[PATCH] D117300: [opt] Do not replace MD refs to destroyed constants with undef

[Stephen Tozer via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGea17d29a6c83: [llvm] Do not replace dead constant references in metadata with undef (authored by StephenTozer).

Changed prior to commit:
  https://reviews.llvm.org/D117300?vs=399942&id=402571#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D117300/new/

https://reviews.llvm.org/D117300

Files:
  llvm/lib/IR/Constants.cpp
  llvm/test/LTO/Resolution/X86/Inputs/no-undef-type-md.ll
  llvm/test/LTO/Resolution/X86/no-undef-type-md.ll


Index: llvm/test/LTO/Resolution/X86/no-undef-type-md.ll
===================================================================
--- /dev/null
+++ llvm/test/LTO/Resolution/X86/no-undef-type-md.ll
@@ -0,0 +1,37 @@
+; RUN: opt <%s -o %t0.o -thinlto-bc -thinlto-split-lto-unit
+; RUN: llvm-as -o %t1.o %S/Inputs/no-undef-type-md.ll
+; RUN: llvm-lto2 run -o a.out \
+; RUN: %t0.o \
+; RUN: -r=%t0.o,a, \
+; RUN: -r=%t0.o,b,pl \
+; RUN: %t1.o \
+; RUN: -r=%t1.o,a,pl \
+; RUN: | FileCheck --allow-empty --check-prefix=ERROR %s
+; RUN llvm-nm a.out.0 a.out.1 -S | FileCheck %s
+
+; ERROR-NOT: expected a Function or null
+; ERROR-NOT: i32 (%0*, i32*)* undef
+
+; CHECK: a.out.0:
+; CHECK: a.out.1:
+
+; ModuleID = 'test.cpp.o'
+source_filename = "test.cpp"
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @a() {
+entry:
+  ret i32 0
+}
+
+define i32 @b() {
+entry:
+  ret i32 0
+}
+
+!llvm.module.flags = !{!39}
+
+!39 = !{i32 5, !"CG Profile", !40}
+!40 = !{!41}
+!41 = !{i32 ()* @b, i32 ()* @a, i64 2594092}
Index: llvm/test/LTO/Resolution/X86/Inputs/no-undef-type-md.ll
===================================================================
--- /dev/null
+++ llvm/test/LTO/Resolution/X86/Inputs/no-undef-type-md.ll
@@ -0,0 +1,13 @@
+; ModuleID = 'test.cpp.o'
+source_filename = "test.cpp"
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @a()
+
+!llvm.module.flags = !{!9, !39}
+
+!9 = !{i32 1, !"EnableSplitLTOUnit", i32 1}
+!39 = !{i32 5, !"CG Profile", !40}
+!40 = !{!41}
+!41 = distinct !{null, i32 ()* bitcast (void ()* @a to i32 ()*), i64 2594092}
Index: llvm/lib/IR/Constants.cpp
===================================================================
--- llvm/lib/IR/Constants.cpp
+++ llvm/lib/IR/Constants.cpp
@@ -739,15 +739,8 @@
       ++I;
   }
 
-  if (RemoveDeadUsers) {
-    // If C is only used by metadata, it should not be preserved but should
-    // have its uses replaced.
-    if (C->isUsedByMetadata()) {
-      const_cast<Constant *>(C)->replaceAllUsesWith(
-          UndefValue::get(C->getType()));
-    }
+  if (RemoveDeadUsers)
     const_cast<Constant *>(C)->destroyConstant();
-  }
 
   return true;
 }


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