Recognize more non-fallthrough cases in switch/case

src/compiler/translator/RemoveSwitchFallThrough.cpp

@@ -203,12 +203,29 @@ bool RemoveSwitchFallThroughTraverser::visitAggregate(Visit, TIntermAggregate *n
     return false;
 }
 
+bool DoesBlockAlwaysBreak(TIntermBlock *node)
+{
+    if (node->getSequence()->empty())
+    {
+        return false;
+    }
+
+    TIntermBlock *lastStatementAsBlock = node->getSequence()->back()->getAsBlock();
+    if (lastStatementAsBlock)
+    {
+        return DoesBlockAlwaysBreak(lastStatementAsBlock);
+    }
+
+    TIntermBranch *lastStatementAsBranch = node->getSequence()->back()->getAsBranchNode();
+    return lastStatementAsBranch != nullptr;
+}
+
 bool RemoveSwitchFallThroughTraverser::visitBlock(Visit, TIntermBlock *node)
 {
     if (node != mStatementList)
     {
         mPreviousCase->getSequence()->push_back(node);
-        mLastStatementWasBreak = false;
+        mLastStatementWasBreak = DoesBlockAlwaysBreak(node);
         return false;
     }
     return true;

src/tests/gl_tests/GLSLTest.cpp

@@ -3580,6 +3580,48 @@ TEST_P(GLSLTest_ES3, SwitchFinalCaseHasEmptyDeclaration)
     ANGLE_GL_PROGRAM(program, mSimpleVSSource, fragmentShader);
 }
 
+// Test switch/case where break/return statements are within blocks.
+TEST_P(GLSLTest_ES3, SwitchBreakOrReturnInsideBlocks)
+{
+    const std::string &fragmentShader =
+        R"(#version 300 es
+
+        precision highp float;
+
+        uniform int u_zero;
+        out vec4 my_FragColor;
+
+        bool test(int n)
+        {
+            switch(n) {
+                case 0:
+                {
+                    {
+                        break;
+                    }
+                }
+                case 1:
+                {
+                    return true;
+                }
+                case 2:
+                {
+                    n++;
+                }
+            }
+            return false;
+        }
+
+        void main()
+        {
+            my_FragColor = test(u_zero + 1) ? vec4(0, 1, 0, 1) : vec4(1, 0, 0, 1);
+        })";
+
+    ANGLE_GL_PROGRAM(program, mSimpleVSSource, fragmentShader);
+    drawQuad(program.get(), "inputAttribute", 0.5f);
+    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
+}
+
 // Use this to select which configurations (e.g. which renderer, which GLES major version) these tests should be run against.
 ANGLE_INSTANTIATE_TEST(GLSLTest,
                        ES2_D3D9(),