1 files changed, 23 insertions, 25 deletions
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index c46215067a6..668c572942f 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -162,13 +162,13 @@ static bool CanElideOverflowCheck(const ASTContext &Ctx, const BinOpInfo &Op) {
   // we can elide the overflow check.
   if (!Op.mayHaveIntegerOverflow())
     return true;
-
-  // If a unary op has a widened operand, the op cannot overflow.
-  if (const auto *UO = dyn_cast<UnaryOperator>(Op.E))
-    return IsWidenedIntegerOp(Ctx, UO->getSubExpr());
-
-  // We usually don't need overflow checks for binops with widened operands.
-  // Multiplication with promoted unsigned operands is a special case.
+
+  // If a unary op has a widened operand, the op cannot overflow.
+  if (const auto *UO = dyn_cast<UnaryOperator>(Op.E))
+    return !UO->canOverflow();
+
+  // We usually don't need overflow checks for binops with widened operands.
+  // Multiplication with promoted unsigned operands is a special case.
   const auto *BO = cast<BinaryOperator>(Op.E);
   auto OptionalLHSTy = getUnwidenedIntegerType(Ctx, BO->getLHS());
   if (!OptionalLHSTy)
@@ -1870,13 +1870,13 @@ llvm::Value *ScalarExprEmitter::EmitIncDecConsiderOverflowBehavior(
     return Builder.CreateAdd(InVal, Amount, Name);
   case LangOptions::SOB_Undefined:
     if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
-      return Builder.CreateNSWAdd(InVal, Amount, Name);
-    // Fall through.
-  case LangOptions::SOB_Trapping:
-    if (IsWidenedIntegerOp(CGF.getContext(), E->getSubExpr()))
-      return Builder.CreateNSWAdd(InVal, Amount, Name);
-    return EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec(E, InVal, IsInc));
-  }
+      return Builder.CreateNSWAdd(InVal, Amount, Name);
+    // Fall through.
+  case LangOptions::SOB_Trapping:
+    if (!E->canOverflow())
+      return Builder.CreateNSWAdd(InVal, Amount, Name);
+    return EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec(E, InVal, IsInc));
+  }
   llvm_unreachable("Unknown SignedOverflowBehaviorTy");
 }
 
@@ -1952,17 +1952,15 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
     value = Builder.getTrue();
 
   // Most common case by far: integer increment.
-  } else if (type->isIntegerType()) {
-    // Note that signed integer inc/dec with width less than int can't
-    // overflow because of promotion rules; we're just eliding a few steps here.
-    bool CanOverflow = value->getType()->getIntegerBitWidth() >=
-                       CGF.IntTy->getIntegerBitWidth();
-    if (CanOverflow && type->isSignedIntegerOrEnumerationType()) {
-      value = EmitIncDecConsiderOverflowBehavior(E, value, isInc);
-    } else if (CanOverflow && type->isUnsignedIntegerType() &&
-               CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) {
-      value =
-          EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec(E, value, isInc));
+  } else if (type->isIntegerType()) {
+    // Note that signed integer inc/dec with width less than int can't
+    // overflow because of promotion rules; we're just eliding a few steps here.
+    if (E->canOverflow() && type->isSignedIntegerOrEnumerationType()) {
+      value = EmitIncDecConsiderOverflowBehavior(E, value, isInc);
+    } else if (E->canOverflow() && type->isUnsignedIntegerType() &&
+               CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) {
+      value =
+          EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec(E, value, isInc));
     } else {
       llvm::Value *amt = llvm::ConstantInt::get(value->getType(), amount, true);
       value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec");