llvm-project/llvm/test/Transforms/Inline/inline-cold-callee.ll
James Molloy 6df8f27c95 [InlineCost] Remove skew when calculating call costs
When calculating the cost of a call instruction we were applying a heuristic penalty as well as the cost of the instruction itself.

However, when calculating the benefit from inlining we weren't discounting the equivalent penalty for the call instruction that would be removed! This caused skew in the calculation and meant we wouldn't inline in the following, trivial case:

  int g() {
    h();
  }
  int f() {
    g();
  }

llvm-svn: 286814
2016-11-14 11:14:41 +00:00

55 lines
1.5 KiB
LLVM

; RUN: opt < %s -inline -inlinecold-threshold=0 -S | FileCheck %s
; This tests that a cold callee gets the (lower) inlinecold-threshold even without
; Cold hint and does not get inlined because the cost exceeds the inlinecold-threshold.
; A callee with identical body does gets inlined because cost fits within the
; inline-threshold
define i32 @callee1(i32 %x) !prof !21 {
%x1 = add i32 %x, 1
%x2 = add i32 %x1, 1
%x3 = add i32 %x2, 1
call void @extern()
ret i32 %x3
}
define i32 @callee2(i32 %x) !prof !22 {
; CHECK-LABEL: @callee2(
%x1 = add i32 %x, 1
%x2 = add i32 %x1, 1
%x3 = add i32 %x2, 1
call void @extern()
ret i32 %x3
}
define i32 @caller2(i32 %y1) !prof !22 {
; CHECK-LABEL: @caller2(
; CHECK: call i32 @callee2
; CHECK-NOT: call i32 @callee1
; CHECK: ret i32 %x3.i
%y2 = call i32 @callee2(i32 %y1)
%y3 = call i32 @callee1(i32 %y2)
ret i32 %y3
}
declare void @extern()
!llvm.module.flags = !{!1}
!21 = !{!"function_entry_count", i64 100}
!22 = !{!"function_entry_count", i64 1}
!1 = !{i32 1, !"ProfileSummary", !2}
!2 = !{!3, !4, !5, !6, !7, !8, !9, !10}
!3 = !{!"ProfileFormat", !"InstrProf"}
!4 = !{!"TotalCount", i64 10000}
!5 = !{!"MaxCount", i64 1000}
!6 = !{!"MaxInternalCount", i64 1}
!7 = !{!"MaxFunctionCount", i64 1000}
!8 = !{!"NumCounts", i64 3}
!9 = !{!"NumFunctions", i64 3}
!10 = !{!"DetailedSummary", !11}
!11 = !{!12, !13, !14}
!12 = !{i32 10000, i64 100, i32 1}
!13 = !{i32 999000, i64 100, i32 1}
!14 = !{i32 999999, i64 1, i32 2}