llvm/test/Transforms/MergeFunc/merge-functions-select-weights.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -S -passes=mergefunc < %s | FileCheck %s
;

; Verify that MergeFunctions correctly combines select-instruction
; branch_weights when merging two structurally identical functions.
; Since FunctionComparator only considers functions equal when their
; control-flow graphs and instruction order match exactly, MergeFunctions
; can safely walk both functions in parallel and merge any instruction-level
; metadata it encounters.
;
; The functions sel_a and sel_b differ only in their entry counts and
; select branch_weights. When merged, the pass first converts each
; function's relative branch weights into absolute execution counts using
; its entry count, and then adds the counts together to produce the
; final merged weights.
;
; sel_a: entry 50,  weights 10:90  -> true=5,   false=45
; sel_b: entry 150, weights 30:70  -> true=45,  false=105
; Merged:                         true=5+45=50,  false=45+105=150

define internal i32 @sel_a(i32 %x) !prof !1 {
; CHECK-LABEL: define internal i32 @sel_a(
; CHECK-SAME: i32 [[X:%.*]]) !prof [[PROF0:![0-9]+]] {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[X]], 0
; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], i32 1, i32 0, !prof [[PROF1:![0-9]+]]
; CHECK-NEXT:    ret i32 [[SEL]]
;
entry:
  %cmp = icmp slt i32 %x, 0
  %sel = select i1 %cmp, i32 1, i32 0, !prof !2
  ret i32 %sel
}

define internal i32 @sel_b(i32 %x) !prof !3 {
entry:
  %cmp = icmp slt i32 %x, 0
  %sel = select i1 %cmp, i32 1, i32 0, !prof !4
  ret i32 %sel
}

!1 = !{!"function_entry_count", i64 50}
!2 = !{!"branch_weights", i32 10, i32 90}
!3 = !{!"function_entry_count", i64 150}
!4 = !{!"branch_weights", i32 30, i32 70}
;.
; CHECK: [[PROF0]] = !{!"function_entry_count", i64 200}
; CHECK: [[PROF1]] = !{!"branch_weights", i32 50, i32 150}
;.