AMDGPU/SI: Fix crash when inline assembly is used in a graphics shader

[nhaehnle]

Summary

This is admittedly something that you could only run into by manually
playing around with shader assembly because the SITypeWriter pass is
skipped for compute.

[nhaehnle]

Actually add the correct test.

[arsenm]

LGTM

llvm/trunk/lib/Target/AMDGPU/SITypeRewriter.cpp

 
 void SITypeRewriter::visitCallInst(CallInst &I) {
   IRBuilder<> Builder(&I);
 
   SmallVector <Value*, 8> Args;
   SmallVector <Type*, 8> Types;
   bool NeedToReplace = false;
   Function *F = I.getCalledFunction();
+  if (!F)
+    return;
+
   std::string Name = F->getName();
   for (unsigned i = 0, e = I.getNumArgOperands(); i != e; ++i) {
     Value *Arg = I.getArgOperand(i);
     if (Arg->getType() == v16i8) {
       Args.push_back(Builder.CreateBitCast(Arg, v4i32));
       Types.push_back(v4i32);
       NeedToReplace = true;
       Name = Name + ".v4i32";

llvm/trunk/test/CodeGen/AMDGPU/inline-asm.ll

 ; RUN: llc < %s -march=amdgcn -mcpu=SI -verify-machineinstrs | FileCheck %s
 ; RUN: llc < %s -march=amdgcn -mcpu=tonga -verify-machineinstrs | FileCheck %s
 
 ; CHECK: {{^}}inline_asm:
 ; CHECK: s_endpgm
 ; CHECK: s_endpgm
 define void @inline_asm(i32 addrspace(1)* %out) {
 entry:
   store i32 5, i32 addrspace(1)* %out
   call void asm sideeffect "s_endpgm", ""()
   ret void
 }
+
+; CHECK: {{^}}inline_asm_shader:
+; CHECK: s_endpgm
+; CHECK: s_endpgm
+define void @inline_asm_shader() #0 {
+entry:
+  call void asm sideeffect "s_endpgm", ""()
+  ret void
+}
+
+attributes #0 = { "ShaderType"="0" }