[llvm-bugs] [Bug 47493] New: Missed cases by Memory SSA DSE, works with legacy DSE

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=47493

            Bug ID: 47493
           Summary: Missed cases by Memory SSA DSE, works with legacy DSE
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
          Assignee: unassignedbugs at nondot.org
          Reporter: david.bolvansky at gmail.com
                CC: llvm-bugs at lists.llvm.org

define void @killed_by_load(i8* %a, i8* %b) {

bb0:
  store i8 undef, i8* %a
  br label %bb1
bb1:
  %tmp = load i8, i8* %b
  store i8 undef, i8* %a
  ret void
}


-basic-aa -dse -enable-dse-memoryssa=false

define void @killed_by_load(i8* %a, i8* %b) {
  store i8 undef, i8* %a, align 1
  br label %bb1

bb1: ; preds = %bb0
  store i8 undef, i8* %a, align 1
  ret void
}

-basic-aa -dse -enable-dse-memoryssa=true

define void @killed_by_load(i8* %a, i8* %b) {
  store i8 undef, i8* %a, align 1
  br label %bb1

bb1: ; preds = %bb0
  %tmp = load i8, i8* %b, align 1
  store i8 undef, i8* %a, align 1
  ret void
}

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20200911/80737077/attachment-0001.html>