vendor/llvm/llvm-release_70-r340910

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/Transforms/Utils/BypassSlowDivision.cpp b/lib/Transforms/Utils/BypassSlowDivision.cpp
index 05512a6dff3e5..e7828af648a91 100644
--- a/lib/Transforms/Utils/BypassSlowDivision.cpp
+++ b/lib/Transforms/Utils/BypassSlowDivision.cpp
@@ -388,6 +388,15 @@ Optional<QuotRemPair> FastDivInsertionTask::insertFastDivAndRem() {
     return None;
   }
 
+  // After Constant Hoisting pass, long constants may be represented as
+  // bitcast instructions. As a result, some constants may look like an
+  // instruction at first, and an additional check is necessary to find out if
+  // an operand is actually a constant.
+  if (auto *BCI = dyn_cast<BitCastInst>(Divisor))
+    if (BCI->getParent() == SlowDivOrRem->getParent() &&
+        isa<ConstantInt>(BCI->getOperand(0)))
+      return None;
+
   if (DividendShort && !isSignedOp()) {
     // If the division is unsigned and Dividend is known to be short, then
     // either