Extend verify pass to cover new metadata

Author: jdenny-ornl

llvm/docs/LangRef.rst

@@ -7950,8 +7950,8 @@ loop distribution pass. See
 
 This metadata records an estimated trip count for the loop.  The first operand
 is the string ``llvm.loop.estimated_trip_count``.  The second operand is an
-integer specifying the count, which might be omitted for the reasons described
-below.  For example:
+integer constant of type ``i32`` or smaller specifying the count, which might be
+omitted for the reasons described below.  For example:
 
 .. code-block:: llvm
 

llvm/include/llvm/IR/Metadata.h

@@ -911,8 +911,8 @@ class MDOperand {
 
   // Check if MDOperand is of type MDString and equals `Str`.
   bool equalsStr(StringRef Str) const {
-    return isa<MDString>(this->get()) &&
-           cast<MDString>(this->get())->getString() == Str;
+    return isa_and_nonnull<MDString>(get()) &&
+           cast<MDString>(get())->getString() == Str;
   }
 
   ~MDOperand() { untrack(); }

llvm/include/llvm/Transforms/Utils/LoopUtils.h

@@ -52,6 +52,8 @@ typedef std::pair<const RuntimeCheckingPtrGroup *,
 template <typename T, unsigned N> class SmallSetVector;
 template <typename T, unsigned N> class SmallPriorityWorklist;
 
+const char *const LLVMLoopEstimatedTripCount = "llvm.loop.estimated_trip_count";
+
 LLVM_ABI BasicBlock *InsertPreheaderForLoop(Loop *L, DominatorTree *DT,
                                             LoopInfo *LI,
                                             MemorySSAUpdater *MSSAU,

llvm/lib/IR/Verifier.cpp

@@ -121,6 +121,7 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/ModRef.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Utils/LoopUtils.h"
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
@@ -1071,6 +1072,21 @@ void Verifier::visitMDNode(const MDNode &MD, AreDebugLocsAllowed AllowLocs) {
     }
   }
 
+  // Check llvm.loop.estimated_trip_count.
+  if (MD.getNumOperands() > 0 &&
+      MD.getOperand(0).equalsStr(LLVMLoopEstimatedTripCount)) {
+    Check(MD.getNumOperands() == 1 || MD.getNumOperands() == 2,
+          "Expected one or two operands", &MD);
+    if (MD.getNumOperands() == 2) {
+      auto *Count = dyn_cast_or_null<ConstantAsMetadata>(MD.getOperand(1));
+      Check(Count && Count->getType()->isIntegerTy() &&
+                cast<IntegerType>(Count->getType())->getBitWidth() <= 32,
+            "Expected optional second operand to be an integer constant of "
+            "type i32 or smaller",
+            &MD);
+    }
+  }
+
   // Check these last, so we diagnose problems in operands first.
   Check(!MD.isTemporary(), "Expected no forward declarations!", &MD);
   Check(MD.isResolved(), "All nodes should be resolved!", &MD);

llvm/lib/Transforms/Utils/LoopUtils.cpp

@@ -54,8 +54,6 @@ using namespace llvm::PatternMatch;
 
 static const char *LLVMLoopDisableNonforced = "llvm.loop.disable_nonforced";
 static const char *LLVMLoopDisableLICM = "llvm.licm.disable";
-static const char *LLVMLoopEstimatedTripCount =
-    "llvm.loop.estimated_trip_count";
 
 bool llvm::formDedicatedExitBlocks(Loop *L, DominatorTree *DT, LoopInfo *LI,
                                    MemorySSAUpdater *MSSAU,

llvm/test/Verifier/llvm.loop.estimated_trip_count.ll

@@ -0,0 +1,58 @@
+; Test "llvm.loop.estimated_trip_count" validation
+
+; DEFINE: %{RUN} = opt -passes=verify %t -disable-output 2>&1 | \
+; DEFINE:   FileCheck %s -allow-empty -check-prefix
+
+define void @test() {
+entry:
+  br label %body
+body:
+  br i1 0, label %body, label %exit, !llvm.loop !0
+exit:
+  ret void
+}
+!0 = distinct !{!0, !1}
+
+; GOOD-NOT: {{.}}
+
+;      BAD-VALUE: Expected optional second operand to be an integer constant of type i32 or smaller
+; BAD-VALUE-NEXT: !1 = !{!"llvm.loop.estimated_trip_count",
+
+;      TOO-MANY: Expected one or two operands
+; TOO-MANY-NEXT: !1 = !{!"llvm.loop.estimated_trip_count", i32 5, i32 5}
+
+; No value.
+; RUN: cp %s %t
+; RUN: echo '!1 = !{!"llvm.loop.estimated_trip_count"}' >> %t
+; RUN: %{RUN} GOOD
+
+; i16 value.
+; RUN: cp %s %t
+; RUN: echo '!1 = !{!"llvm.loop.estimated_trip_count", i16 5}' >> %t
+; RUN: %{RUN} GOOD
+
+; i32 value.
+; RUN: cp %s %t
+; RUN: echo '!1 = !{!"llvm.loop.estimated_trip_count", i32 5}' >> %t
+; RUN: %{RUN} GOOD
+
+; i64 value.
+; RUN: cp %s %t
+; RUN: echo '!1 = !{!"llvm.loop.estimated_trip_count", i64 5}' >> %t
+; RUN: not %{RUN} BAD-VALUE
+
+; MDString value.
+; RUN: cp %s %t
+; RUN: echo '!1 = !{!"llvm.loop.estimated_trip_count", !"5"}' >> %t
+; RUN: not %{RUN} BAD-VALUE
+
+; MDNode value.
+; RUN: cp %s %t
+; RUN: echo '!1 = !{!"llvm.loop.estimated_trip_count", !2}' >> %t
+; RUN: echo '!2 = !{i32 5}' >> %t
+; RUN: not %{RUN} BAD-VALUE
+
+; Too many values.
+; RUN: cp %s %t
+; RUN: echo '!1 = !{!"llvm.loop.estimated_trip_count", i32 5, i32 5}' >> %t
+; RUN: not %{RUN} TOO-MANY