[PATCH] D60574: [ConstantRange] Add unsignedMulMayOverflow()

[Nikita Popov via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL358228: [ConstantRange] Add unsignedMulMayOverflow() (authored by nikic, committed by ).

Changed prior to commit:
  https://reviews.llvm.org/D60574?vs=194730&id=194756#toc

Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D60574/new/

https://reviews.llvm.org/D60574

Files:
  llvm/trunk/include/llvm/IR/ConstantRange.h
  llvm/trunk/lib/IR/ConstantRange.cpp
  llvm/trunk/unittests/IR/ConstantRangeTest.cpp


Index: llvm/trunk/include/llvm/IR/ConstantRange.h
===================================================================
--- llvm/trunk/include/llvm/IR/ConstantRange.h
+++ llvm/trunk/include/llvm/IR/ConstantRange.h
@@ -399,6 +399,9 @@
   /// Return whether signed sub of the two ranges always/never overflows.
   OverflowResult signedSubMayOverflow(const ConstantRange &Other) const;
 
+  /// Return whether unsigned mul of the two ranges always/never overflows.
+  OverflowResult unsignedMulMayOverflow(const ConstantRange &Other) const;
+
   /// Print out the bounds to a stream.
   void print(raw_ostream &OS) const;
 
Index: llvm/trunk/lib/IR/ConstantRange.cpp
===================================================================
--- llvm/trunk/lib/IR/ConstantRange.cpp
+++ llvm/trunk/lib/IR/ConstantRange.cpp
@@ -1252,6 +1252,26 @@
   return OverflowResult::NeverOverflows;
 }
 
+ConstantRange::OverflowResult ConstantRange::unsignedMulMayOverflow(
+    const ConstantRange &Other) const {
+  if (isEmptySet() || Other.isEmptySet())
+    return OverflowResult::MayOverflow;
+
+  APInt Min = getUnsignedMin(), Max = getUnsignedMax();
+  APInt OtherMin = Other.getUnsignedMin(), OtherMax = Other.getUnsignedMax();
+  bool Overflow;
+
+  (void) Min.umul_ov(OtherMin, Overflow);
+  if (Overflow)
+    return OverflowResult::AlwaysOverflows;
+
+  (void) Max.umul_ov(OtherMax, Overflow);
+  if (Overflow)
+    return OverflowResult::MayOverflow;
+
+  return OverflowResult::NeverOverflows;
+}
+
 void ConstantRange::print(raw_ostream &OS) const {
   if (isFullSet())
     OS << "full-set";
Index: llvm/trunk/unittests/IR/ConstantRangeTest.cpp
===================================================================
--- llvm/trunk/unittests/IR/ConstantRangeTest.cpp
+++ llvm/trunk/unittests/IR/ConstantRangeTest.cpp
@@ -1578,6 +1578,18 @@
       });
 }
 
+TEST_F(ConstantRangeTest, UnsignedMulOverflowExhaustive) {
+  TestOverflowExhaustive(
+      [](const APInt &N1, const APInt &N2) {
+        bool Overflow;
+        (void) N1.umul_ov(N2, Overflow);
+        return Overflow;
+      },
+      [](const ConstantRange &CR1, const ConstantRange &CR2) {
+        return CR1.unsignedMulMayOverflow(CR2);
+      });
+}
+
 TEST_F(ConstantRangeTest, SignedAddOverflowExhaustive) {
   TestOverflowExhaustive(
       [](const APInt &N1, const APInt &N2) {


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