diff options
Diffstat (limited to 'src/random.cpp')
| -rw-r--r-- | src/random.cpp | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/random.cpp b/src/random.cpp index b408b1e13e..5b8782d1ce 100644 --- a/src/random.cpp +++ b/src/random.cpp @@ -116,7 +116,10 @@ static uint64_t GetRdRand() noexcept // RdRand may very rarely fail. Invoke it up to 10 times in a loop to reduce this risk. #ifdef __i386__ uint8_t ok; - uint32_t r1, r2; + // Initialize to 0 to silence a compiler warning that r1 or r2 may be used + // uninitialized. Even if rdrand fails (!ok) it will set the output to 0, + // but there is no way that the compiler could know that. + uint32_t r1 = 0, r2 = 0; for (int i = 0; i < 10; ++i) { __asm__ volatile (".byte 0x0f, 0xc7, 0xf0; setc %1" : "=a"(r1), "=q"(ok) :: "cc"); // rdrand %eax if (ok) break; @@ -128,7 +131,7 @@ static uint64_t GetRdRand() noexcept return (((uint64_t)r2) << 32) | r1; #elif defined(__x86_64__) || defined(__amd64__) uint8_t ok; - uint64_t r1; + uint64_t r1 = 0; // See above why we initialize to 0. for (int i = 0; i < 10; ++i) { __asm__ volatile (".byte 0x48, 0x0f, 0xc7, 0xf0; setc %1" : "=a"(r1), "=q"(ok) :: "cc"); // rdrand %rax if (ok) break; |