[llvm] aea6b9d - [Support] replace check with assert in known bits of mul calculation; NFC

[Sanjay Patel via llvm-commits]

Author: Sanjay Patel
Date: 2021-12-01T13:41:12-05:00
New Revision: aea6b9dceeb6b1f2a677e2e9010029f56f8282e7

URL: https://github.com/llvm/llvm-project/commit/aea6b9dceeb6b1f2a677e2e9010029f56f8282e7
DIFF: https://github.com/llvm/llvm-project/commit/aea6b9dceeb6b1f2a677e2e9010029f56f8282e7.diff

LOG: [Support] replace check with assert in known bits of mul calculation; NFC

Added: 
    

Modified: 
    llvm/lib/Support/KnownBits.cpp

Removed: 
    


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diff  --git a/llvm/lib/Support/KnownBits.cpp b/llvm/lib/Support/KnownBits.cpp
index 90483817c3029..554e3248524c6 100644
--- a/llvm/lib/Support/KnownBits.cpp
+++ b/llvm/lib/Support/KnownBits.cpp
@@ -421,11 +421,10 @@ KnownBits KnownBits::mul(const KnownBits &LHS, const KnownBits &RHS,
          "Self multiplication knownbits mismatch");
 
   // Compute a conservative estimate for high known-0 bits.
-  unsigned LeadZ =
-      std::max(LHS.countMinLeadingZeros() + RHS.countMinLeadingZeros(),
-               BitWidth) -
-      BitWidth;
-  LeadZ = std::min(LeadZ, BitWidth);
+  unsigned LHSLeadZ = LHS.countMinLeadingZeros();
+  unsigned RHSLeadZ = RHS.countMinLeadingZeros();
+  unsigned LeadZ = std::max(LHSLeadZ + RHSLeadZ, BitWidth) - BitWidth;
+  assert(LeadZ <= BitWidth && "More zeros than bits?");
 
   // The result of the bottom bits of an integer multiply can be
   // inferred by looking at the bottom bits of both operands and