[PATCH] D150142: [InstCombine] Add simplifications for div/rem with `i1` operands; PR62607

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


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Comment at: llvm/lib/Analysis/InstructionSimplify.cpp:1133-1137
   // X / 1 -> X
   // X % 1 -> 0
   // If the divisor can only be zero or one, we can't have division-by-zero
   // or remainder-by-zero, so assume the divisor is 1.
   //   e.g. 1, zext (i8 X), sdiv X (Y and 1)
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Move this comment to the if below now?


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Comment at: llvm/test/Transforms/InstCombine/div-i1.ll:16
+true:
+  %y_true = and i1 %y, 0
+  br label %done
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Is there a more robust way to test this that doesn't rely on worklist order bugs? Something like an assume to zero in an instsimplify test? Or does that also get simplified early?


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Comment at: llvm/test/Transforms/InstCombine/pr62607.ll:6
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
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Remove triple.


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Comment at: llvm/test/Transforms/InstCombine/pr62607.ll:86
+  br label %bb_6
+}
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Is this already a minimal reduction per llvm-reduce?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D150142/new/

https://reviews.llvm.org/D150142