[PATCH] D77413: Support: Add specializations for reverseBits to use builtin

Matt Arsenault via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Fri Apr 3 09:41:01 PDT 2020


arsenm created this revision.
arsenm added reviewers: bkramer, aaron.ballman, Bigcheese, spatel.
Herald added subscribers: dexonsmith, wdng.

https://reviews.llvm.org/D77413

Files:
  llvm/include/llvm/Support/MathExtras.h


Index: llvm/include/llvm/Support/MathExtras.h
===================================================================
--- llvm/include/llvm/Support/MathExtras.h
+++ llvm/include/llvm/Support/MathExtras.h
@@ -313,6 +313,34 @@
   return Val;
 }
 
+#if __has_builtin(__builtin_bitreverse8)
+template<>
+inline uint8_t reverseBits<uint8_t>(uint8_t Val) {
+  return __builtin_bitreverse8(Val);
+}
+#endif
+
+#if __has_builtin(__builtin_bitreverse16)
+template<>
+inline uint16_t reverseBits<uint16_t>(uint16_t Val) {
+  return __builtin_bitreverse16(Val);
+}
+#endif
+
+#if __has_builtin(__builtin_bitreverse32)
+template<>
+inline uint32_t reverseBits<uint32_t>(uint32_t Val) {
+  return __builtin_bitreverse32(Val);
+}
+#endif
+
+#if __has_builtin(__builtin_bitreverse64)
+template<>
+inline uint64_t reverseBits<uint64_t>(uint64_t Val) {
+  return __builtin_bitreverse64(Val);
+}
+#endif
+
 // NOTE: The following support functions use the _32/_64 extensions instead of
 // type overloading so that signed and unsigned integers can be used without
 // ambiguity.


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