AMDGPU: Add support for 's' and 'v' asm constraints

[• tstellarAMD]

Summary

's' is used to specify sgprs and 'v' is used to specify vgprs.

[echristo]

Sure. You should probably work on the verification side of things as well if you expect to use this more.

-eric

lib/Basic/Targets.cpp

public:
 
   ArrayRef<const char *> getGCCRegNames() const override;
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
     return None;
   }
 
   bool validateAsmConstraint(const char *&Name,
-                             TargetInfo::ConstraintInfo &info) const override {
+                             TargetInfo::ConstraintInfo &Info) const override {
+    switch (*Name) {
+    default: break;
+    case 'v': // vgpr
+    case 's': // sgpr
+      Info.setAllowsRegister();
       return true;
     }
+    return false;
+  }
 
   ArrayRef<Builtin::Info> getTargetBuiltins() const override {
     return llvm::makeArrayRef(BuiltinInfo,
                         clang::AMDGPU::LastTSBuiltin - Builtin::FirstTSBuiltin);
   }
 
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override {

test/Sema/inline-asm-validate-amdgpu.cl

+// REQUIRES: amdgpu-registered-target
+// RUN: %clang_cc1 -x cl -triple amdgcn -fsyntax-only  %s
+// expected-no-diagnostics
+
+kernel void test () {
+
+  int sgpr = 0, vgpr = 0, imm = 0;
+
+  // sgpr constraints
+  __asm__ ("s_mov_b32 %0, %1" : "=s" (sgpr) : "s" (imm) : );
+
+  // vgpr constraints
+  __asm__ ("v_mov_b32 %0, %1" : "=v" (vgpr) : "v" (imm) : );
+}