Constant folding support for calls to umul.with.overflow(), basically identical to the smul.with.overflow() code.

llvm-svn: 128379

2 files changed, 18 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index cd8d52c1c46..c6aad0cd582 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -1048,11 +1048,12 @@ llvm::canConstantFoldCallTo(const Function *F) {
   case Intrinsic::ctpop:
   case Intrinsic::ctlz:
   case Intrinsic::cttz:
-  case Intrinsic::uadd_with_overflow:
-  case Intrinsic::usub_with_overflow:
   case Intrinsic::sadd_with_overflow:
+  case Intrinsic::uadd_with_overflow:
   case Intrinsic::ssub_with_overflow:
+  case Intrinsic::usub_with_overflow:
   case Intrinsic::smul_with_overflow:
+  case Intrinsic::umul_with_overflow:
   case Intrinsic::convert_from_fp16:
   case Intrinsic::convert_to_fp16:
   case Intrinsic::x86_sse_cvtss2si:
@@ -1362,7 +1363,8 @@ llvm::ConstantFoldCall(Function *F,
         case Intrinsic::uadd_with_overflow:
         case Intrinsic::ssub_with_overflow:
         case Intrinsic::usub_with_overflow:
-        case Intrinsic::smul_with_overflow: {
+        case Intrinsic::smul_with_overflow:
+        case Intrinsic::umul_with_overflow: {
           APInt Res;
           bool Overflow;
           switch (F->getIntrinsicID()) {
@@ -1382,6 +1384,9 @@ llvm::ConstantFoldCall(Function *F,
           case Intrinsic::smul_with_overflow:
             Res = Op1->getValue().smul_ov(Op2->getValue(), Overflow);
             break;
+          case Intrinsic::umul_with_overflow:
+            Res = Op1->getValue().umul_ov(Op2->getValue(), Overflow);
+            break;
           }
           Constant *Ops[] = {
             ConstantInt::get(F->getContext(), Res),
diff --git a/llvm/lib/Support/APInt.cpp b/llvm/lib/Support/APInt.cpp
index f4aae72ecaf..5789721c3a8 100644
--- a/llvm/lib/Support/APInt.cpp
+++ b/llvm/lib/Support/APInt.cpp
@@ -2078,6 +2078,16 @@ APInt APInt::smul_ov(const APInt &RHS, bool &Overflow) const {
   return Res;
 }
 
+APInt APInt::umul_ov(const APInt &RHS, bool &Overflow) const {
+  APInt Res = *this * RHS;
+
+  if (*this != 0 && RHS != 0)
+    Overflow = Res.udiv(RHS) != *this || Res.udiv(*this) != RHS;
+  else
+    Overflow = false;
+  return Res;
+}
+
 APInt APInt::sshl_ov(unsigned ShAmt, bool &Overflow) const {
   Overflow = ShAmt >= getBitWidth();
   if (Overflow)