remove more unneeded break and continue statements in relooper

src/relooper/Relooper.cpp

@@ -136,10 +136,6 @@ void Block::Render(bool InLoop) {
 
   bool SetLabel = true; // in some cases it is clear we can avoid setting label, see later
 
-  if (ProcessedBranchesOut.size() == 1 && ProcessedBranchesOut.begin()->second->Type == Branch::Direct) {
-    SetLabel = false;
-  }
-
   // A setting of the label variable (label = x) is necessary if it can
   // cause an impact. The main case is where we set label to x, then elsewhere
   // we check if label is equal to that value, i.e., that label is an entry
@@ -893,14 +889,17 @@ void Relooper::Calculate(Block *Entry) {
         func(Loop->Next); \
       }
 
-    // Find the single block that must be hit in a shape, or NULL if there is more than one
-    Block *FollowNaturalFlow(Shape *S) {
+    // Find the blocks that natural control flow can get us directly to, or through a multiple that we ignore
+    void FollowNaturalFlow(Shape *S, BlockSet &Out) {
       SHAPE_SWITCH(S, {
-        return Simple->Inner;
+        Out.insert(Simple->Inner);
       }, {
-        return NULL;
+        for (BlockShapeMap::iterator iter = Multiple->InnerMap.begin(); iter != Multiple->InnerMap.end(); iter++) {
+          FollowNaturalFlow(iter->second, Out);
+        }
+        FollowNaturalFlow(Multiple->Next, Out);
       }, {
-        return FollowNaturalFlow(Loop->Inner);
+        FollowNaturalFlow(Loop->Inner, Out);
       });
     }
 
@@ -908,7 +907,8 @@ void Relooper::Calculate(Block *Entry) {
     // A flow operation is trivially unneeded if the shape we naturally get to by normal code
     // execution is the same as the flow forces us to.
     void RemoveUnneededFlows(Shape *Root, Shape *Natural=NULL) {
-      Block *NaturalBlock = FollowNaturalFlow(Natural);
+      BlockSet NaturalBlocks;
+      FollowNaturalFlow(Natural, NaturalBlocks);
       Shape *Next = Root;
       while (Next) {
         Root = Next;
@@ -923,7 +923,7 @@ void Relooper::Calculate(Block *Entry) {
             for (BlockBranchMap::iterator iter = Simple->Inner->ProcessedBranchesOut.begin(); iter != Simple->Inner->ProcessedBranchesOut.end(); iter++) {
               Block *Target = iter->first;
               Branch *Details = iter->second;
-              if (Details->Type != Branch::Direct && Target == NaturalBlock) { // note: cannot handle split blocks
+              if (Details->Type != Branch::Direct && NaturalBlocks.find(Target) != NaturalBlocks.end()) { // note: cannot handle split blocks
                 Details->Type = Branch::Direct;
                 if (MultipleShape *Multiple = Shape::IsMultiple(Details->Ancestor)) {
                   Multiple->NeedLoop--;

src/relooper/test.txt

@@ -126,7 +126,6 @@ do {
       break;
     }
     // block D
-    break;
   }
 } while(0);
 if (label == 33) {

src/relooper/test4.txt

@@ -7,7 +7,6 @@ do {
       break;
     }
     //21
-    break;
   } else {
     label = 4;
   }

src/relooper/test_fuzz1.txt

@@ -3,13 +3,10 @@
 print('entry'); var label; var state; var decisions = [4, 1, 7, 2, 6, 6, 8]; var index = 0; function check() { if (index == decisions.length) throw 'HALT'; return decisions[index++] }
 print(5); state = check();
 print(6); state = check();
-do {
-  if (state == 7) {
-    print(7); state = check();
-    label = 3;
-    break;
-  }
-} while(0);
+if (state == 7) {
+  print(7); state = check();
+  label = 3;
+}
 L5: while(1) {
   if (label == 3) {
     label = 0;

src/relooper/test_fuzz5.txt

@@ -3,22 +3,18 @@
 print('entry'); var label; var state; var decisions = [133, 98, 134, 143, 162, 187, 130, 87, 91, 49, 102, 47, 9, 132, 179, 176, 157, 25, 64, 161, 57, 107, 16, 167, 185, 45, 191, 180, 23, 131]; var index = 0; function check() { if (index == decisions.length) throw 'HALT'; return decisions[index++] }
 L1: while(1) {
   print(7); state = check();
-  do {
-    if (state % 3 == 1) {
-      label = 3;
-    } else if (state % 3 == 0) {
-      print(8); state = check();
-      if (state % 2 == 0) {
-        label = 5;
-        break;
-      } else {
-        label = 7;
-        break;
-      }
+  if (state % 3 == 1) {
+    label = 3;
+  } else if (state % 3 == 0) {
+    print(8); state = check();
+    if (state % 2 == 0) {
+      label = 5;
     } else {
-      break L1;
+      label = 7;
     }
-  } while(0);
+  } else {
+    break;
+  }
   while(1) {
     if (label == 3) {
       label = 0;

src/relooper/test_fuzz6.txt

@@ -82,7 +82,6 @@ while(1) {
           print(56); state = check();// ....................................................................................................................................................................................................................
           print(34); state = check();// ..........................................................................................................................................
           label = 74;
-          continue;
         }
         print(62); state = check();// .......................................................................................
       }

tools/shared.py

@@ -295,7 +295,7 @@ def check_node_version():
 # we re-check sanity when the settings are changed)
 # We also re-check sanity and clear the cache when the version changes
 
-EMSCRIPTEN_VERSION = '1.4.6'
+EMSCRIPTEN_VERSION = '1.4.7'
 
 def generate_sanity():
   return EMSCRIPTEN_VERSION + '|' + get_llvm_target()