Scalable Vector IR Type with further LTO fixes

Reintroduces the scalable vector IR type from D32530, after it was reverted
a couple of times due to increasing chromium LTO build times. This latest
incarnation removes the walk over aggregate types from the verifier entirely,
in favor of rejecting scalable vectors in the isValidElementType methods in
ArrayType and StructType. This removes the 70% degradation observed with
the second repro tarball from PR42210.

Reviewers: thakis, hans, rengolin, sdesmalen

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D64079

llvm-svn: 365203

1 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index ab645348c53..085f3bd2999 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -2747,7 +2747,18 @@ bool LLParser::ParseStructBody(SmallVectorImpl<Type*> &Body) {
 ///   Type
 ///     ::= '[' APSINTVAL 'x' Types ']'
 ///     ::= '<' APSINTVAL 'x' Types '>'
+///     ::= '<' 'vscale' 'x' APSINTVAL 'x' Types '>'
 bool LLParser::ParseArrayVectorType(Type *&Result, bool isVector) {
+  bool Scalable = false;
+
+  if (isVector && Lex.getKind() == lltok::kw_vscale) {
+    Lex.Lex(); // consume the 'vscale'
+    if (ParseToken(lltok::kw_x, "expected 'x' after vscale"))
+      return true;
+
+    Scalable = true;
+  }
+
   if (Lex.getKind() != lltok::APSInt || Lex.getAPSIntVal().isSigned() ||
       Lex.getAPSIntVal().getBitWidth() > 64)
     return TokError("expected number in address space");
@@ -2774,7 +2785,7 @@ bool LLParser::ParseArrayVectorType(Type *&Result, bool isVector) {
       return Error(SizeLoc, "size too large for vector");
     if (!VectorType::isValidElementType(EltTy))
       return Error(TypeLoc, "invalid vector element type");
-    Result = VectorType::get(EltTy, unsigned(Size));
+    Result = VectorType::get(EltTy, unsigned(Size), Scalable);
   } else {
     if (!ArrayType::isValidElementType(EltTy))
       return Error(TypeLoc, "invalid array element type");