Avoid overflowing a signed integer which triggers undefined behaviour.

Overflowing an unsigned integer is fine and behaves as you would expect.
Also fix a pasto, allowing SignExtend64 to take a 64-bit argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100517 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2010-04-06 03:12:43 +00:00
parent 3d32386992
commit adc6e06ff0

View File

@ -459,14 +459,14 @@ inline int64_t abs64(int64_t x) {
/// SignExtend32 - Sign extend B-bit number x to 32-bit int. /// SignExtend32 - Sign extend B-bit number x to 32-bit int.
/// Usage int32_t r = SignExtend32<5>(x); /// Usage int32_t r = SignExtend32<5>(x);
template <unsigned B> inline int32_t SignExtend32(int32_t x) { template <unsigned B> inline int32_t SignExtend32(uint32_t x) {
return (x << (32 - B)) >> (32 - B); return int32_t(x << (32 - B)) >> (32 - B);
} }
/// SignExtend64 - Sign extend B-bit number x to 64-bit int. /// SignExtend64 - Sign extend B-bit number x to 64-bit int.
/// Usage int64_t r = SignExtend64<5>(x); /// Usage int64_t r = SignExtend64<5>(x);
template <unsigned B> inline int64_t SignExtend64(int32_t x) { template <unsigned B> inline int64_t SignExtend64(uint64_t x) {
return (x << (64 - B)) >> (64 - B); return int64_t(x << (64 - B)) >> (64 - B);
} }
} // End llvm namespace } // End llvm namespace