1 files changed, 11 insertions, 2 deletions
diff --git a/gnu/llvm/lib/Transforms/Utils/BypassSlowDivision.cpp b/gnu/llvm/lib/Transforms/Utils/BypassSlowDivision.cpp
index f711b192f60..e7828af648a 100644
--- a/gnu/llvm/lib/Transforms/Utils/BypassSlowDivision.cpp
+++ b/gnu/llvm/lib/Transforms/Utils/BypassSlowDivision.cpp
@@ -21,6 +21,7 @@
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Constants.h"
@@ -34,7 +35,6 @@
 #include "llvm/IR/Value.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/KnownBits.h"
-#include "llvm/Transforms/Utils/Local.h"
 #include <cassert>
 #include <cstdint>
 
@@ -173,7 +173,7 @@ Value *FastDivInsertionTask::getReplacement(DivCacheTy &Cache) {
   return isDivisionOp() ? Value.Quotient : Value.Remainder;
 }
 
-/// \brief Check if a value looks like a hash.
+/// Check if a value looks like a hash.
 ///
 /// The routine is expected to detect values computed using the most common hash
 /// algorithms. Typically, hash computations end with one of the following
@@ -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