[llvm-branch-commits] [llvm] da0fe2a - Filter callbr insts from critical edge splitting

[Hans Wennborg via llvm-branch-commits]

Author: Bill Wendling
Date: 2020-02-21T09:51:47+01:00
New Revision: da0fe2ade369223ebea2dafd411746e854a801f2

URL: https://github.com/llvm/llvm-project/commit/da0fe2ade369223ebea2dafd411746e854a801f2
DIFF: https://github.com/llvm/llvm-project/commit/da0fe2ade369223ebea2dafd411746e854a801f2.diff

LOG: Filter callbr insts from critical edge splitting

Similarly to how splitting predecessors with an indirectbr isn't handled
in the generic way, we also shouldn't split callbrs, for similar
reasons.

(cherry picked from commit 2fe457690da0fc38bc7f9f1d0aee2ba6a6a16ada)

Added: 
    llvm/test/Transforms/LICM/callbr-crash.ll

Modified: 
    llvm/lib/Transforms/Scalar/LICM.cpp
    llvm/lib/Transforms/Utils/BasicBlockUtils.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index 8c33045c2380..eb023d49b0a3 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -1537,7 +1537,8 @@ static bool canSplitPredecessors(PHINode *PN, LoopSafetyInfo *SafetyInfo) {
     return false;
   for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
     BasicBlock *BBPred = *PI;
-    if (isa<IndirectBrInst>(BBPred->getTerminator()))
+    if (isa<IndirectBrInst>(BBPred->getTerminator()) ||
+        isa<CallBrInst>(BBPred->getTerminator()))
       return false;
   }
   return true;

diff  --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index c9eb4abfa21a..9a7379e27ed6 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -505,7 +505,8 @@ llvm::SplitAllCriticalEdges(Function &F,
   unsigned NumBroken = 0;
   for (BasicBlock &BB : F) {
     Instruction *TI = BB.getTerminator();
-    if (TI->getNumSuccessors() > 1 && !isa<IndirectBrInst>(TI))
+    if (TI->getNumSuccessors() > 1 && !isa<IndirectBrInst>(TI) &&
+        !isa<CallBrInst>(TI))
       for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
         if (SplitCriticalEdge(TI, i, Options))
           ++NumBroken;

diff  --git a/llvm/test/Transforms/LICM/callbr-crash.ll b/llvm/test/Transforms/LICM/callbr-crash.ll
new file mode 100644
index 000000000000..e5e7215d5b41
--- /dev/null
+++ b/llvm/test/Transforms/LICM/callbr-crash.ll
@@ -0,0 +1,18 @@
+; RUN: opt -licm -disable-output < %s
+
+define i32 @j() {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %cond.true.i, %entry
+  callbr void asm sideeffect "", "X,~{dirflag},~{fpsr},~{flags}"(i8* blockaddress(@j, %for.end))
+          to label %cond.true.i [label %for.end]
+
+cond.true.i:                                      ; preds = %for.cond
+  %asmresult1.i.i = extractvalue { i8, i32 } zeroinitializer, 1
+  br i1 undef, label %for.end, label %for.cond
+
+for.end:                                          ; preds = %cond.true.i, %for.cond
+  %asmresult1.i.i2 = phi i32 [ %asmresult1.i.i, %cond.true.i ], [ undef, %for.cond ]
+  ret i32 undef
+}