commit d4b5054dc434e67bc59180ad199269d8485fedc3
author Corentin Wallez <cwallez@chromium.org> Mon Sep 28 12:19:26 2015 -0700
committer Corentin Wallez <cwallez@chromium.org> Wed Sep 30 20:49:42 2015 +0000
tree 0481c5ff740072542956f97312621272c47a51a8
parent 7b43c9b075495b519192e685df5e95d813315fff

compiler: Rewrite do-while loops as while loops

This works around a Mac driver shader compiler bug that makes many
do-while loops cause GPU-hangs when ran.

BUG=angleproject:891

Change-Id: I29828d6ea9e887ad0ed0c577f1deb41fb632a900
Reviewed-on: https://chromium-review.googlesource.com/302465
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>

src/compiler/translator/Compiler.cpp

diff --git a/src/compiler/translator/Compiler.cpp b/src/compiler/translator/Compiler.cpp
index 5994ede..9707250 100644
--- a/src/compiler/translator/Compiler.cpp
+++ b/src/compiler/translator/Compiler.cpp
@@ -16,6 +16,7 @@
 #include "compiler/translator/RegenerateStructNames.h"
 #include "compiler/translator/RemovePow.h"
 #include "compiler/translator/RenameFunction.h"
+#include "compiler/translator/RewriteDoWhile.h"
 #include "compiler/translator/ScalarizeVecAndMatConstructorArgs.h"
 #include "compiler/translator/UnfoldShortCircuitAST.h"
 #include "compiler/translator/ValidateLimitations.h"
@@ -143,7 +144,8 @@
       fragmentPrecisionHigh(false),
       clampingStrategy(SH_CLAMP_WITH_CLAMP_INTRINSIC),
       builtInFunctionEmulator(),
-      mSourcePath(NULL)
+      mSourcePath(NULL),
+      mTemporaryIndex(0)
 {
 }
 
@@ -320,6 +322,10 @@
         if (success && shaderType == GL_VERTEX_SHADER && (compileOptions & SH_INIT_GL_POSITION))
             initializeGLPosition(root);
 
+        // This pass might emit short circuits so keep it before the short circuit unfolding
+        if (success && (compileOptions & SH_REWRITE_DO_WHILE_LOOPS))
+            RewriteDoWhile(root, getTemporaryIndex());
+
         if (success && (compileOptions & SH_UNFOLD_SHORT_CIRCUIT))
         {
             UnfoldShortCircuitAST unfoldShortCircuit;
@@ -503,6 +509,7 @@
     nameMap.clear();
 
     mSourcePath = NULL;
+    mTemporaryIndex = 0;
 }
 
 bool TCompiler::initCallDag(TIntermNode *root)