Metal: Early loop exit during attachments clear

src/common/bitset_utils_unittest.cpp

@@ -7,6 +7,8 @@
 //   Tests bitset helpers and custom classes.
 //
 
+#include <array>
+
 #include <gtest/gtest.h>
 
 #include "common/bitset_utils.h"
@@ -205,6 +207,28 @@ TYPED_TEST(BitSetIteratorTest, Iterator)
     EXPECT_EQ(originalValues.size(), readValues.size());
 }
 
+// Ensure lsb->msb iteration order.
+TYPED_TEST(BitSetIteratorTest, IterationOrder)
+{
+    TypeParam mStateBits                   = this->mStateBits;
+    const std::array<size_t, 8> writeOrder = {20, 25, 16, 31, 10, 14, 36, 19};
+    const std::array<size_t, 8> fetchOrder = {10, 14, 16, 19, 20, 25, 31, 36};
+
+    for (size_t value : writeOrder)
+    {
+        mStateBits.set(value);
+    }
+    EXPECT_EQ(writeOrder.size(), mStateBits.count());
+
+    size_t i = 0;
+    for (size_t bit : mStateBits)
+    {
+        EXPECT_EQ(fetchOrder[i], bit);
+        i++;
+    }
+    EXPECT_EQ(fetchOrder.size(), mStateBits.count());
+}
+
 // Test an empty iterator.
 TYPED_TEST(BitSetIteratorTest, EmptySet)
 {

src/libANGLE/renderer/metal/FrameBufferMtl.mm

@@ -1025,7 +1025,8 @@ angle::Result FramebufferMtl::clearWithDraw(const gl::Context *context,
     {
         if (drawbuffer >= mRenderPassDesc.numColorAttachments)
         {
-            continue;
+            // Iteration over drawbuffer indices always goes in ascending order
+            break;
         }
         RenderTargetMtl *renderTarget = mColorRenderTargets[drawbuffer];
         if (!renderTarget || !renderTarget->getTexture())