From 49a766e46885570266a06b6bf8fbd5ee31783d8a Mon Sep 17 00:00:00 2001
From: Jingyue Wu <jingyue@google.com>
Date: Mon, 2 Feb 2015 20:41:11 +0000
Subject: [PATCH] Resurrect the assertion removed by r227717

Summary: MSVC can compile "LoopID->getOperand(0) == LoopID" when LoopID is MDNode*.

Test Plan: no regression

Reviewers: mkuper

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D7327

llvm-svn: 227853
---
 llvm/include/llvm/Transforms/Utils/UnrollLoop.h |  2 +-
 llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp       |  3 +--
 llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp   | 11 +++++------
 llvm/lib/Transforms/Utils/LoopUnroll.cpp        |  7 ++++---
 4 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/llvm/include/llvm/Transforms/Utils/UnrollLoop.h b/llvm/include/llvm/Transforms/Utils/UnrollLoop.h
index 25a32d0..04d9ee1 100644
--- a/llvm/include/llvm/Transforms/Utils/UnrollLoop.h
+++ b/llvm/include/llvm/Transforms/Utils/UnrollLoop.h
@@ -34,7 +34,7 @@ bool UnrollLoop(Loop *L, unsigned Count, unsigned TripCount, bool AllowRuntime,
 bool UnrollRuntimeLoopProlog(Loop *L, unsigned Count, LoopInfo *LI,
                              LPPassManager* LPM);
 
-const MDNode *GetUnrollMetadata(const MDNode *LoopID, StringRef Name);
+MDNode *GetUnrollMetadata(MDNode *LoopID, StringRef Name);
 }
 
 #endif
diff --git a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
index 92e5a58..93f82b2 100644
--- a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -442,8 +442,7 @@ bool NVPTXAsmPrinter::isLoopHeaderOfNoUnroll(
       continue;
     }
     if (const BasicBlock *PBB = PMBB->getBasicBlock()) {
-      if (const MDNode *LoopID =
-              PBB->getTerminator()->getMetadata("llvm.loop")) {
+      if (MDNode *LoopID = PBB->getTerminator()->getMetadata("llvm.loop")) {
         if (GetUnrollMetadata(LoopID, "llvm.loop.unroll.disable"))
           return true;
       }
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index 9a5f088..2c7f55d 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -231,11 +231,10 @@ static unsigned ApproximateLoopSize(const Loop *L, unsigned &NumCalls,
 // Returns the loop hint metadata node with the given name (for example,
 // "llvm.loop.unroll.count").  If no such metadata node exists, then nullptr is
 // returned.
-static const MDNode *GetUnrollMetadataForLoop(const Loop *L, StringRef Name) {
-  MDNode *LoopID = L->getLoopID();
-  if (!LoopID)
-    return nullptr;
-  return GetUnrollMetadata(LoopID, Name);
+static MDNode *GetUnrollMetadataForLoop(const Loop *L, StringRef Name) {
+  if (MDNode *LoopID = L->getLoopID())
+    return GetUnrollMetadata(LoopID, Name);
+  return nullptr;
 }
 
 // Returns true if the loop has an unroll(full) pragma.
@@ -251,7 +250,7 @@ static bool HasUnrollDisablePragma(const Loop *L) {
 // If loop has an unroll_count pragma return the (necessarily
 // positive) value from the pragma.  Otherwise return 0.
 static unsigned UnrollCountPragmaValue(const Loop *L) {
-  const MDNode *MD = GetUnrollMetadataForLoop(L, "llvm.loop.unroll.count");
+  MDNode *MD = GetUnrollMetadataForLoop(L, "llvm.loop.unroll.count");
   if (MD) {
     assert(MD->getNumOperands() == 2 &&
            "Unroll count hint metadata should have two operands.");
diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index 0ee2fee..accb731 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -553,16 +553,17 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
 /// Given an llvm.loop loop id metadata node, returns the loop hint metadata
 /// node with the given name (for example, "llvm.loop.unroll.count"). If no
 /// such metadata node exists, then nullptr is returned.
-const MDNode *llvm::GetUnrollMetadata(const MDNode *LoopID, StringRef Name) {
+MDNode *llvm::GetUnrollMetadata(MDNode *LoopID, StringRef Name) {
   // First operand should refer to the loop id itself.
   assert(LoopID->getNumOperands() > 0 && "requires at least one operand");
+  assert(LoopID->getOperand(0) == LoopID && "invalid loop id");
 
   for (unsigned i = 1, e = LoopID->getNumOperands(); i < e; ++i) {
-    const MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
+    MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
     if (!MD)
       continue;
 
-    const MDString *S = dyn_cast<MDString>(MD->getOperand(0));
+    MDString *S = dyn_cast<MDString>(MD->getOperand(0));
     if (!S)
       continue;
 
-- 
2.7.4