[SandboxVec] Add BottomUpVec test flag to build regions from metadata.

llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Passes/PrintInstructionCountPass.h

@@ -0,0 +1,24 @@
+#ifndef LLVM_TRANSFORMS_VECTORIZE_SANDBOXVECTORIZER_PASSES_PRINTINSTRUCTIONCOUNTPASS_H
+#define LLVM_TRANSFORMS_VECTORIZE_SANDBOXVECTORIZER_PASSES_PRINTINSTRUCTIONCOUNTPASS_H
+
+#include "llvm/SandboxIR/Pass.h"
+
+namespace llvm::sandboxir {
+
+class Region;
+
+/// A Region pass that prints the instruction count for the region to stdout.
+/// Used to test -sbvec-passes while we don't have any actual optimization
+/// passes.
+class PrintInstructionCountPass final : public RegionPass {
+public:
+  PrintInstructionCountPass() : RegionPass("null") {}
+  bool runOnRegion(Region &R) final {
+    outs() << "InstructionCount: " << std::distance(R.begin(), R.end()) << "\n";
+    return false;
+  }
+};
+
+} // namespace llvm::sandboxir
+
+#endif // LLVM_TRANSFORMS_VECTORIZE_SANDBOXVECTORIZER_PASSES_PRINTINSTRUCTIONCOUNTPASS_H

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

@@ -10,15 +10,22 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/SandboxIR/Function.h"
 #include "llvm/SandboxIR/Instruction.h"
+#include "llvm/SandboxIR/Region.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/NullPass.h"
+#include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/PrintInstructionCountPass.h"
 
 namespace llvm::sandboxir {
 
 static cl::opt<bool>
     PrintPassPipeline("sbvec-print-pass-pipeline", cl::init(false), cl::Hidden,
                       cl::desc("Prints the pass pipeline and returns."));
 
+static cl::opt<bool> UseRegionsFromMetadata(
+    "sbvec-use-regions-from-metadata", cl::init(false), cl::Hidden,
+    cl::desc("Skips bottom-up vectorization, builds regions from metadata "
+             "already present in the IR and runs the region pass pipeline."));
+
 /// A magic string for the default pass pipeline.
 static const char *DefaultPipelineMagicStr = "*";
 
@@ -86,6 +93,14 @@ bool BottomUpVec::runOnFunction(Function &F) {
     RPM.printPipeline(outs());
     return false;
   }
+  if (UseRegionsFromMetadata) {
+    SmallVector<std::unique_ptr<Region>> Regions =
+        Region::createRegionsFromMD(F);
+    for (auto &R : Regions) {
+      RPM.runOnRegion(*R);
+    }
+    return false;
+  }
 
   Change = false;
   // TODO: Start from innermost BBs first

llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/PassRegistry.def

@@ -18,5 +18,6 @@
 #endif
 
 REGION_PASS("null", NullPass())
+REGION_PASS("print-instruction-count", PrintInstructionCountPass())
 
 #undef REGION_PASS

llvm/test/Transforms/SandboxVectorizer/regions-from-metadata.ll

@@ -0,0 +1,16 @@
+; RUN: opt -disable-output --passes=sandbox-vectorizer \
+; RUN:    -sbvec-passes=print-instruction-count \
+; RUN:    -sbvec-use-regions-from-metadata %s | FileCheck %s
+
+define i8 @foo(i8 %v0, i8 %v1) {
+  %t0 = add i8 %v0, 1, !sandboxvec !0
+  %t1 = add i8 %t0, %v1, !sandboxvec !1
+  %t2 = add i8 %t1, %v1, !sandboxvec !1
+  ret i8 %t2
+}
+
+!0 = distinct !{!"sandboxregion"}
+!1 = distinct !{!"sandboxregion"}
+
+; CHECK: InstructionCount: 1
+; CHECK: InstructionCount: 2