[llvm] 417d695 - [InstSimplify] Reorder checks to be more efficient; NFC

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2020-03-20T22:05:38+01:00
New Revision: 417d69595f0c338bc7e3a8b2b990c3d5f8c04249

URL: https://github.com/llvm/llvm-project/commit/417d69595f0c338bc7e3a8b2b990c3d5f8c04249
DIFF: https://github.com/llvm/llvm-project/commit/417d69595f0c338bc7e3a8b2b990c3d5f8c04249.diff

LOG: [InstSimplify] Reorder checks to be more efficient; NFC

First check whether the RHS is a null pointer, and only then
perform a potentially expensive non-zero query.

Added: 
    

Modified: 
    llvm/lib/Analysis/InstructionSimplify.cpp

Removed: 
    


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diff  --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 1e4d7f711785..ba1f55048700 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -2340,10 +2340,9 @@ computePointerICmp(const DataLayout &DL, const TargetLibraryInfo *TLI,
   RHS = RHS->stripPointerCasts();
 
   // A non-null pointer is not equal to a null pointer.
-  if (llvm::isKnownNonZero(LHS, DL, 0, nullptr, nullptr, nullptr,
-                           IIQ.UseInstrInfo) &&
-      isa<ConstantPointerNull>(RHS) &&
-      (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
+  if (isa<ConstantPointerNull>(RHS) && ICmpInst::isEquality(Pred) &&
+      llvm::isKnownNonZero(LHS, DL, 0, nullptr, nullptr, nullptr,
+                           IIQ.UseInstrInfo))
     return ConstantInt::get(GetCompareTy(LHS),
                             !CmpInst::isTrueWhenEqual(Pred));