[PATCH] D149001: [InstSimplify] sdiv a (1 srem b) --> a

[Zhu Siyuan via Phabricator via llvm-commits]

floatshadow updated this revision to Diff 516129.
floatshadow edited the summary of this revision.
floatshadow added a comment.

clean diff following what junaire proposes

Depends on D149012 <https://reviews.llvm.org/D149012>


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D149001/new/

https://reviews.llvm.org/D149001

Files:
  llvm/lib/Analysis/InstructionSimplify.cpp


Index: llvm/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/lib/Analysis/InstructionSimplify.cpp
+++ llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1055,9 +1055,11 @@
   // If this is a boolean op (single-bit element type), we can't have
   // division-by-zero or remainder-by-zero, so assume the divisor is 1.
   // Similarly, if we're zero-extending a boolean divisor, then assume it's a 1.
+  // If this is an integer remainder (1 % Y), assume similarly the divisor is 1.
   Value *X;
   if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1) ||
-      (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
+      (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) ||
+      match(Op1, m_IRem(m_One(), m_Value())))
     return IsDiv ? Op0 : Constant::getNullValue(Ty);
 
   // If X * Y does not overflow, then:


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