Test for and prevent any dead-code elimination, as all code is needed in the AST…

Test/baseResults/dce.frag.out

+0:? Sequence
+0:5  Sequence
+0:5    move second child to first child (int)
+0:5      'c' (int)
+0:5      0 (const int)
+0:7  Function Definition: bar( (void)
+0:7    Function Parameters: 
+0:9    Sequence
+0:9      Test condition and select (void)
+0:9        Condition
+0:9        false (const bool)
+0:9        true case
+0:10        Pre-Increment (int)
+0:10          'c' (int)
+0:9        false case
+0:12        Pre-Increment (int)
+0:12          'c' (int)
+0:14      Test condition and select (int)
+0:14        Condition
+0:14        false (const bool)
+0:14        true case
+0:14        Pre-Increment (int)
+0:14          'c' (int)
+0:14        false case
+0:14        Pre-Increment (int)
+0:14          'c' (int)
+0:16      switch
+0:16      condition
+0:16        'c' (int)
+0:16      body
+0:16        Sequence
+0:17          case:  with expression
+0:17            1 (const int)
+0:?           Sequence
+0:18            Pre-Increment (int)
+0:18              'c' (int)
+0:19            Branch: Break
+0:20            Pre-Increment (int)
+0:20              'c' (int)
+0:21          case:  with expression
+0:21            2 (const int)
+0:?           Sequence
+0:22            Branch: Break
+0:23            Pre-Increment (int)
+0:23              'c' (int)
+0:24          default: 
+0:?           Sequence
+0:25            Branch: Break
+0:28      Sequence
+0:28        Sequence
+0:28          move second child to first child (int)
+0:28            'i' (int)
+0:28            0 (const int)
+0:28        Loop with condition tested first
+0:28          Loop Condition
+0:28          Compare Less Than (bool)
+0:28            'i' (int)
+0:28            0 (const int)
+0:28          Loop Body
+0:29          Pre-Increment (int)
+0:29            'c' (int)
+0:28          Loop Terminal Expression
+0:28          Pre-Increment (int)
+0:28            'i' (int)
+0:31      Sequence
+0:31        Sequence
+0:31          move second child to first child (int)
+0:31            'i' (int)
+0:31            0 (const int)
+0:31        Loop with condition tested first
+0:31          Loop Condition
+0:31          Compare Less Than (bool)
+0:31            'i' (int)
+0:31            10 (const int)
+0:31          Loop Body
+0:32          Sequence
+0:32            Test condition and select (void)
+0:32              Condition
+0:32              Compare Less Than (bool)
+0:32                'c' (int)
+0:32                3 (const int)
+0:32              true case
+0:33              Sequence
+0:33                Branch: Break
+0:34                Pre-Increment (int)
+0:34                  'c' (int)
+0:32              false case
+0:36              Sequence
+0:36                Branch: Continue
+0:37                Pre-Increment (int)
+0:37                  'c' (int)
+0:31          Loop Terminal Expression
+0:31          Pre-Increment (int)
+0:31            'i' (int)
+0:41      Branch: Return
+0:43      Pre-Increment (int)
+0:43        'c' (int)
+0:46  Function Definition: foo( (int)
+0:46    Function Parameters: 
+0:48    Sequence
+0:48      Test condition and select (void)
+0:48        Condition
+0:48        Compare Greater Than (bool)
+0:48          'c' (int)
+0:48          4 (const int)
+0:48        true case
+0:49        Sequence
+0:49          Branch: Return with expression
+0:49            4 (const int)
+0:50          Pre-Increment (int)
+0:50            'c' (int)
+0:53      Branch: Return with expression
+0:53        5 (const int)
+0:55      Pre-Increment (int)
+0:55        'c' (int)
+

Test/baseResults/precision.frag.out

@@ -55,11 +55,15 @@ ERROR: node is still EOpNull!
 0:58          Loop Condition
 0:58          true (const bool)
 0:58          Loop Body
-0:?           Sequence
-0:?             Sequence
-0:54              add second child into first child (mediump int)
-0:54                'sum' (lowp int)
-0:54                'level4_medium' (mediump int)
+0:51          Sequence
+0:51            Test condition and select (void)
+0:51              Condition
+0:51              true (const bool)
+0:51              true case
+0:?               Sequence
+0:54                add second child into first child (mediump int)
+0:54                  'sum' (lowp int)
+0:54                  'level4_medium' (mediump int)
 0:57            add second child into first child (highp int)
 0:57              'sum' (lowp int)
 0:57              'level3_high' (highp int)

