[SandboxVec] Early return checks (#107465)

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");
+  // Early return if 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_implicit_float.ll

@@ -0,0 +1,23 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=sandbox-vectorizer -mtriple=x86_64-- -mattr=+avx %s -S | FileCheck %s
+
+; Check that we don't vectorize a NoImplicitFloat function.
+define void @no_implicit_float(ptr %ptr) noimplicitfloat {
+; CHECK-LABEL: define void @no_implicit_float(
+; CHECK-SAME: ptr [[PTR:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:    [[PTR0:%.*]] = getelementptr double, ptr [[PTR]], i32 0
+; CHECK-NEXT:    [[PTR1:%.*]] = getelementptr double, ptr [[PTR]], i32 1
+; CHECK-NEXT:    [[LD0:%.*]] = load double, ptr [[PTR0]], align 8
+; CHECK-NEXT:    [[LD1:%.*]] = load double, ptr [[PTR1]], align 8
+; CHECK-NEXT:    store double [[LD0]], ptr [[PTR0]], align 8
+; CHECK-NEXT:    store double [[LD1]], ptr [[PTR1]], align 8
+; CHECK-NEXT:    ret void
+;
+  %ptr0 = getelementptr double, ptr %ptr, i32 0
+  %ptr1 = getelementptr double, ptr %ptr, i32 1
+  %ld0 = load double, ptr %ptr0
+  %ld1 = load double, ptr %ptr1
+  store double %ld0, ptr %ptr0
+  store double %ld1, ptr %ptr1
+  ret void
+}