutArgumentsPass();
@@ -125,6 +127,12 @@ extern char &SIOptimizeExecMaskingID;
 void initializeSIFixWWMLivenessPass(PassRegistry &);
 extern char &SIFixWWMLivenessID;
 
+void initializeAMDGPUSimplifyLibCallsPass(PassRegistry &);
+extern char &AMDGPUSimplifyLibCallsID;
+
+void initializeAMDGPUUseNativeCallsPass(PassRegistry &);
+extern char &AMDGPUUseNativeCallsID;
+
 // Passes common to R600 and SI
 FunctionPass *createAMDGPUPromoteAlloca();
 void initializeAMDGPUPromoteAllocaPass(PassRegistry&);