[Driver][VE] Change to enable VPU flag by default

Change to enable VPU flag for VE by default in order to support vector
intrinsics from clang.

Reviewed By: efocht, MaskRay

Differential Revision: https://reviews.llvm.org/D157813

clang/include/clang/Driver/Options.td

@@ -199,6 +199,8 @@ def m_x86_Features_Group : OptionGroup<"<x86 features group>">,
                            DocName<"X86">;
 def m_riscv_Features_Group : OptionGroup<"<riscv features group>">,
                              Group<m_Group>, DocName<"RISC-V">;
+def m_ve_Features_Group : OptionGroup<"<ve features group>">,
+                          Group<m_Group>, DocName<"VE">;
 
 def m_libc_Group : OptionGroup<"<m libc group>">, Group<m_mips_Features_Group>,
                    Flags<[HelpHidden]>;
@@ -5845,6 +5847,13 @@ def mno_scatter : Flag<["-"], "mno-scatter">, Group<m_x86_Features_Group>,
                   HelpText<"Disable generation of scatter instructions in auto-vectorization(x86 only)">;
 } // let Flags = [TargetSpecific]
 
+// VE feature flags
+let Flags = [TargetSpecific] in {
+def mvevpu : Flag<["-"], "mvevpu">, Group<m_ve_Features_Group>,
+  HelpText<"Emit VPU instructions for VE">;
+def mno_vevpu : Flag<["-"], "mno-vevpu">, Group<m_ve_Features_Group>;
+} // let Flags = [TargetSpecific]
+
 // These are legacy user-facing driver-level option spellings. They are always
 // aliases for options that are spelled using the more common Unix / GNU flag
 // style of double-dash and equals-joined flags.

clang/lib/Driver/ToolChains/Arch/VE.cpp

@@ -18,4 +18,9 @@ using namespace clang;
 using namespace llvm::opt;
 
 void ve::getVETargetFeatures(const Driver &D, const ArgList &Args,
-                             std::vector<StringRef> &Features) {}
+                             std::vector<StringRef> &Features) {
+  if (Args.hasFlag(options::OPT_mvevpu, options::OPT_mno_vevpu, true))
+    Features.push_back("+vpu");
+  else
+    Features.push_back("-vpu");
+}

clang/test/Driver/ve-features.c

@@ -0,0 +1,5 @@
+// RUN: %clang --target=ve-unknown-linux-gnu -### %s 2>&1 | FileCheck %s -check-prefix=DEFAULT
+// RUN: %clang --target=ve-unknown-linux-gnu -### %s -mvevpu -mno-vevpu 2>&1 | FileCheck %s -check-prefix=NO-VEVPU
+
+// DEFAULT: "-target-feature" "+vpu"
+// NO-VEVPU: "-target-feature" "-vpu"