[AArch64] Add option -msve-streaming-vector-bits= . (#144611)

This is similar to -msve-vector-bits, but for streaming mode: it
constrains the legal values of "vscale", allowing optimizations based on
that constraint.

This also fixes conversions between SVE vectors and fixed-width vectors
in streaming functions with -msve-vector-bits and
-msve-streaming-vector-bits.

This rejects any use of arm_sve_vector_bits types in streaming
functions; if it becomes relevant, we could add
arm_sve_streaming_vector_bits types in the future.

This doesn't touch the __ARM_FEATURE_SVE_BITS define.

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 0a9e364..9b3200b 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -4620,6 +4620,11 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
     if (StringRef(A->getValue()).getAsInteger(10, VScaleMin) || VScaleMin == 0)
       Diags.Report(diag::err_cc1_unbounded_vscale_min);
   }
+  if (Arg *A = Args.getLastArg(options::OPT_mvscale_streaming_min_EQ)) {
+    unsigned VScaleMin;
+    if (StringRef(A->getValue()).getAsInteger(10, VScaleMin) || VScaleMin == 0)
+      Diags.Report(diag::err_cc1_unbounded_vscale_min);
+  }
 
   if (const Arg *A = Args.getLastArg(OPT_frandomize_layout_seed_file_EQ)) {
     std::ifstream SeedFile(A->getValue(0));