Revert "[LSR] Avoid UB overflow when examining reuse opportunities"

This reverts commit r324943. Breaking bots, reverting for Gerolf. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@324958 91177308-0d34-0410-b5e6-96231b3b80d8
GiorgioNatili · Feb 12, 2018 · 0d1fcac · 0d1fcac
1 parent ddc563a
commit 0d1fcac
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diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3939,11 +3939,6 @@ void LSRInstance::GenerateCrossUseConstantOffsets() {
     if (Imms.size() == 1)
       continue;
 
-    // UB: Check for overflow
-    int64_t Res;
-    if (__builtin_saddll_overflow(Imms.begin()->first, std::prev(Imms.end())->first, &Res))
-      continue;
-
     DEBUG(dbgs() << "Generating cross-use offsets for " << *Reg << ':';
           for (const auto &Entry : Imms)
             dbgs() << ' ' << Entry.first;

diff --git a/test/CodeGen/X86/loop-strength-reduce-overflow-check.ll b/test/CodeGen/X86/loop-strength-reduce-overflow-check.ll