[PATCH] D151638: [TRE] icmp does not escape an alloca

[Joshua Cao via Phabricator via llvm-commits]

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Potentially fixes https://github.com/rust-lang/rust/issues/111603.
Marking tail calls helps MemCpyOptimizer and AliasAnalysis remove a
memcpy.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D151638

Files:
  llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
  llvm/test/Transforms/TailCallElim/basic.ll


Index: llvm/test/Transforms/TailCallElim/basic.ll
===================================================================
--- llvm/test/Transforms/TailCallElim/basic.ll
+++ llvm/test/Transforms/TailCallElim/basic.ll
@@ -245,7 +245,7 @@
 ; Test that using an alloca in a icmp does not escape it
 define void @test16() {
 ; CHECK-LABEL: @test16
-; CHECK-NOT: tail call void @noarg
+; CHECK: tail call void @noarg
 ; CHECK-NOT: tail call void @use
 entry:
   %alloca = alloca [100 x i32]
Index: llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -143,6 +143,7 @@
         }
         break;
       }
+      case Instruction::ICmp:
       case Instruction::Load: {
         // The result of a load is not alloca-derived (unless an alloca has
         // otherwise escaped, but this is a local analysis).


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