[llvm] r305607 - [ConstantRange] Implement getSignedMin/Max in a less complicated and faster way

[Craig Topper via llvm-commits]

Author: ctopper
Date: Fri Jun 16 18:26:23 2017
New Revision: 305607

URL: http://llvm.org/viewvc/llvm-project?rev=305607&view=rev
Log:
[ConstantRange] Implement getSignedMin/Max in a less complicated and faster way

Summary: As far as I can tell we should be able to implement these almost the same way we do unsigned, but using signed comparisons and checks for min signed value instead of min unsigned value.

Reviewers: pete, davide, sanjoy

Reviewed By: davide

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D33815

Modified:
    llvm/trunk/lib/IR/ConstantRange.cpp

Modified: llvm/trunk/lib/IR/ConstantRange.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/ConstantRange.cpp?rev=305607&r1=305606&r2=305607&view=diff
==============================================================================
--- llvm/trunk/lib/IR/ConstantRange.cpp (original)
+++ llvm/trunk/lib/IR/ConstantRange.cpp Fri Jun 16 18:26:23 2017
@@ -284,27 +284,14 @@ APInt ConstantRange::getUnsignedMin() co
 }
 
 APInt ConstantRange::getSignedMax() const {
-  if (!isWrappedSet()) {
-    APInt UpperMinusOne = getUpper() - 1;
-    if (getLower().sle(UpperMinusOne))
-      return UpperMinusOne;
-    return APInt::getSignedMaxValue(getBitWidth());
-  }
-  if (getLower().isNegative() == getUpper().isNegative())
+  if (isFullSet() || Lower.sgt(Upper))
     return APInt::getSignedMaxValue(getBitWidth());
   return getUpper() - 1;
 }
 
 APInt ConstantRange::getSignedMin() const {
-  if (!isWrappedSet()) {
-    if (getLower().sle(getUpper() - 1))
-      return getLower();
+  if (isFullSet() || (Lower.sgt(Upper) && !getUpper().isMinSignedValue()))
     return APInt::getSignedMinValue(getBitWidth());
-  }
-  if ((getUpper() - 1).slt(getLower())) {
-    if (!getUpper().isMinSignedValue())
-      return APInt::getSignedMinValue(getBitWidth());
-  }
   return getLower();
 }