2 files changed, 27 insertions, 21 deletions
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyCFGSort.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyCFGSort.cpp
index 98bdfafef52..4c5d0192fc2 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyCFGSort.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyCFGSort.cpp
@@ -34,6 +34,14 @@ using namespace llvm;
 
 #define DEBUG_TYPE "wasm-cfg-sort"
 
+// Option to disable EH pad first sorting. Only for testing unwind destination
+// mismatches in CFGStackify.
+static cl::opt<bool> WasmDisableEHPadSort(
+    "wasm-disable-ehpad-sort", cl::ReallyHidden,
+    cl::desc(
+        "WebAssembly: Disable EH pad-first sort order. Testing purpose only."),
+    cl::init(false));
+
 namespace {
 
 // Wrapper for loops and exceptions
@@ -187,10 +195,12 @@ namespace {
 struct CompareBlockNumbers {
   bool operator()(const MachineBasicBlock *A,
                   const MachineBasicBlock *B) const {
-    if (A->isEHPad() && !B->isEHPad())
-      return false;
-    if (!A->isEHPad() && B->isEHPad())
-      return true;
+    if (!WasmDisableEHPadSort) {
+      if (A->isEHPad() && !B->isEHPad())
+        return false;
+      if (!A->isEHPad() && B->isEHPad())
+        return true;
+    }
 
     return A->getNumber() > B->getNumber();
   }
@@ -199,11 +209,12 @@ struct CompareBlockNumbers {
 struct CompareBlockNumbersBackwards {
   bool operator()(const MachineBasicBlock *A,
                   const MachineBasicBlock *B) const {
-    // We give a higher priority to an EH pad
-    if (A->isEHPad() && !B->isEHPad())
-      return false;
-    if (!A->isEHPad() && B->isEHPad())
-      return true;
+    if (!WasmDisableEHPadSort) {
+      if (A->isEHPad() && !B->isEHPad())
+        return false;
+      if (!A->isEHPad() && B->isEHPad())
+        return true;
+    }
 
     return A->getNumber() < B->getNumber();
   }
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
index a7c120963e0..3f5aba087f0 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
@@ -101,6 +101,13 @@ bool WebAssemblyInstrInfo::analyzeBranch(MachineBasicBlock &MBB,
                                          MachineBasicBlock *&FBB,
                                          SmallVectorImpl<MachineOperand> &Cond,
                                          bool /*AllowModify*/) const {
+  const auto &MFI = *MBB.getParent()->getInfo<WebAssemblyFunctionInfo>();
+  // WebAssembly has control flow that doesn't have explicit branches or direct
+  // fallthrough (e.g. try/catch), which can't be modeled by analyzeBranch. It
+  // is created after CFGStackify.
+  if (MFI.isCFGStackified())
+    return true;
+
   bool HaveCond = false;
   for (MachineInstr &MI : MBB.terminators()) {
     switch (MI.getOpcode()) {
@@ -110,9 +117,6 @@ bool WebAssemblyInstrInfo::analyzeBranch(MachineBasicBlock &MBB,
     case WebAssembly::BR_IF:
       if (HaveCond)
         return true;
-      // If we're running after CFGStackify, we can't optimize further.
-      if (!MI.getOperand(0).isMBB())
-        return true;
       Cond.push_back(MachineOperand::CreateImm(true));
       Cond.push_back(MI.getOperand(1));
       TBB = MI.getOperand(0).getMBB();
@@ -121,18 +125,12 @@ bool WebAssemblyInstrInfo::analyzeBranch(MachineBasicBlock &MBB,
     case WebAssembly::BR_UNLESS:
       if (HaveCond)
         return true;
-      // If we're running after CFGStackify, we can't optimize further.
-      if (!MI.getOperand(0).isMBB())
-        return true;
       Cond.push_back(MachineOperand::CreateImm(false));
       Cond.push_back(MI.getOperand(1));
       TBB = MI.getOperand(0).getMBB();
       HaveCond = true;
       break;
     case WebAssembly::BR:
-      // If we're running after CFGStackify, we can't optimize further.
-      if (!MI.getOperand(0).isMBB())
-        return true;
       if (!HaveCond)
         TBB = MI.getOperand(0).getMBB();
       else
@@ -141,9 +139,6 @@ bool WebAssemblyInstrInfo::analyzeBranch(MachineBasicBlock &MBB,
     case WebAssembly::BR_ON_EXN:
       if (HaveCond)
         return true;
-      // If we're running after CFGStackify, we can't optimize further.
-      if (!MI.getOperand(0).isMBB())
-        return true;
       Cond.push_back(MachineOperand::CreateImm(true));
       Cond.push_back(MI.getOperand(2));
       TBB = MI.getOperand(0).getMBB();