[llvm] r372490 - [InstSimplify][NFC] Reorganize simplifyUnsignedRangeCheck() to emphasize and/or symmetry

[Roman Lebedev via llvm-commits]

Author: lebedevri
Date: Sat Sep 21 15:27:28 2019
New Revision: 372490

URL: http://llvm.org/viewvc/llvm-project?rev=372490&view=rev
Log:
[InstSimplify][NFC] Reorganize simplifyUnsignedRangeCheck() to emphasize and/or symmetry

Only a single `X >= Y && Y == 0  -->  Y == 0` fold appears to be missing.

Modified:
    llvm/trunk/lib/Analysis/InstructionSimplify.cpp

Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=372490&r1=372489&r2=372490&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Sat Sep 21 15:27:28 2019
@@ -1443,25 +1443,28 @@ static Value *simplifyUnsignedRangeCheck
       isKnownNonZero(X, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT))
     return IsAnd ? UnsignedICmp : ZeroICmp;
 
+  // X >= Y && Y == 0  -->  Y == 0    FIXME
+  // X >= Y || Y == 0  -->  X >= Y
+  if (UnsignedPred == ICmpInst::ICMP_UGE && EqPred == ICmpInst::ICMP_EQ &&
+      !IsAnd)
+    return UnsignedICmp;
+
   // X > Y && Y == 0  -->  Y == 0  iff X != 0
   // X > Y || Y == 0  -->  X > Y   iff X != 0
   if (UnsignedPred == ICmpInst::ICMP_UGT && EqPred == ICmpInst::ICMP_EQ &&
       isKnownNonZero(X, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT))
     return IsAnd ? ZeroICmp : UnsignedICmp;
 
-  // X >= Y || Y != 0  -->  true
-  // X >= Y || Y == 0  -->  X >= Y
-  if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
-    if (EqPred == ICmpInst::ICMP_NE)
-      return getTrue(UnsignedICmp->getType());
-    return UnsignedICmp;
-  }
-
   // X < Y && Y == 0  -->  false
   if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
       IsAnd)
     return getFalse(UnsignedICmp->getType());
 
+  // X >= Y || Y != 0  -->  true
+  if (UnsignedPred == ICmpInst::ICMP_UGE && EqPred == ICmpInst::ICMP_NE &&
+      !IsAnd)
+    return getTrue(UnsignedICmp->getType());
+
   return nullptr;
 }