[SandboxVec] Early return checks

This patch implements a couple of early return checks.

Author: vporpo

llvm/lib/Transforms/Vectorize/SandboxVectorizer/SandboxVectorizer.cpp

@@ -29,7 +29,18 @@ PreservedAnalyses SandboxVectorizerPass::run(Function &F,
 }
 
 bool SandboxVectorizerPass::runImpl(Function &F) {
+  // If the target claims to have no vector registers early return.
+  if (!TTI->getNumberOfRegisters(TTI->getRegisterClassForType(true))) {
+    LLVM_DEBUG(dbgs() << "SBVec: Target has no vector registers, return.\n");
+    return false;
+  }
   LLVM_DEBUG(dbgs() << "SBVec: Analyzing " << F.getName() << ".\n");
+  // Don't vectorize when the attribute NoImplicitFloat is used.
+  if (F.hasFnAttribute(Attribute::NoImplicitFloat)) {
+    LLVM_DEBUG(dbgs() << "SBVec: NoImplicitFloat attribute, return.\n");
+    return false;
+  }
+
   sandboxir::Context Ctx(F.getContext());
   // Create SandboxIR for `F`.
   sandboxir::Function &SBF = *Ctx.createFunction(&F);

llvm/test/Transforms/SandboxVectorizer/X86/no_vector_regs.ll

@@ -0,0 +1,9 @@
+; RUN: opt -passes=sandbox-vectorizer -debug -mtriple=x86_64-- -mattr=-sse %s 2>&1 | FileCheck %s
+; REQUIRES: asserts
+; Please note that this won't update automatically with update_test_checks.py !
+
+; Check that we early return if the target has no vector registers.
+define void @no_vector_regs() {
+; CHECK: SBVec: Target has no vector registers, return.
+  ret void
+}

llvm/test/Transforms/SandboxVectorizer/no_implicit_float.ll

@@ -0,0 +1,9 @@
+; RUN: opt -passes=sandbox-vectorizer -debug %s 2>&1 | FileCheck %s
+; REQUIRES: asserts
+; Please note that this won't update automatically with update_test_checks.py !
+
+; Check that we early return if the function has the NoImplicitFloat attribute.
+define void @no_implicit_float() noimplicitfloat {
+; CHECK: SBVec: NoImplicitFloat attribute, return.
+  ret void
+}