<div dir="ltr"><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Sep 22, 2020 at 8:38 PM Roman Lebedev via llvm-commits <<a href="mailto:llvm-commits@lists.llvm.org">llvm-commits@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
Author: Roman Lebedev<br>
Date: 2020-09-22T21:37:29+03:00<br>
New Revision: b38d897e802664034c7e6e4654328256ed370a61<br>
<br>
URL: <a href="https://github.com/llvm/llvm-project/commit/b38d897e802664034c7e6e4654328256ed370a61" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/b38d897e802664034c7e6e4654328256ed370a61</a><br>
DIFF: <a href="https://github.com/llvm/llvm-project/commit/b38d897e802664034c7e6e4654328256ed370a61.diff" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/b38d897e802664034c7e6e4654328256ed370a61.diff</a><br>
<br>
LOG: [ConstantRange] binaryXor(): special-case binary complement case - the result is precise<br>
<br>
Use the fact that `~X` is equivalent to `-1 - X`, which gives us<br>
fully-precise answer, and we only need to special-handle the wrapped case.<br>
<br>
This fires ~16k times for vanilla llvm test-suite + RawSpeed.<br>
<br>
Added: <br>
<br>
<br>
Modified: <br>
    llvm/include/llvm/IR/ConstantRange.h<br>
    llvm/lib/IR/ConstantRange.cpp<br>
    llvm/unittests/IR/ConstantRangeTest.cpp<br>
<br>
Removed: <br>
<br>
<br>
<br>
################################################################################<br>
diff  --git a/llvm/include/llvm/IR/ConstantRange.h b/llvm/include/llvm/IR/ConstantRange.h<br>
index 318532b24e83..494a14a10cdb 100644<br>
--- a/llvm/include/llvm/IR/ConstantRange.h<br>
+++ b/llvm/include/llvm/IR/ConstantRange.h<br>
@@ -409,6 +409,11 @@ class LLVM_NODISCARD ConstantRange {<br>
   /// value in \p Other.<br>
   ConstantRange srem(const ConstantRange &Other) const;<br>
<br>
+  /// Return a new range representing the possible values resulting from<br>
+  /// a binary-xor of a value in this range by an all-one value,<br>
+  /// aka bitwise complement operation.<br>
+  ConstantRange binaryNot() const;<br>
+<br>
   /// Return a new range representing the possible values resulting<br>
   /// from a binary-and of a value in this range by a value in \p Other.<br>
   ConstantRange binaryAnd(const ConstantRange &Other) const;<br>
<br>
diff  --git a/llvm/lib/IR/ConstantRange.cpp b/llvm/lib/IR/ConstantRange.cpp<br>
index 396c39b5b3a8..7b8dd66b993c 100644<br>
--- a/llvm/lib/IR/ConstantRange.cpp<br>
+++ b/llvm/lib/IR/ConstantRange.cpp<br>
@@ -1240,6 +1240,16 @@ ConstantRange ConstantRange::srem(const ConstantRange &RHS) const {<br>
   return ConstantRange(std::move(Lower), std::move(Upper));<br>
 }<br>
<br>
+ConstantRange ConstantRange::binaryNot() const {<br>
+  if (isEmptySet())<br>
+    return getEmpty();<br>
+<br>
+  if (isWrappedSet())<br>
+    return getFull();<br></blockquote><div><br></div><div>Probably don't need those checks, as you're forwarding to the sub() implementation anyway?</div><div><br></div><div>Nikita<br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
+<br>
+  return ConstantRange(APInt::getAllOnesValue(getBitWidth())).sub(*this);<br>
+}<br>
+<br>
 ConstantRange<br>
 ConstantRange::binaryAnd(const ConstantRange &Other) const {<br>
   if (isEmptySet() || Other.isEmptySet())<br>
@@ -1278,6 +1288,12 @@ ConstantRange ConstantRange::binaryXor(const ConstantRange &Other) const {<br>
   if (isSingleElement() && Other.isSingleElement())<br>
     return {*getSingleElement() ^ *Other.getSingleElement()};<br>
<br>
+  // Special-case binary complement, since we can give a precise answer.<br>
+  if (Other.isSingleElement() && Other.getSingleElement()->isAllOnesValue())<br>
+    return binaryNot();<br>
+  if (isSingleElement() && getSingleElement()->isAllOnesValue())<br>
+    return Other.binaryNot();<br>
+<br>
   // TODO: replace this with something less conservative<br>
   return getFull();<br>
 }<br>
<br>
diff  --git a/llvm/unittests/IR/ConstantRangeTest.cpp b/llvm/unittests/IR/ConstantRangeTest.cpp<br>
index 8bcc6efdc265..474a94af3932 100644<br>
--- a/llvm/unittests/IR/ConstantRangeTest.cpp<br>
+++ b/llvm/unittests/IR/ConstantRangeTest.cpp<br>
@@ -2349,4 +2349,22 @@ TEST_F(ConstantRangeTest, binaryXor) {<br>
   EXPECT_TRUE(R0_99.binaryXor(R16_35).isFullSet());<br>
 }<br>
<br>
+TEST_F(ConstantRangeTest, binaryNot) {<br>
+  TestUnsignedUnaryOpExhaustive(<br>
+      [](const ConstantRange &CR) { return CR.binaryNot(); },<br>
+      [](const APInt &N) { return ~N; });<br>
+  TestUnsignedUnaryOpExhaustive(<br>
+      [](const ConstantRange &CR) {<br>
+        return CR.binaryXor(<br>
+            ConstantRange(APInt::getAllOnesValue(CR.getBitWidth())));<br>
+      },<br>
+      [](const APInt &N) { return ~N; });<br>
+  TestUnsignedUnaryOpExhaustive(<br>
+      [](const ConstantRange &CR) {<br>
+        return ConstantRange(APInt::getAllOnesValue(CR.getBitWidth()))<br>
+            .binaryXor(CR);<br>
+      },<br>
+      [](const APInt &N) { return ~N; });<br>
+}<br>
+<br>
 }  // anonymous namespace<br>
<br>
<br>
<br>
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</blockquote></div></div>