Vulkan: Avoid using assign with BitSets

FastIntegerSet::clear() now calls reset() instead of assign(). std::vector::assign(...) invokes the copy-constructor. For better performance, especially with BitSet*, we can leverage the reset() method. This removes 1.2% CPU overhead from a Manhattan30 offscreen run Bug: angleproject:5689 Change-Id: Ib1a760587ffe18341b8ed892a732c506fc50c82b Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2723494 Commit-Queue: Mohan Maiya <m.maiya@samsung.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>

Vulkan: Avoid using assign with BitSets
c508e707 · Mohan Maiya · Commit Bot · 2b55f876 · c508e707
Commit c508e707 authored Feb 25, 2021 by Mohan Maiya Committed by Commit Bot Feb 27, 2021
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FastVector.h src/common/FastVector.h +9 -3

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--- a/src/common/FastVector.h
+++ b/src/common/FastVector.h
@@ -561,11 +561,17 @@ class FastIntegerSet final
        return (sizedKey < capacity()) && (mKeyData[index].test(offset));
    }

-    ANGLE_INLINE void clear() { mKeyData.assign(mKeyData.capacity(), KeyBitSet::Zero()); }
+    ANGLE_INLINE void clear()
+    {
+        for (KeyBitSet &it : mKeyData)
+        {
+            it.reset();
+        }
+    }

    ANGLE_INLINE bool empty() const
    {
-        for (KeyBitSet it : mKeyData)
+        for (const KeyBitSet &it : mKeyData)
        {
            if (it.any())
            {
@@ -578,7 +584,7 @@ class FastIntegerSet final
    ANGLE_INLINE size_t size() const
    {
        size_t valid_entries = 0;
-        for (KeyBitSet it : mKeyData)
+        for (const KeyBitSet &it : mKeyData)
        {
            valid_entries += it.count();
        }