[RISCV] Avoid signed integer overflow UB in RISCVMatInt::generateInstSeq

Found by UBSan. llvm-svn: 366398
2019-07-18 04:02:58 +00:00 · 2019-07-18 04:02:58 +00:00 · 8aba95d64c
parent ad73a436dc
commit 8aba95d64c
1 changed files with 1 additions and 1 deletions
--- a/llvm/lib/Target/RISCV/Utils/RISCVMatInt.cpp
+++ b/llvm/lib/Target/RISCV/Utils/RISCVMatInt.cpp
@ -64,7 +64,7 @@ void generateInstSeq(int64_t Val, bool IsRV64, InstSeq &Res) {
  // performed when the recursion returns.

  int64_t Lo12 = SignExtend64<12>(Val);
-  int64_t Hi52 = (Val + 0x800) >> 12;
+  int64_t Hi52 = ((uint64_t)Val + 0x800ull) >> 12;
  int ShiftAmount = 12 + findFirstSet((uint64_t)Hi52);
  Hi52 = SignExtend64(Hi52 >> (ShiftAmount - 12), 64 - ShiftAmount);