[PATCH] D77403: [AssumeBundles] preserve knowledge in DCE

[Tyker via Phabricator via llvm-commits]

Tyker created this revision.
Tyker added a reviewer: jdoerfert.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D77403

Files:
  llvm/lib/Transforms/Scalar/DCE.cpp
  llvm/test/Transforms/DCE/basic-preservation.ll


Index: llvm/test/Transforms/DCE/basic-preservation.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/DCE/basic-preservation.ll
@@ -0,0 +1,11 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -dce -S --enable-knowledge-retention < %s | FileCheck %s
+
+define void @test(i32* %P) {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "dereferenceable"(i32* [[P:%.*]], i64 4), "nonnull"(i32* [[P]]) ]
+; CHECK-NEXT:    ret void
+;
+  %a = load i32, i32* %P
+  ret void
+}
Index: llvm/lib/Transforms/Scalar/DCE.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/DCE.cpp
+++ llvm/lib/Transforms/Scalar/DCE.cpp
@@ -25,6 +25,7 @@
 #include "llvm/Pass.h"
 #include "llvm/Support/DebugCounter.h"
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/AssumeBundleBuilder.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/Local.h"
 using namespace llvm;
@@ -127,6 +128,7 @@
       return false;
 
     salvageDebugInfo(*I);
+    salvageKnowledge(I);
 
     // Null out all of the instruction's operands to see if any operand becomes
     // dead as we go.


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