[llvm-bugs] [Bug 43182] New: JumpThread/PRE of assumes with partially available conditions

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=43182

            Bug ID: 43182
           Summary: JumpThread/PRE of assumes with partially available
                    conditions
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
          Assignee: unassignedbugs at nondot.org
          Reporter: listmail at philipreames.com
                CC: llvm-bugs at lists.llvm.org

define void @test(i1 %cnd, i32* %p, i32 %v) {
  br i1 %cnd, label %taken, label %.merge_crit_edge

.merge_crit_edge:                                 ; preds = %0
  %load.pre = load i32, i32* %p, align 4
  br label %merge

taken:                                            ; preds = %0
  store i32 %v, i32* %p, align 4
  br label %merge

merge:                                            ; preds = %.merge_crit_edge,
%taken
  %load = phi i32 [ %load.pre, %.merge_crit_edge ], [ %v, %taken ]
  %c = icmp eq i32 %load, %v
  tail call void @llvm.assume(i1 %c)
  ret void
}

declare void @llvm.assume(i1)

The assume should be sunk into the .merge_crit_edge as the fact is trivially
known to be true along the taken path.

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