commit 3c9eeb979f4b2431e2303d4a74cd1498d474f6a3
author Jamie Madill <jmadill@chromium.org> Mon Nov 04 11:09:26 2013 -0500
committer Jamie Madill <jmadill@chromium.org> Wed Nov 27 16:47:31 2013 +0000
tree 9067860054ba8bdbdd0d466db0bb5a6d91f402fd
parent 5a60b73990beba0ef1b551cbe0a0c5cbf1236949

Disable optimizations for shaders with conditional discard in D3D9, and
only use expanded short-circuiting conditionals for expressions with
potential side-effects.

Conservatively assume aggreate and selection operators have side effects for now.

BUG=
ANGLEBUG=486
R=geofflang@chromium.org, kbr@chromium.org, nicolas@transgaming.com, shannonwoods@chromium.org

Review URL: https://codereview.appspot.com/14441075

Conflicts:
	src/common/version.h
	src/compiler/translator.vcxproj
	src/compiler/translator.vcxproj.filters
	src/compiler/translator/OutputHLSL.cpp
	src/libGLESv2/ProgramBinary.cpp
	src/libGLESv2/Shader.cpp
	src/libGLESv2/Shader.h

Change-Id: Iaf9f10b5de7b33c927ef032f3c4fe9d5095f64dd

src/compiler/translator/OutputHLSL.cpp

diff --git a/src/compiler/translator/OutputHLSL.cpp b/src/compiler/translator/OutputHLSL.cpp
index c410ba2..7009390 100644
--- a/src/compiler/translator/OutputHLSL.cpp
+++ b/src/compiler/translator/OutputHLSL.cpp
@@ -15,6 +15,7 @@
 #include "compiler/translator/UnfoldShortCircuit.h"
 #include "compiler/translator/HLSLLayoutEncoder.h"
 #include "compiler/translator/FlagStd140Structs.h"
+#include "compiler/translator/NodeSearch.h"
 
 #include <algorithm>
 #include <cfloat>
@@ -121,6 +122,7 @@
     mUsesAtan2_2 = false;
     mUsesAtan2_3 = false;
     mUsesAtan2_4 = false;
+    mUsesDiscardRewriting = false;
 
     mNumRenderTargets = resources.EXT_draw_buffers ? resources.MaxDrawBuffers : 1;
 
@@ -663,6 +665,11 @@
         out << *constructor;
     }
 
+    if (mUsesDiscardRewriting)
+    {
+        out << "#define ANGLE_USES_DISCARD_REWRITING" << "\n";
+    }
+
     if (mContext.shaderType == SH_FRAGMENT_SHADER)
     {
         TExtensionBehavior::const_iterator iter = mContext.extensionBehavior().find("GL_EXT_draw_buffers");
@@ -1883,15 +1890,31 @@
       case EOpMatrixTimesVector: outputTriplet(visit, "mul(transpose(", "), ", ")"); break;
       case EOpMatrixTimesMatrix: outputTriplet(visit, "transpose(mul(transpose(", "), transpose(", ")))"); break;
       case EOpLogicalOr:
-        out << "s" << mUnfoldShortCircuit->getNextTemporaryIndex();
-        return false;
+        if (node->getRight()->hasSideEffects())
+        {
+            out << "s" << mUnfoldShortCircuit->getNextTemporaryIndex();
+            return false;
+        }
+        else
+        {
+           outputTriplet(visit, "(", " || ", ")");
+           return true;
+        }
       case EOpLogicalXor:
         mUsesXor = true;
         outputTriplet(visit, "xor(", ", ", ")");
         break;
       case EOpLogicalAnd:
-        out << "s" << mUnfoldShortCircuit->getNextTemporaryIndex();
-        return false;
+        if (node->getRight()->hasSideEffects())
+        {
+            out << "s" << mUnfoldShortCircuit->getNextTemporaryIndex();
+            return false;
+        }
+        else
+        {
+           outputTriplet(visit, "(", " && ", ")");
+           return true;
+        }
       default: UNREACHABLE();
     }
 
@@ -2483,7 +2506,7 @@
     {
         mUnfoldShortCircuit->traverse(node->getCondition());
 
-        out << "if(";
+        out << "if (";
 
         node->getCondition()->traverse(this);
 
@@ -2492,9 +2515,14 @@
         outputLineDirective(node->getLine().first_line);
         out << "{\n";
 
+        bool discard = false;
+
         if (node->getTrueBlock())
         {
             traverseStatements(node->getTrueBlock());
+
+            // Detect true discard
+            discard = (discard || FindDiscard::search(node->getTrueBlock()));
         }
 
         outputLineDirective(node->getLine().first_line);
@@ -2512,6 +2540,15 @@
 
             outputLineDirective(node->getFalseBlock()->getLine().first_line);
             out << ";\n}\n";
+
+            // Detect false discard
+            discard = (discard || FindDiscard::search(node->getFalseBlock()));
+        }
+
+        // ANGLE issue 486: Detect problematic conditional discard
+        if (discard && FindSideEffectRewriting::search(node))
+        {
+            mUsesDiscardRewriting = true;
         }
     }
 
@@ -2609,7 +2646,9 @@
 
     switch (node->getFlowOp())
     {
-      case EOpKill:     outputTriplet(visit, "discard;\n", "", "");  break;
+      case EOpKill:
+        outputTriplet(visit, "discard;\n", "", "");
+        break;
       case EOpBreak:
         if (visit == PreVisit)
         {
@@ -2832,7 +2871,7 @@
 
                 if (!firstLoopFragment)
                 {
-                    out << "if(!Break";
+                    out << "if (!Break";
                     index->traverse(this);
                     out << ") {\n";
                 }