[PowerPC][Altivec][Clang] Check compile-time constant for vec_dst*

[jsji]

Summary

This is follow up of https://reviews.llvm.org/D66699.
We might get ISEL ICE if we call vec_dss with non const 3rd arg.

Cannot select: intrinsic %llvm.ppc.altivec.dst

We should check the constraints in clang and generate better error
messages.

[jsji]

Ping..

[jsji]

Add range check and tests.

[jsji]

Rebase to ToT.

clang/include/clang/Basic/BuiltinsPPC.def

 
 BUILTIN(__builtin_altivec_vcfsx, "V4fV4iIi", "")
 BUILTIN(__builtin_altivec_vcfux, "V4fV4iIi", "")
 BUILTIN(__builtin_altivec_vctsxs, "V4SiV4fIi", "")
 BUILTIN(__builtin_altivec_vctuxs, "V4UiV4fIi", "")
 
 BUILTIN(__builtin_altivec_dss, "vUi", "")
 BUILTIN(__builtin_altivec_dssall, "v", "")
-BUILTIN(__builtin_altivec_dst, "vvC*iUi", "")
-BUILTIN(__builtin_altivec_dstt, "vvC*iUi", "")
-BUILTIN(__builtin_altivec_dstst, "vvC*iUi", "")
-BUILTIN(__builtin_altivec_dststt, "vvC*iUi", "")
+BUILTIN(__builtin_altivec_dst, "vvC*iUIi", "")
+BUILTIN(__builtin_altivec_dstt, "vvC*iUIi", "")
+BUILTIN(__builtin_altivec_dstst, "vvC*iUIi", "")
+BUILTIN(__builtin_altivec_dststt, "vvC*iUIi", "")
 
 BUILTIN(__builtin_altivec_vexptefp, "V4fV4f", "")
 
 BUILTIN(__builtin_altivec_vrfim, "V4fV4f", "")
 
 BUILTIN(__builtin_altivec_lvx, "V4iivC*", "")
 BUILTIN(__builtin_altivec_lvxl, "V4iivC*", "")
 BUILTIN(__builtin_altivec_lvebx, "V16civC*", "")

clang/lib/Sema/SemaChecking.cpp

bool Sema::CheckPPCBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
   case PPC::BI__builtin_tend: i = 0; l = 0; u = 1; break;
   case PPC::BI__builtin_tsr: i = 0; l = 0; u = 7; break;
   case PPC::BI__builtin_tabortwc:
   case PPC::BI__builtin_tabortdc: i = 0; l = 0; u = 31; break;
   case PPC::BI__builtin_tabortwci:
   case PPC::BI__builtin_tabortdci:
     return SemaBuiltinConstantArgRange(TheCall, 0, 0, 31) ||
            SemaBuiltinConstantArgRange(TheCall, 2, 0, 31);
+  case PPC::BI__builtin_altivec_dst:
+  case PPC::BI__builtin_altivec_dstt:
+  case PPC::BI__builtin_altivec_dstst:
+  case PPC::BI__builtin_altivec_dststt:
+    return SemaBuiltinConstantArgRange(TheCall, 2, 0, 3);
   case PPC::BI__builtin_vsx_xxpermdi:
   case PPC::BI__builtin_vsx_xxsldwi:
     return SemaBuiltinVSX(TheCall);
   case PPC::BI__builtin_unpack_vector_int128:
     return SemaVSXCheck(TheCall) ||
            SemaBuiltinConstantArgRange(TheCall, 1, 0, 1);
   case PPC::BI__builtin_pack_vector_int128:
     return SemaVSXCheck(TheCall);

clang/test/CodeGen/builtins-ppc-error.c

 void testVCTUXS(int index) {
   vec_vctuxs(vf, index); //expected-error {{argument to '__builtin_altivec_vctuxs' must be a constant integer}}
 }
 
 void testUnpack128(int index) {
   __builtin_unpack_vector_int128(vsllli, index); //expected-error {{argument to '__builtin_unpack_vector_int128' must be a constant integer}}
   __builtin_unpack_vector_int128(vsllli, 5); //expected-error {{argument value 5 is outside the valid range [0, 1]}}
 }
+
+
+void testDST(int index) {
+  vec_dst(&vsi, index, index); //expected-error {{argument to '__builtin_altivec_dst' must be a constant integer}}
+  vec_dst(&vsi, index, 5); //expected-error {{argument value 5 is outside the valid range [0, 3]}}
+  vec_dstt(&vsi, index, index); //expected-error {{argument to '__builtin_altivec_dstt' must be a constant integer}}
+  vec_dstt(&vsi, index, 5); //expected-error {{argument value 5 is outside the valid range [0, 3]}}
+  vec_dstst(&vsi, index, index); //expected-error {{argument to '__builtin_altivec_dstst' must be a constant integer}}
+  vec_dstst(&vsi, index, 5); //expected-error {{argument value 5 is outside the valid range [0, 3]}}
+  vec_dststt(&vsi, index, index); //expected-error {{argument to '__builtin_altivec_dststt' must be a constant integer}}
+  vec_dststt(&vsi, index, 5); //expected-error {{argument value 5 is outside the valid range [0, 3]}}
+}