[PATCH] D22442: Add assertions checking SignExtend{32, 64}'s bit width.

[Justin Lebar via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL275720: Add assertions checking SignExtend{32,64}'s bit width. (authored by jlebar).

Changed prior to commit:
  https://reviews.llvm.org/D22442?vs=64234&id=64259#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D22442

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

Index: llvm/trunk/include/llvm/Support/MathExtras.h
===================================================================
--- llvm/trunk/include/llvm/Support/MathExtras.h
+++ llvm/trunk/include/llvm/Support/MathExtras.h
@@ -672,27 +672,35 @@
   return alignTo(Value, Align) - Value;
 }
 
-/// SignExtend32 - Sign extend B-bit number x to 32-bit int.
-/// Usage int32_t r = SignExtend32<5>(x);
-template <unsigned B> inline int32_t SignExtend32(uint32_t x) {
-  return int32_t(x << (32 - B)) >> (32 - B);
+/// Sign-extend the number in the bottom B bits of X to a 32-bit integer.
+/// Requires 0 < B <= 32.
+template <unsigned B> inline int32_t SignExtend32(uint32_t X) {
+  static_assert(B > 0, "Bit width can't be 0.");
+  static_assert(B <= 32, "Bit width out of range.");
+  return int32_t(X << (32 - B)) >> (32 - B);
 }
 
-/// \brief Sign extend number in the bottom B bits of X to a 32-bit int.
-/// Requires 0 < B <= 32.
+/// Sign-extend the number in the bottom B bits of X to a 32-bit integer.
+/// Requires 0 < B < 32.
 inline int32_t SignExtend32(uint32_t X, unsigned B) {
+  assert(B > 0 && "Bit width can't be 0.");
+  assert(B <= 32 && "Bit width out of range.");
   return int32_t(X << (32 - B)) >> (32 - B);
 }
 
-/// SignExtend64 - Sign extend B-bit number x to 64-bit int.
-/// Usage int64_t r = SignExtend64<5>(x);
+/// Sign-extend the number in the bottom B bits of X to a 64-bit integer.
+/// Requires 0 < B < 64.
 template <unsigned B> inline int64_t SignExtend64(uint64_t x) {
+  static_assert(B > 0, "Bit width can't be 0.");
+  static_assert(B <= 64, "Bit width out of range.");
   return int64_t(x << (64 - B)) >> (64 - B);
 }
 
-/// \brief Sign extend number in the bottom B bits of X to a 64-bit int.
-/// Requires 0 < B <= 64.
+/// Sign-extend the number in the bottom B bits of X to a 64-bit integer.
+/// Requires 0 < B < 64.
 inline int64_t SignExtend64(uint64_t X, unsigned B) {
+  assert(B > 0 && "Bit width can't be 0.");
+  assert(B <= 64 && "Bit width out of range.");
   return int64_t(X << (64 - B)) >> (64 - B);
 }
 


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