Test/baseResults/uint.frag.out

@@ -25,18 +25,48 @@ ERROR: node is still EOpNull!
 0:19              't' (flat in mediump 2-component vector of uint)
 0:19              1 (const int)
 0:19            3 (const uint)
-0:28      multiply second child into first child (mediump int)
-0:28        'count' (mediump int)
-0:28        2 (const int)
-0:30      multiply second child into first child (mediump int)
-0:30        'count' (mediump int)
-0:30        3 (const int)
-0:42      multiply second child into first child (mediump int)
-0:42        'count' (mediump int)
-0:42        7 (const int)
-0:44      multiply second child into first child (mediump int)
-0:44        'count' (mediump int)
-0:44        11 (const int)
+0:27      Test condition and select (void)
+0:27        Condition
+0:27        true (const bool)
+0:27        true case
+0:28        multiply second child into first child (mediump int)
+0:28          'count' (mediump int)
+0:28          2 (const int)
+0:29      Test condition and select (void)
+0:29        Condition
+0:29        true (const bool)
+0:29        true case
+0:30        multiply second child into first child (mediump int)
+0:30          'count' (mediump int)
+0:30          3 (const int)
+0:31      Test condition and select (void)
+0:31        Condition
+0:31        false (const bool)
+0:31        true case
+0:32        multiply second child into first child (mediump int)
+0:32          'count' (mediump int)
+0:32          5 (const int)
+0:41      Test condition and select (void)
+0:41        Condition
+0:41        true (const bool)
+0:41        true case
+0:42        multiply second child into first child (mediump int)
+0:42          'count' (mediump int)
+0:42          7 (const int)
+0:43      Test condition and select (void)
+0:43        Condition
+0:43        true (const bool)
+0:43        true case
+0:44        multiply second child into first child (mediump int)
+0:44          'count' (mediump int)
+0:44          11 (const int)
+0:45      Test condition and select (void)
+0:45        Condition
+0:45        false (const bool)
+0:45        true case
+0:46        multiply second child into first child (mediump int)
+0:46          'count' (mediump int)
+0:46          13 (const int)
 0:49      Sequence
 0:49        move second child to first child (mediump int)
 0:49          'shiftedii' (mediump int)
@@ -127,15 +157,34 @@ ERROR: node is still EOpNull!
 0:67                'ai' (mediump int)
 0:67              Convert int to uint (mediump uint)
 0:67                'count' (mediump int)
-0:76      multiply second child into first child (mediump int)
-0:76        'count' (mediump int)
-0:76        17 (const int)
-0:82      multiply second child into first child (mediump int)
-0:82        'count' (mediump int)
-0:82        23 (const int)
-0:85      multiply second child into first child (mediump int)
-0:85        'count' (mediump int)
-0:85        27 (const int)
+0:75      Test condition and select (void)
+0:75        Condition
+0:75        true (const bool)
+0:75        true case
+0:76        multiply second child into first child (mediump int)
+0:76          'count' (mediump int)
+0:76          17 (const int)
+0:78      Test condition and select (void)
+0:78        Condition
+0:78        false (const bool)
+0:78        true case
+0:79        multiply second child into first child (mediump int)
+0:79          'count' (mediump int)
+0:79          19 (const int)
+0:81      Test condition and select (void)
+0:81        Condition
+0:81        true (const bool)
+0:81        true case
+0:82        multiply second child into first child (mediump int)
+0:82          'count' (mediump int)
+0:82          23 (const int)
+0:84      Test condition and select (void)
+0:84        Condition
+0:84        true (const bool)
+0:84        true case
+0:85        multiply second child into first child (mediump int)
+0:85          'count' (mediump int)
+0:85          27 (const int)
 0:87      Sequence
 0:87        move second child to first child (mediump uint)
 0:87          'mask1' (mediump uint)

Test/dce.frag

+#version 400
+
+const bool flag = false;
+
+int c = 0;
+
+void bar()
+{
+    if (flag)
+        ++c;  // should still show up in AST
+    else
+        ++c;
+
+    flag ? ++c : ++c;  // both should still show up in AST
+
+    switch (c) {
+    case 1:
+        ++c;
+        break;
+        ++c;  // should still show up in AST
+    case 2:
+        break;
+        ++c;  // should still show up in AST
+    default:
+        break;
+    }
+
+    for (int i = 0; i < 0; ++i)
+        ++c;  // should still show up in AST
+
+    for (int i = 0; i < 10; ++i) {
+        if (c < 3) {
+            break; 
+            ++c;    // should still show up in AST
+        } else {
+            continue;
+            ++c;    // should still show up in AST
+        }
+    }
+
+    return;
+
+    ++c;      // should still show up in AST
+}
+
+int foo()     // not called, but should still show up in AST
+{
+    if (c > 4) {
+        return 4;
+        ++c;   // should still show up in AST
+    }
+
+    return 5;
+
+    ++c;       // should still show up in AST
+}

Test/testlist

@@ -49,6 +49,7 @@ numeral.frag
 400.tese
 420.tese
 430.comp
+dce.frag
 ../../LunarGLASS/test/aggOps.frag
 ../../LunarGLASS/test/always-discard.frag
 ../../LunarGLASS/test/always-discard2.frag

Todo.txt

@@ -3,7 +3,7 @@ Current functionality level: ESSL 3.0
 Link Validation
     + provide input config file for setting limits
 	  - also consider spitting out measures of complexity
-    - ensure no static references thrown away
+    + ensure no static references thrown away
     Cross-stage linking
       - type consistency check of uniform and ins <-> outs, both variables and blocks, stage-specific arrayness matching
       - location/binding/index check

glslang/MachineIndependent/Intermediate.cpp

@@ -688,16 +688,9 @@ TIntermAggregate* TIntermediate::makeAggregate(TIntermNode* node, TSourceLoc loc
 TIntermNode* TIntermediate::addSelection(TIntermTyped* cond, TIntermNodePair nodePair, TSourceLoc loc)
 {
     //
-    // For compile time constant selections, prune the code and 
-    // test now.
+    // Don't prune the false path for compile-time constants; it's needed
+    // for static access analysis.
     //
-    
-    if (cond->getAsTyped() && cond->getAsTyped()->getAsConstantUnion()) {
-        if (cond->getAsTyped()->getAsConstantUnion()->getUnionArrayPointer()->getBConst())
-            return nodePair.node1;
-        else
-            return nodePair.node2;
-    }
 
     TIntermSelection* node = new TIntermSelection(cond, nodePair.node1, nodePair.node2);
     node->setLoc(loc);