Remove dyn_cast + dereference pattern by replacing it with a cast and changing

the safety check to look for the same type we're going to actually cast to.
Fixes PR13180!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159110 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 21 insertions, 3 deletions

diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 3d4d50a..58a8b35 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -129,7 +129,7 @@ static bool SafeToMergeTerminators(TerminatorInst *SI1, TerminatorInst *SI2) {
 ///
 static bool isProfitableToFoldUnconditional(BranchInst *SI1,
                                           BranchInst *SI2,
-                                          Instruction* Cond,
+                                          Instruction *Cond,
                                           SmallVectorImpl<PHINode*> &PhiNodes) {
   if (SI1 == SI2) return false;  // Can't merge with self!
   assert(SI1->isUnconditional() && SI2->isConditional());
@@ -156,7 +156,7 @@ static bool isProfitableToFoldUnconditional(BranchInst *SI1,
            isa<PHINode>(BBI); ++BBI) {
         PHINode *PN = cast<PHINode>(BBI);
         if (PN->getIncomingValueForBlock(SI1BB) != Cond ||
-            !isa<Constant>(PN->getIncomingValueForBlock(SI2BB)))
+            !isa<ConstantInt>(PN->getIncomingValueForBlock(SI2BB)))
           return false;
         PhiNodes.push_back(PN);
       }
@@ -1782,7 +1782,7 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI) {
     } else {
       // Update PHI nodes in the common successors.
       for (unsigned i = 0, e = PHIs.size(); i != e; ++i) {
-        ConstantInt *PBI_C = dyn_cast<ConstantInt>(
+        ConstantInt *PBI_C = cast<ConstantInt>(
           PHIs[i]->getIncomingValueForBlock(PBI->getParent()));
         assert(PBI_C->getType()->isIntegerTy(1));
         Instruction *MergedCond = 0;
diff --git a/test/Transforms/SimplifyCFG/branch-fold.ll b/test/Transforms/SimplifyCFG/branch-fold.ll
index 70c5fb5..7097dea 100644
--- a/test/Transforms/SimplifyCFG/branch-fold.ll
+++ b/test/Transforms/SimplifyCFG/branch-fold.ll
@@ -50,3 +50,21 @@ c:
   %o2 = phi i1 [ false, %a ], [ %phitmp, %b ], [ false, %entry ]
   ret i1 %o2
 }
+
+; PR13180
+define void @pr13180(i8 %p) {
+entry:
+  %tobool = icmp eq i8 %p, 0
+  br i1 %tobool, label %cond.false, label %cond.true
+
+cond.true:                                        ; preds = %entry
+  br label %cond.end
+
+cond.false:                                       ; preds = %entry
+  %phitmp = icmp eq i8 %p, 0
+  br label %cond.end
+
+cond.end:                                         ; preds = %cond.false, %cond.true
+  %cond = phi i1 [ undef, %cond.true ], [ %phitmp, %cond.false ]
+  unreachable
+}